تلسکوپ فضایی جیمز وب

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تلسکوپ فضایی جیمز وب
JWST spacecraft model 2.png
معماری تلسکوپ فضایی جیمز وب با اجزای کامل آن
فهرست نام‌هاتلسکوپ فضایی نسل بعدی (۱۹۹۶–۲۰۰۲)
گونه مأموریترصدخانه فضایی
اپراتورSTScI (ناسا)[۱]
شناسهٔ کوسپار2021-130A
شماره ستکات50463[۲]
وبگاه
مدت مأموریت
  • ۱۰ سال (برنامه‌ریزی‌شده)
  • ۷ ماه، ۱۸ روز (سپری‌شده)
ویژگی‌های فضاپیما
سازنده
جرم پرتاب۶٬۱۶۱٫۴ کیلوگرم (۱۳٬۵۸۴ پوند)[۳]
ابعاد۲۰٫۱۹۷ در ۱۴٫۱۶۲ متر (۶۶٫۲۶ در ۴۶٫۴۶ فوت)
توان۲ وات
آغاز مأموریت
تاریخ راه‌اندازی۲۵ دسامبر ۲۰۲۱ (۲۰۲۱-12-۲۵)، ۱۲:۲۰ جهانی
موشکآریان ۵ (پرواز وی‌ای۲۵۶ آریان)
سایت پرتابپایگاه فضایی گویان، ELA-3
پیمان‌کارآریان‌اسپیس
مشخصات مداری
سامانه مرجعنقاط لاگرانژی
رژیم مأموریتمدار هاله
حضیض apsis۲۵۰٬۰۰۰ کیلومتر (۱۶۰٬۰۰۰ مایل)[۴][۵]
اوج apsis۸۳۲٬۰۰۰ کیلومتر (۵۱۷٬۰۰۰ مایل)
انحراف مداری۴٫۰۵۶۰[۲]
تناوب۶ ماه
تلسکوپ اصلی
گونهKorsch telescope
قطر۶٫۵ متر (۲۱ فوت)
فاصله کانونی۱۳۱٫۴ متر (۴۳۱ فوت)
Collecting area۲۵٫۴ متر مربع (۲۷۳ فوت مربع)[۶]
طول موج۰٫۶–۲۸٫۳ μm (نارنجی تا نیمه فروسرخ)
فرستنده
باند
پهنای باند
  • S-band up: 16 kbit/s
  • S-band down: 40 kbit/s
  • Ka-band down: up to 28 Mbit/s
JWST Launch Logo.png
نشان‌واره مأموریت تلسکوپ فضایی جیمز وب
نخستین تصویر زمینه ژرف جیمز وب از خوشه کهکشانی اس‌ام‌ای‌سی‌اس ۰۷۲۳

تلسکوپ فضایی جیمز وب (James Webb Space Telescope به اختصار JWST) یک تلسکوپ فضایی است که عمدتاً برای مطالعه اخترشناسی فروسرخ طراحی شده‌است. قدرتمندترین تلسکوپی که تا به حال به فضا پرتاب شده‌است، وضوح و حساسیت فروسرخ بسیار بهبودیافته، به آن اجازه می‌دهد تا اجرامی که برای تلسکوپ فضایی هابل بسیار قدیمی، دور و کم نور هستند، را مشاهده کند. انتظار می‌رود که این امر طیف وسیعی از تحقیقات را در زمینه‌های اخترشناسی و کیهان‌شناسی، مانند مشاهدات اولین ستاره‌ها و تشکیل اولین کهکشان‌ها، و توصیف دقیق اتمسفر سیارات فراخورشیدی بالقوه قابل سکونت را ممکن کند. تلسکوپ فضایی جیمز وب در دسامبر ۲۰۲۱ بر روی یک موشک آریان ۵ از کورو (کمون)، گویان فرانسه پرتاب شد و از مه ۲۰۲۲ در حال آزمایش و تراز کردن است. پس از عملیاتی شدن، انتظار می‌رود تا پایان ژوئن ۲۰۲۲، تلسکوپ فضایی جیمز وب به‌عنوان مأموریت شاخص ناسا در اخترفیزیک جانشین هابل شود.

ادارهٔ ملی هوانوردی و فضایی ایالات متحده (ناسا) توسعهٔ تلسکوپ فضایی جیمز وب را با همکاری آژانس فضایی اروپا (ESA) و آژانس فضایی کانادا (CSA) رهبری کرد. مرکز پرواز فضایی گودارد ناسا (GSFC) در مریلند توسعهٔ تلسکوپ را مدیریت کرد، مؤسسه علمی تلسکوپ فضایی در بالتیمور تلسکوپ فضایی جیمز وب را اداره می‌کند و پیمانکار اصلی نورتروپ گرومن بود. این تلسکوپ به افتخار جیمز ئی. وب، که از سال ۱۹۶۱ تا ۱۹۶۸ مدیر ناسا در طول برنامه‌های مرکوری، پروژه جمینای و آپولو بود، نامگذاری شده‌است.

آینهٔ اولیهٔ تلسکوپ فضایی جیمز وب از ۱۸ بخش آینهٔ شش‌ضلعی ساخته شده از بریلیم با روکش طلا تشکیل شده‌است که در مجموع آینه‌ای به قطر ۶٫۵ متر (۲۱ فوت) در مقایسه با ۲٫۴ متر (۷٫۹ فوت) هابل ایجاد می‌کند. این به تلسکوپ وب مساحت جمع‌آوری نور در حدود ۲۵ متر مربع، تقریباً ۶ برابر هابل، می‌دهد. برخلاف هابل که در طیف‌های فرابنفش، مرئی و فروسرخ نزدیک (۰٫۱–۱٫۷ میکرومتر) مشاهده می‌کند، JWST در محدودهٔ فرکانس پایین‌تر، از نور مرئی با طول موج بلند (قرمز) تا فروسرخ میانی (۰٫۶–۲۸٫۳ میکرومتر) رصد می‌کند). تلسکوپ باید بسیار سرد، زیر ۵۰ کلوین (۲۲۳- درجه سانتی‌گراد؛ ۳۷۰ درجه فارنهایت) نگه داشته شود تا سیگنال‌های ضعیفی را در فروسرخ بدون تداخل سایر منابع گرما مشاهده کند. این در یک مدار خورشیدی نزدیک نقطه لاگرانژ L2 خورشید-زمین، در حدود ۱٫۵ میلیون کیلومتری (۹۳۰۰۰۰ مایل) (حدود چهار برابر دورتر از مدار ماه) از زمین مستقر شده‌است، جایی که آفتابگیر پنج لایهٔ بادبادکی‌شکل آن از گرم شدن خورشید، زمین و ماه محافظت می‌کند. چندین هزار دانشمند، مهندس و تکنسین از ۱۵ کشور در ساخت و آزمایش تلسکوپ فضایی جیمز وب مشارکت داشته‌اند. در مجموع ۲۵۸ شرکت، سازمان دولتی و مؤسسهٔ دانشگاهی در این پروژه سهیم بوده‌اند. تلسکوپ فضایی جیمز وب چهار هدف کلیدی دارد: جستجوی نور از اولین ستاره‌ها و کهکشان‌هایی که پس از مه‌بانگ در جهان شکل گرفتند، مطالعهٔ شکل‌گیری و تکامل کهکشان‌ها، درک تشکیل ستاره و سیاره‌ها و مطالعهٔ سیستم‌های سیاره‌ای و منشأ حیات.

ویژگی‌ها[ویرایش]

تلسکوپ وزنی برابر با نصف وزن هابل دارد اما مساحت آینه اصلی آن بیش از ۶ برابر آینه هابل است.[۷] جیمز وب برای اخترشناسی مادون‌قرمز طراحی شده اما همچنین می‌تواند پرتوهای نارنجی و قرمز را نیز رصد کند.

تلسکوپ‌های زمینی باید از میان اتمسفر رصد کنند که بسیاری از امواج، غیرقابل مشاهده می‌شوند. حتی در جاهایی که اتمسفر شفاف است بسیاری از ترکیبات شیمیایی مانند آب، دی‌اکسید کربن و متان که در جو زمین وجود دارند کار تجزیه و تحلیل را بسیار سخت می‌کنند. تلسکوپ‌های فضایی موجود مانند هابل نمی‌توانند این دسته از امواج را مطالعه کنند، زیرا آینه‌ها به اندازهٔ کافی خنک نیستند (آینهٔ هابل در حدود ۱۵ درجهٔ سانتی‌گراد نگهداری می‌شود).

تلسکوپ در نزدیکی زمین و خورشید -در نقطه L2 لاگرانژی- حدود ۱٬۵۰۰٬۰۰۰ کیلومتری مدار زمین عمل می‌کند. برای مقایسه هابل در ۵۵۰ کیلومتری و ماه تقریباً در ۴۰۰هزار کیلومتری سطح زمین چرخش می‌کنند. این فاصله می‌تواند تعمیرات یا ارتقاء سخت‌افزار تلسکوپ را پس از راه‌اندازی، عملاً غیرممکن کند. اشیاء در این فاصله می‌توانند هماهنگ با زمین دور خورشید بچرخند که اجازه می‌دهد تلسکوپ در یک فاصله تقریباً ثابت از زمین باقی بماند و برای محافظت از گرما و نورِ خورشید و زمین از یک سپر خورشیدی استفاده کند. این باعث می‌شود که دمای فضاپیمای زیر ۲۲۰- درجهٔ سانتی‌گراد نگه داشته شود که برای رصد امواج مادون‌قرمز مورد نیاز است. پیمانکار اصلی این پروژه، شرکت نورثروپ گرومن است.

سپر خورشیدی[ویرایش]

برای رصد در طیف مادون‌قرمز، تلسکوپ باید بسیار سرد (زیر ۲۲۰- درجه سانتی‌گراد) نگه داشته شود در غیر این صورت تابش مادون‌قرمز اجزای تلسکوپ را در هم خواهد شکست؛ بنابراین، از یک سپر نوری بزرگ برای جلوگیری از نور و حرارتِ خورشید، زمین و ماه استفاده می‌شود و موقعیت آن در نزدیکی نقطه لاگرانژی خورشید تمام این سه جسم (خورشید، زمین و ماه) را در یک طرف فضاپیما نگه خواهد داشت.

سپر خورشیدی دارای پنج لایه است که از یک لایهٔ نازک از جنس پلی‌آمید ساخته شده‌است، به‌همراه اندودِ آلومینیم در یک طرف و سیلیکون در طرف دیگر سپر. اِشکال تصادفی ساختار این لایه‌های ظریف در طی آزمایش، یک عامل تأخیر در اجرای پروژه بود.

اپتیک[ویرایش]

آینهٔ اصلی در مرکز پرواز فضایی گودارد که در مِه ۲۰۱۶ مونتاژ شده‌است.

عنصر تلسکوپ نوری جیمز وب یک بازتابنده از جنس بریلیم با ابعاد ۶٫۵ متری با مساحت کل ۲۵ متر مربع است. این ابعاد برای تجهیزات پرتابی موجود بسیار بزرگ است، بنابراین آینه از ۱۸ قسمت شش ضلعی تشکیل شده‌است که پس از پرتاب تلسکوپ راه‌اندازی می‌شوند.

ابزار علمی[ویرایش]

ماژول یکپارچهٔ تجهیزات علمی (ISIM) چارچوبی است که توان الکتریکی، محاسبات منابع، قابلیت خنک‌سازی و همچنین پایداری ساختاری تلسکوپ وِب را فراهم می‌کند. مهندسان به این قسمت، قلب تلسکوپ می‌گویند.[۸] این قسمت با ترکیب گرافیتی-اپوکسی به زیر ساختار تلسکوپ جیمز وب متصل است. ISIM دارای چهار ابزار علمی و یک دوربین راهنما است.

  • دوربین رصد مادون‌قرمز نزدیک (NIRCam) یک تصویربردار بسیار دقیق و پیشرفته است که توسط دانشگاه آریزونا طراحی شده و روی ماژول ISIM نصب می‌شود. وظیفهٔ این بخش، تصویربرداری از نورهای طیف ۰٫۶ تا ۵ میکرومتر است همچنین به‌عنوان حسگر هماهنگ‌کننده عمل می‌کند تا بتواند هر ۱۸ آینه را به‌گونه‌ای تنظیم کند که بتوانند به‌عنوان آینه‌ای واحد عمل کنند. همکار دانشگاه آریزونا در ساخت NIRCam شرکت لاکهید مارتین است.
  • طیف‌سنج مادون‌قرمز نزدیک (NIRSpec) یک طیف‌سنج چند جرمی است که توسط آژانس فضایی اروپا طراحی شده‌است که می‌تواند به‌طور هم‌زمان طیف مادون‌قرمز را با رزولوشن پایین، متوسط و بالا اندازه‌گیری کند. طراحی NIRSpec سه حالت مشاهده را فراهم می‌کند: یک حالت با وضوح کم با استفاده از یک منشور، یک حالت با وضوح متوسط و حالت دیگری با وضوح بالا.
مدل NIRSpec
  • ادوات طیف‌سنج مادون‌قرمز میانه یا MIRI محدودهٔ طول موج مادون‌قرمز میانه را از ۵ تا ۲۷ میکرومتر اندازه‌گیری خواهد کرد. این قسمت شامل هر دو دوربین متوسط مادون‌قرمز و یک طیف‌سنج تصویربرداری است. MIRI با همکاری آژانس فضایی اروپا و آزمایشگاه پیش‌رانش جت ناسا طراحی شده‌است.
  • حسگر هدایت کامل / تصویربردار مادون‌قرمز نزدیک و طیف‌سنج بی‌لغزش (FGS/NIRISS)، که توسط آژانس فضایی کانادا طراحی و توسعه داده شده‌است، که می‌تواند طول موج‌های بین ۰٫۸ تا ۵ میکرومتر را مشاهده کند.

مقایسه با سایر تلسکوپ‌ها[ویرایش]

مقایسه با آینه اصلی هابل

تمایل به یک تلسکوپ مادون‌قرمز بزرگ به دهه‌ها قبل برمی‌گردد؛ در ایالات‌متحده آمریکا تلسکوپ مادون‌قرمز شاتل زمانی که شاتل فضایی در حال ساخت بود برنامه‌ریزی شد و به عنوان پتانسیل نجوم مادون‌قرمز اذعان شد. در مقایسه با تلسکوپ‌های زمینی، رصدخانه‌های فضایی عاری از جذب جوی نور مادون‌قرمز بودند.[۹]

بااین‌حال، تلسکوپ‌های مادون‌قرمز یک نقطه‌ضعف دارند - آن‌ها باید بسیار سرد بمانند و هرچه طول‌موج مادون‌قرمز طولانی‌تر شود، باید سردتر بمانند. در غیر این صورت، گرمای پس‌زمینه دستگاه به‌خودی‌خود ردیاب‌ها را تحت‌الشعاع قرار می‌دهد و باعث کور شدن آن می‌شود. برای غلبه بر این موضوع باید تلسکوپ را بسیار دقیق طراحی کرد، به‌طور خاص می‌توان تلسکوپ را داخل یک محفظه عایق حرارتی ذخیره‌سازی برودتی با ماده‌ای بسیار سرد، مانند هلیوم مایع، قرار داد. این بدان معناست که بیشتر تلسکوپ‌های مادون‌قرمز طول عمر محدودی متناسب با مادهٔ سردکنندهٔ آن‌ها دارند، به‌اندازهٔ چند ماه، شاید حداکثر چند سال. از طریق طراحی فضاپیما می‌توان دما را به‌اندازه کافی پایین نگه داشت تا مشاهدهٔ مادون‌قرمز نزدیک را بدون منبع خنک‌کننده انجام داد، مانند مأموریت‌های تلسکوپ فضایی اسپیتزر و کاوشگر نقشه‌بردار فروسرخ میدان وسیع. نمونهٔ دیگر، ابزار NICMOS هابل است که با استفاده از بلوک یخ نیتروژن که پس از چند سال تخلیه‌شده بود، شروع به کار کرد، اما سپس به کریوکلر تبدیل شد که به‌طور مداوم کار می‌کرد. جیمز وب طوری طراحی‌شده‌است که بتواند خودش را بدون وجود محفظهٔ عایق حرارتی ذخیره‌سازی برودتی، با استفاده از ترکیب سپر حرارتی و رادیاتور، سرد کند.

تأخیرها و افزایش هزینه‌های جیمز وب را می‌توان با تلسکوپ هابل مقایسه کرد. وقتی پروژه هابل به‌طور رسمی در سال ۱۹۷۲ شروع شد، پیش‌بینی می‌شد هزینهٔ ساخت ۳۰۰ میلیون دلاری داشته باشد (یا ۱ میلیارد دلار در سال ۲۰۰۶)، اما زمانی که به فضا فرستاده شد، هزینه‌ها چهار برابر شده بود. علاوه بر این، ابزارهای جدید و مأموریت‌های سرویس‌دهی تا سال ۲۰۰۶ هزینه را به حداقل ۹ میلیارد دلار در سال ۲۰۰۶ افزایش دادند.

تاریخچه[ویرایش]

سال تاریخ پرتاب بودجه

(میلیارد دلار)

۱۹۹۷ ۲۰۰۷ ۰٫۵
۱۹۹۸ ۲۰۰۷ ۱
۱۹۹۹ ۲۰۰۷ تا ۲۰۰۸ ۱
۲۰۰۰ ۲۰۰۹ ۱٫۸
۲۰۰۲ ۲۰۱۰ ۲٫۵
۲۰۰۳ ۲۰۱۱ ۲٫۵
۲۰۰۵ ۲۰۱۳ ۳
۲۰۰۶ ۲۰۱۴ ۴٫۵
۲۰۰۸ ۲۰۱۴ ۵٫۱
۲۰۱۰ ۲۰۱۵ تا ۲۰۱۶ ۶٫۵
۲۰۱۱ ۲۰۱۸ ۸٫۷
۲۰۱۳ ۲۰۱۸ ۸٫۸
۲۰۱۷ ۲۰۱۹ ۸٫۸
۲۰۱۸ ۲۰۲۰ ≥۸٫۸
۲۰۱۸ ۲۰۲۱ ۹٫۶۶
۲۰۲۰ ۲۰۲۱ ≥۱۰

پژوهش و توسعه[ویرایش]

کارهای اولیه برای توسعهٔ جانشینی برای هابل در خلال سال‌های ۱۹۸۹ و ۱۹۹۴ شد که منجر به مدل مفهومی از تلسکوپی به نام تلسکوپ نسل بعدی (NGST) بود که دیافراگم ۴ متری داشت و در مدار معادل با ۴ واحد نجومی کار می‌کرد. این فاصلهٔ مداری از غبار بین سیاره‌ای در امان بود. کار روی NGST در سال ۱۹۹۶ آغاز شد. این تلسکوپ در سال ۲۰۰۲، به خاطر نقش کلیدی جیمز ای. وب در پروژهٔ آپولو، به جیمز وب تغییر نام داد. JSWT حاصل همکاری آژانس فضایی ایالات متحدهٔ آمریکا و آژانس هوایی آمریکا با همکاری‌های بین‌المللی از سوی آژانس فضایی اروپا و آژانس فضایی کانادا است.

در دوران «سریع‌تر، بهتر و ارزان‌تر» در اواسط دههٔ ۱۹۹۰ رهبران ناسا به دنبال یک تلسکوپ فضایی کم‌هزینه بودند. نتیجهٔ طرح مفهومی NGST بود که دیافراگم ۸ متری داشت و در نقطهٔ L2 قرار داشت و تقریباً ۵۰۰ میلیون دلار تخمین زده شده بود. در سال ۱۹۹۷، ناسا با مرکز پروازهای فضایی گادرد، شرکت هوا فضا و فناوری بال (Ball) و شرکت TRW برای مطالعه‌هایی دربارهٔ نیازهای فنی و تخمین هزینه‌های این پروژه وارد همکاری شد و در سال ۱۹۹۹، لاکهید مارتین و TRW را برای مطالعات اولیه انتخاب کرد. پرتاب تلسکوپ در آن زمان برای سال ۲۰۰۷ برنامه‌ریزی شده بود اما تاریخ پرتاب متعاقباً بارها به تعویق افتاد (جدول روبرو را ببینید). در سال ۲۰۰۲، ناسا طی قراردادی ۸۲۴٫۸ میلیون دلار به TRW برای NGST، که اکنون به تلسکوپ فضایی جیمز وب تغییر نام یافته‌است، اعطا کرد. این قرارداد برای طرح یک آینه اصلی ۶٫۱ متری (۲۰ فوت) بود و تاریخ پرتاب سال ۲۰۱۰ انتخاب شد. در اواخر آن سال TRW توسط نورثروپ گرومن خریداری شد و به بخش فناوری فضایی این شرکت تبدیل شد.

مشکلات مربوط به هزینه و برنامه[ویرایش]

تلسکوپ فضایی جیمز وب دارای تاریخچهٔ هزینه‌ها و تأخیرهای بسیار زیاد است که به خاطر عوامل خارجی مانند تأخیر در تصمیم‌گیری در مورد موشک پرتاب و اضافه کردن بودجه‌ای به‌خاطر مسائل پیش‌بینی نشده. هزینهٔ پروژه در ابتدا ۱٫۶ میلیارد دلار پیش‌بینی شده بود، اما این پیش‌بینی در زمانی که ساخت تلسکوپ در سال ۲۰۰۸ شروع شد به ۵ میلیارد دلار رسیده بود. در تابستان سال ۲۰۱۰ مأموریت بررسی طراحی کلیهٔ موضوعات فنی با عالی‌ترین نمرات انجام شد، اما تغییر هزینه‌ها و زمان پرتاب باعث شد باربارا میکولسکی سناتور ایالت مریلند خواستار انجام تحقیقات مستقل در مورد این پروژه شد. کمیتهٔ مستقل بررسی جامع پروژه، دریافت که نزدیک‌ترین زمان ممکن برای پرتاب تلسکوپ می‌تواند اواخر سال ۲۰۱۵ با هزینهٔ اضافی ۱٫۵ میلیارد دلار (کلاً ۶٫۵ میلیارد دلار) باشد. آن‌ها همچنین خاطرنشان کردند که این امر، بودجهٔ پروژه را بالا برده و هر گونه تأخیر در پرتاب تلسکوپ باعث بالا رفتن هزینهٔ کل پروژه می‌شود.

برخورد ریزشهاب‌سنگ[ویرایش]

قطعهٔ آینه‌ای C3؛ در حلقه بیرونی از قطعات ۱۸ گانهٔ آینهٔ جیمز وب (از رو به رو ساعت ۵ در صفحه ساعت عقربه‌ای ۱۲ ساعته)، در اثر برخورد با یک ریزشهاب‌سنگ آسیب دید.[۱۰]این بخش از آینه بین ۲۳ تا ۲۵ مه، پنجمین و بزرگ‌ترین ضربه از زمان پرتاب بود، که در ۸ ژوئن ۲۰۲۲ گزارش شد، احتمالاً ضربه ریزشهاب‌سنگ از یک توده ذرات بزرگ گرد و غبار شد که مهندسین پروژه با استفاده از «فعال کننده آینه» ضربه را جبران کردند.[۱۱] گزارش دیگری نشان می‌دهد که آسیب واردشده به این تلسکوپ احتمالاً بیشتر از آن چیزی است که پیشتر تصور می‌شد. دانشمندان گزارش داده‌اند که آسیب واردشده که در اواخر ماه مه ۲۰۲۲ پیش آمده بود، ممکن است بدتر از آن چیزی باشد که پیشتر تصور می‌شد. گروهی از دانشمندان در مقاله جدیدی که در پی انتشار نخستین تصاویر باورنکردنی جیمز وب به چاپ رسید، عملکرد این تلسکوپ فضایی را در مرحله راه‌اندازی آن تشریح کردند. آنها مشکلاتی را گزارش دادند و خاطرنشان کردند که نمی‌توان آنها را اصلاح کرد. همچنین، دانشمندان متذکر شدند که این مشکلات، اثر کوچکی بر توان عملیاتی تلسکوپ دارد که هنوز قابل اندازه‌گیری نیست.[۱۲]

همکاران[ویرایش]

ناسا، با مشارکت آژانس فضایی اروپا ESA و آژانس فضایی کانادا CSA از سال ۱۹۹۶ در ساخت این تلسکوپ با یکدیگر همکاری کرده‌اند. مشارکت ESA در ساخت و پرتاب توسط اعضای آن در سال ۲۰۰۳ تأیید شد و توافق‌نامه‌ای بین ESA و ناسا در سال ۲۰۰۷ در این مورد به امضا رسید. در ازای مشارکت کامل، نمایندگی حضور و دسترسی به رصدخانه برای اخترشناسان خود، ESA ابزار NIRSpec، مونتاژ نیمکت نوری ابزار MIRI، یک پرتابگر آریان ۵ ECA و نیروی انسانی برای پشتیبانی از عملیات را ارائه می‌کند.[۱۳][۱۴] CSA حسگر هدایت دقیق و طیف‌نگار MIRI «ابزار مادون قرمز میانی» به همراه نیروی انسانی را برای پشتیبانی از عملیات فراهم می‌کند.[۱۵]

چندین هزار دانشمند، مهندس و تکنسین در ۱۵ کشور در پروژهٔ جیمزوب مشارکت داشته‌اند.[۱۶] در مجموع ۲۵۸ شرکت، سازمان دولتی و مؤسسهٔ دانشگاهی در این پروژه مشارکت دارند که ۱۴۲ از ایالات متحده، ۱۰۴ از ۱۲ کشور اروپایی، و ۱۲ از کانادا بوده‌اند.[۱۶]

کشورهای شرکت‌کننده[ویرایش]

مأموریت[ویرایش]

تلسکوپ فضایی جیمز وب چهار هدف کلیدی دارد:

این هدف‌ها را می‌توان با مشاهده در نور مادون قرمز نزدیک؛ به جای نور در قسمت مرئی طیف، به گونهٔ مؤثرتری انجام داد. به همین دلیل، ابزارهای آن نور مرئی یا فرابنفش را مانند تلسکوپ هابل اندازه‌گیری نمی‌کنند، ولی ظرفیت بسیار بیشتری برای انجام اخترشناسی فروسرخ خواهند داشت. این تلسکوپ به طیفی از طول موج‌ها از ۰٫۶ (نور نارنجی) تا ۲۸ میکرومتر (تابش بروسرخ عمیق در حدود «100 کلوین» (۱۷۳- درجه سانتیگراد؛ ۲۸۰ درجه فارنهایت) حساس است خواهد بود.

از تلسکوپ جیمز وب ممکن است برای جمع‌آوری اطلاعات در مورد ستارهٔ نور کم‌نور «تابی» کی‌ای‌سی ۸۴۶۲۸۵۲، که در سال ۲۰۱۵ کشف شد و دارای برخی ویژگی‌های غیرعادی منحنی نور است، استفاده شود.[۱۸] این تلسکوپ توسط موشک آریان ۵، در شهر گویان فرانسه با موفقیت پرتاب شد.

راه‌اندازی و طول مأموریت[ویرایش]

پرواز وی‌ای۲۵۶ آریان پروازی بود که تلسکوپ فضایی جیمز وب را در ۲۵ دسامبر ۲۰۲۱ به فضا پرتاب کرد[۱۹] که دویست و پنجاه و ششمین مأموریت آریان بود.

پرتاب برابر برنامه در ۲۵ دسامبر ۲۰۲۱ بر روی یک پرتابگر آریان ۵ از مرکز فضایی گویان در گویان فرانسه انجام شد.[۱۹] پس از پرتاب موفقیت‌آمیز، بیل نلسون، مدیر ناسا، آن را «روزی عالی برای سیاره زمین» نامید.[۲۰] تلسکوپ به خودی خود با رسیدن مدار قابل استفاده نیست و فضانوردان نیز نمی‌توانند مانند تلسکوپ هابل مأموریتی مانند تعویض ابزار را روی آن انجام دهند ولی حلقهٔ آدابتور اتصالی که جیمز وب به موشک متصل می‌کرد هنوز می‌تواند توسط یک فضاپیمای آینده در اتصال با رصدخانه برای رفع مشکلات آشکاری استفاده شود.[۲۱] این تلسکوپ ۲۷ دقیقه و ۷ ثانیه پس از پرتاب از موشک پرتابگر خود رها شد و یک تنظیم حدود ۳۰ روزه مداری آغاز شد که تلسکوپ را در مدار نقطه لاگرانژی L2 قرار می‌دهد. از آنجا که رصدخانه باید بتواند زیر رانش خفیف را جبران کند، این پرواز شامل سه اصلاح مسیر برنامه‌ریزی شده‌است، اما نه از رانش خفیف (شفاف خورشید، که باید بین تلسکوپ و خورشید باقی بماند و از چرخش برای کاهش سرعت جلوگیری کند)، بنابراین در بیشتر مسیر پرواز سرعتی کمتر از سرعت پایانی از سرعت نهایی برای مدار داشت.[۲۲]

زمان مأموریت اسمی تلسکوپ پنج سال با هدف ده سال است.[۲۳] مأموریت علمی پنج‌سالهٔ برنامه‌ریزی‌شده پس از یک مرحلهٔ راه‌اندازی شش‌ماهه آغاز می‌شود.[۲۴] جیمز وب به استفاده از پیشرانه برای حفظ مدار هالهٔ خود در اطراف L2 نیاز دارد، که حد بالا برای طول عمر طراحی شدهٔ آن را فراهم می‌کند، و این برای حمل کافی برای ده سال طراحی شده‌است.[۲۴] مدار L2 ناپایدار است، بنابراین نیاز به نگهداری موقعیت مداری خود برای جلوگیری از دور شدن تلسکوپ از پیکربندی مداری آن دارد.[۲۵] تلسکوپ جیمز وب از اولین عکس‌های خود را که از لنزهای دوربینش است،منتشر کرده‌است.

نگارخانه[ویرایش]

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جستارهای وابسته[ویرایش]

منابع[ویرایش]

  • Lallo, Matthew D. (2012). "Experience with the Hubble Space Telescope: 20 years of an archetype". Optical Engineering. 51 (1): 011011–011011–19. arXiv:1203.0002. Bibcode:2012OptEn..51a1011L. doi:10.1117/1.OE.51.1.011011. S2CID 15722152.
  • "A Deeper Sky | by Brian Koberlein". briankoberlein.com.
  • "FAQ for Scientists Webb Telescope/NASA". jwst.nasa.gov.
  • Shelton, Jim (3 March 2016). "Shattering the cosmic distance record, once again". دانشگاه ییل. Retrieved 4 March 2016.
  • "Hubble breaks cosmic distance record". SpaceTelescope.org. 3 March 2016. heic1604. Retrieved 3 March 2016.
  • Atkinson, Nancy. "Hubble Has Looked Back in Time as Far as It Can And Still Can't Find The First Stars". Universe Today – via ScienceAlert.
  • "L2 Orbit". Space Telescope Science Institute. Archived from the original on 3 February 2014. Retrieved 28 August 2016.
  • Clery, Daniel (27 March 2018). "NASA announces more delays for giant space telescope". Science. Retrieved 5 June 2018.
  • "JWST Wavefront Sensing and Control". Space Telescope Science Institute. Archived from the original on 5 August 2012. Retrieved 9 June 2011.

پانویس[ویرایش]

  1. ۱٫۰ ۱٫۱ "NASA JWST "Who are the partners in the Webb project?"". NASA. Retrieved 18 November 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ۲٫۰ ۲٫۱ Kelso, Thomas S. (25 December 2021). "JWST". Celestrak. Celestrak. Retrieved 26 December 2021.
  3. Clark, Stephen [@StephenClark1] (23 December 2021). "The exact launch mass of the James Webb Space Telescope: 6161.4 kilograms. That figure includes 167.5 kg of hydrazine and 132.5 kg of dinitrogen tetroxide for the propulsion system" (Tweet). Retrieved 23 December 2021 – via Twitter.
  4. "JWST Orbit". JWST User Documentation. Space Telescope Science Institute. Retrieved 25 December 2021.
  5. "James Webb Space Telescope". ESA eoPortal. Retrieved 29 June 2015.[عدم مطابقت با منبع]
  6. "JWST Telescope". James Webb Space Telescope User Documentation. Space Telescope Science Institute. 23 December 2019. Retrieved 11 June 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  7. تلسکوپ جیمز وب چیست
  8. «مهندسی بی‌نهایت: تلسکوپ فضایی جیمز وب؛ نگاهی به وسعت کیهان». زومیت. بایگانی‌شده از اصلی در ۲۱ ژوئن ۲۰۱۹. دریافت‌شده در ۲۱ ژوئن ۲۰۱۹.
  9. «مقایسه تلسکوپ Hubble و James Webb». gelxy.com. دریافت‌شده در ۲۰۲۱-۱۰-۲۴.
  10. Sutherland, Scott (10 June 2022). "Webb's primary mirror was just hit by a meteoroid, but it was built to endure". The Weather Network. Archived from the original on 9 June 2022. Retrieved 10 June 2022.
  11. Harwood, William (9 June 2022). "Webb telescope still performing well after micrometeoroid impact on mirror segment, NASA says". CBS News. Archived from the original on 9 June 2022. Retrieved 10 June 2022.
  12. «آسیب جدی به تلسکوپ "جیمز وب" در اثر برخورد با ریزشهاب‌سنگ». کشف اسرار کیهان با جیمز وب. دریافت‌شده در ۲۰۲۲-۰۷-۲۰.
  13. خطای یادکرد: خطای یادکرد:برچسب <ref>‎ غیرمجاز؛ متنی برای یادکردهای با نام ESA Media Relations Service وارد نشده‌است. (صفحهٔ راهنما را مطالعه کنید.).
  14. "ESA Science & Technology - Europe's Contributions to the JWST Mission". sci.esa.int.
  15. Canadian Space Agency "Eyes" Hubble's Successor: Canada Delivers its Contribution to the World's Most Powerful Space Telescope – Canadian Space Agency
  16. ۱۶٫۰ ۱۶٫۱ Jenner, Lynn (1 June 2020). "NASA's Webb Telescope is an International Endeavor". NASA. Retrieved 23 September 2021.
  17. Maggie Masetti; Anita Krishnamurthi (2009). "JWST Science". NASA. Retrieved 14 April 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  18. "NASA's Next Telescope Could ID Alien Megastructures". 9 February 2016. Retrieved 1 September 2016.
  19. ۱۹٫۰ ۱۹٫۱ خطای یادکرد: خطای یادکرد:برچسب <ref>‎ غیرمجاز؛ متنی برای یادکردهای با نام AS-20211225 وارد نشده‌است. (صفحهٔ راهنما را مطالعه کنید.).
  20. Overbye, Dennis; Roulette, Joey (2021-12-25). "James Webb Space Telescope Launches on Journey to See the Dawn of Starlight". The New York Times. ISSN 0362-4331. Retrieved 2021-12-25.
  21. خطای یادکرد: خطای یادکرد:برچسب <ref>‎ غیرمجاز؛ متنی برای یادکردهای با نام howBig وارد نشده‌است. (صفحهٔ راهنما را مطالعه کنید.).
  22. -NASA blog, first mid-flight correction
  23. "About the Webb". NASA James Webb Space Telescope. 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  24. ۲۴٫۰ ۲۴٫۱ "Frequently asked questions: How long will the Webb mission last?". NASA James Webb Space Telescope. 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  25. "JWST Orbit". James Webb Space Telescope User Documentation. Retrieved 8 September 2021.

پیوند به بیرون[ویرایش]

James Webb Space Telescope
JWST spacecraft model 3.png
Rendering of the James Webb Space Telescope fully deployed.
NamesNext Generation Space Telescope (NGST; 1996–2002)
Mission typeAstronomy
OperatorSTScI (NASA)[1] / ESA / CSA
COSPAR ID2021-130A Edit this at Wikidata
SATCAT no.50463[2]
WebsiteOfficial website
Mission duration
  • 7 months, 18 days (elapsed)
  • 5+12 years (primary mission)[3]
  • 10 years (planned)
  • 20 years (expected life)[4]
Spacecraft properties
Manufacturer
Launch mass6,161.4 kg (13,584 lb)[5]
Dimensions20.197 m × 14.162 m (66.26 ft × 46.46 ft), sunshield
Power2 kW
Start of mission
Launch date25 December 2021 (2021-12-25), 12:20 UTC
RocketAriane 5 ECA (VA256)
Launch siteCentre Spatial Guyanais, ELA-3
ContractorArianespace
Entered service12 July 2022
Orbital parameters
Reference systemSun–Earth L2 orbit
RegimeHalo orbit
Periapsis altitude250,000 km (160,000 mi)[6]
Apoapsis altitude832,000 km (517,000 mi)[6]
Period6 months
Main telescope
TypeKorsch telescope
Diameter6.5 m (21 ft)
Focal length131.4 m (431 ft)
Focal ratiof/20.2
Collecting area25.4 m2 (273 sq ft)[7]
Wavelengths0.6–28.3 μm (orange to mid-infrared)
Transponders
Band
Bandwidth
  • S-band up: 16 kbit/s
  • S-band down: 40 kbit/s
  • Ka-band down: up to 28 Mbit/s
Instruments
Elements
JWST Launch Logo.png
James Webb Space Telescope mission logo  

The James Webb Space Telescope (JWST) is a space telescope designed primarily to conduct infrared astronomy. As the largest optical telescope in space, its greatly improved infrared resolution and sensitivity allow it to view objects too early, distant, or faint for the Hubble Space Telescope. This is expected to enable a broad range of investigations across the fields of astronomy and cosmology, such as observation of the first stars and the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.[8]

The U.S. National Aeronautics and Space Administration (NASA) led JWST's development in collaboration with the European Space Agency (ESA) and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center (GSFC) in Maryland managed telescope development, the Space Telescope Science Institute in Baltimore on the Homewood Campus of Johns Hopkins University operates JWST, and the prime contractor was Northrop Grumman. The telescope is named after James E. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs.

The James Webb Space Telescope was launched on 25 December 2021 on an Ariane 5 rocket from Kourou, French Guiana, and arrived at the Sun–Earth L2 Lagrange point in January 2022. The first image from JWST was released to the public via a press conference on 11 July 2022.[9] The telescope is the successor of the Hubble as NASA's flagship mission in astrophysics.

JWST's primary mirror consists of 18 hexagonal mirror segments made of gold-plated beryllium, which combined create a 6.5-meter-diameter (21 ft) mirror, compared with Hubble's 2.4 m (7 ft 10 in). This gives JWST a light-collecting area of about 25 square meters, about six times that of Hubble. Unlike Hubble, which observes in the near ultraviolet and visible (0.1 to 0.8 μm), and near infrared (0.8–2.5 μm)[10] spectra, JWST observes in a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm). The telescope must be kept extremely cold, below 50 K (−223 °C; −370 °F), such that the infrared light emitted by the telescope itself does not interfere with the collected light. It is deployed in a solar orbit near the Sun–Earth L2 Lagrange point, about 1.5 million kilometers (930,000 mi) from Earth, where its five-layer sunshield protects it from warming by the Sun, Earth, and Moon.

Initial designs for the telescope, then named the Next Generation Space Telescope, began in 1996. Two concept studies were commissioned in 1999, for a potential launch in 2007 and a US$1 billion budget. The program was plagued with enormous cost overruns and delays; a major redesign in 2005 led to the current approach, with construction completed in 2016 at a total cost of US$10 billion. The high-stakes nature of the launch and the telescope's complexity were remarked upon by the media, scientists, and engineers.

Features

The James Webb Space Telescope has a mass that is about half of Hubble Space Telescope's mass. The JWST has a 6.5-meter (21 ft)-diameter gold-coated beryllium primary mirror made up of 18 separate hexagonal mirrors. The mirror has a polished area of 26.3 m2 (283 sq ft), of which 0.9 m2 (9.7 sq ft) is obscured by the secondary support struts,[11] giving a total collecting area of 25.4 m2 (273 sq ft). This is over six times larger than the collecting area of Hubble's 2.4-meter (7.9 ft) diameter mirror, which has a collecting area of 4.0 m2 (43 sq ft). The mirror has a gold coating to provide infrared reflectivity and this is covered by a thin layer of glass for durability.[12]

JWST is designed primarily for near-infrared astronomy, but can also see orange and red visible light, as well as the mid-infrared region, depending on the instrument.[8] It can detect objects up to 100 times fainter than Hubble can, and objects much earlier in the history of the universe, back to redshift z≈20 (about 180 million years cosmic time after the Big Bang).[13] For comparison, the earliest stars are thought to have formed between z≈30 and z≈20 (100–180 million years cosmic time),[14] and the first galaxies may have formed around redshift z≈15 (about 270 million years cosmic time). Hubble is unable to see further back than very early reionization[15][16] at about z≈11.1 (galaxy GN-z11, 400 million years cosmic time).[17][18][13]

The design emphasizes the near to mid-infrared for several reasons:

  • high-redshift (very early and distant) objects have their visible emissions shifted into the infrared, and therefore their light can be observed today only via infrared astronomy;[10]
  • infrared light passes more easily through dust clouds than visible light[10]
  • colder objects such as debris disks and planets emit most strongly in the infrared;
  • these infrared bands are difficult to study from the ground or by existing space telescopes such as Hubble.
Rough plot of Earth's atmospheric absorption (or opacity) to various wavelengths of electromagnetic radiation, including visible light

Ground-based telescopes must look through Earth's atmosphere, which is opaque in many infrared bands (see figure at right). Even where the atmosphere is transparent, many of the target chemical compounds, such as water, carbon dioxide, and methane, also exist in the Earth's atmosphere, vastly complicating analysis. Existing space telescopes such as Hubble cannot study these bands since their mirrors are insufficiently cool (the Hubble mirror is maintained at about 15 °C [288 K; 59 °F]) which means that the telescope itself radiates strongly in the relevant infrared bands.[19]

JWST can also observe objects in the Solar System at an angle of more than 85° from the Sun and having an apparent angular rate of motion less than 0.03 arc seconds per second.[a] This includes Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, their satellites, and comets, asteroids and minor planets at or beyond the orbit of Mars. JWST has the near-IR and mid-IR sensitivity to be able to observe virtually all known Kuiper Belt Objects.[14][22] In addition, it can observe opportunistic and unplanned targets within 48 hours of a decision to do so, such as supernovae and gamma ray bursts.[14]

Location and orbit

JWST operates in a halo orbit, circling around a point in space known as the Sun–Earth L2 Lagrange point, approximately 1,500,000 km (930,000 mi) beyond Earth's orbit around the Sun. Its actual position varies between about 250,000 and 832,000 km (155,000–517,000 mi) from L2 as it orbits, keeping it out of both Earth and Moon's shadow. By way of comparison, Hubble orbits 550 km (340 mi) above Earth's surface, and the Moon is roughly 400,000 km (250,000 mi) from Earth. Objects near this Sun–Earth L2 point can orbit the Sun in synchrony with the Earth, allowing the telescope to remain at a roughly constant distance[23] with continuous orientation of its unique sunshield and equipment bus toward the Sun, Earth and Moon. Combined with its wide shadow-avoiding orbit, the telescope can simultaneously block incoming heat and light from all three of these bodies and avoid even the smallest changes of temperature from Earth and Moon shadows that would affect the structure, yet still maintain uninterrupted solar power and Earth communications on its sun-facing side. This arrangement keeps the temperature of the spacecraft constant and below the 50 K (−223 °C; −370 °F) necessary for faint infrared observations.[24][25]

Sunshield protection

Test unit of the sunshield stacked and expanded at the Northrop Grumman facility in California, 2014

To make observations in the infrared spectrum, JWST must be kept under 50 K (−223.2 °C; −369.7 °F); otherwise, infrared radiation from the telescope itself would overwhelm its instruments. Its large sunshield blocks light and heat from the Sun, Earth, and Moon, and its position near the Sun–Earth L2 keeps all three bodies on the same side of the spacecraft at all times.[26] Its halo orbit around the L2 point avoids the shadow of the Earth and Moon, maintaining a constant environment for the sunshield and solar arrays.[23] The resulting stable temperature for the structures on the dark side is critical to maintaining precise alignment of the primary mirror segments.[24]

The five-layer sunshield, each layer as thin as a human hair,[27] is made of Kapton E film, coated with aluminum on both sides and a layer of doped silicon on the Sun-facing side of the two hottest layers to reflect the Sun's heat back into space.[24] Accidental tears of the delicate film structure during deployment testing in 2018 led to further delays to the telescope.[28]

The sunshield was designed to be folded twelve times (concertina style) so that it fit within the Ariane 5 rocket's payload fairing, which is 4.57 m (15.0 ft) in diameter, and 16.19 m (53.1 ft) long. The shield's fully deployed dimensions were planned as 14.162 m × 21.197 m (46.46 ft × 69.54 ft).[29]

Keeping within the shadow of the sunshield limits the field of regard of JWST at any given time. The telescope can see 40 percent of the sky from any one position, but can see all of the sky over a period of six months.[30]

Optics

Main mirror assembly from the front with primary mirrors attached, November 2016
Diffraction spikes due to mirror segments and spider color-coded

JWST's primary mirror is a 6.5 m (21 ft)-diameter gold-coated beryllium reflector with a collecting area of 25.4 m2 (273 sq ft). If it had been designed as a single large mirror, it would have been too large for existing launch vehicles. The mirror is therefore composed of 18 hexagonal segments (a technique pioneered by Guido Horn d'Arturo), which unfolded after the telescope was launched. Image plane wavefront sensing through phase retrieval is used to position the mirror segments in the correct location using very precise micro-motors. Subsequent to this initial configuration, they only need occasional updates every few days to retain optimal focus.[31] This is unlike terrestrial telescopes, for example the Keck telescopes, which continually adjust their mirror segments using active optics to overcome the effects of gravitational and wind loading.[32] The Webb telescope uses 132 small motors (called actuators) to position and occasionally adjust the optics.[33] The actuators can position the mirror with 10 nanometer accuracy.[34]

JWST's optical design is a three-mirror anastigmat,[35] which makes use of curved secondary and tertiary mirrors to deliver images that are free from optical aberrations over a wide field. The secondary mirror is 0.74 m (2.4 ft) in diameter. In addition, there is a fine steering mirror which can adjust its position many times per second to provide image stabilization. Photographs taken by the JWST have six spikes plus two fainter ones due to the spider supporting the secondary mirror.[36]

Scientific instruments

NIRCam wrapped up in 2013
The Calibration Assembly, one component of the NIRSpec instrument
MIRI

The Integrated Science Instrument Module (ISIM) is a framework that provides electrical power, computing resources, cooling capability as well as structural stability to the Webb telescope. It is made with bonded graphite-epoxy composite attached to the underside of Webb's telescope structure. The ISIM holds the four science instruments and a guide camera.[37]

  • NIRCam (Near Infrared Camera) is an infrared imager which has spectral coverage ranging from the edge of the visible (0.6 μm) through to the near infrared (5 μm).[38][39] There are 10 sensors each of 4 megapixels. NIRCam serves as the observatory's wavefront sensor, which is required for wavefront sensing and control activities, used to align and focus the main mirror segments. NIRCam was built by a team led by the University of Arizona, with principal investigator Marcia J. Rieke.[40]
  • NIRSpec (Near Infrared Spectrograph) performs spectroscopy over the same wavelength range. It was built by the European Space Agency at ESTEC in Noordwijk, Netherlands. The leading development team includes members from Airbus Defence and Space, Ottobrunn and Friedrichshafen, Germany, and the Goddard Space Flight Center; with Pierre Ferruit (École normale supérieure de Lyon) as NIRSpec project scientist. The NIRSpec design provides three observing modes: a low-resolution mode using a prism, an R~1000 multi-object mode, and an R~2700 integral field unit or long-slit spectroscopy mode. Switching of the modes is done by operating a wavelength preselection mechanism called the Filter Wheel Assembly, and selecting a corresponding dispersive element (prism or grating) using the Grating Wheel Assembly mechanism. Both mechanisms are based on the successful ISOPHOT wheel mechanisms of the Infrared Space Observatory. The multi-object mode relies on a complex micro-shutter mechanism to allow for simultaneous observations of hundreds of individual objects anywhere in NIRSpec's field of view. There are two sensors each of 4 megapixels.[41]
  • MIRI (Mid-Infrared Instrument) measures the mid-to-long-infrared wavelength range from 5 to 27 μm.[42][43] It contains both a mid-infrared camera and an imaging spectrometer.[44] MIRI was developed as a collaboration between NASA and a consortium of European countries, and is led by George Rieke (University of Arizona) and Gillian Wright (UK Astronomy Technology Centre, Edinburgh, Scotland).[40] The temperature of the MIRI must not exceed 6 K (−267 °C; −449 °F): a helium gas mechanical cooler sited on the warm side of the environmental shield provides this cooling.[45]
  • FGS/NIRISS (Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph), led by the Canadian Space Agency under project scientist John Hutchings (Herzberg Astronomy and Astrophysics Research Centre), is used to stabilize the line-of-sight of the observatory during science observations. Measurements by the FGS are used both to control the overall orientation of the spacecraft and to drive the fine steering mirror for image stabilization. The Canadian Space Agency also provided a Near Infrared Imager and Slitless Spectrograph (NIRISS) module for astronomical imaging and spectroscopy in the 0.8 to 5 μm wavelength range, led by principal investigator René Doyon at the Université de Montréal.[40] Although they are often referred together as a unit, the NIRISS and FGS serve entirely different purposes, with one being a scientific instrument and the other being a part of the observatory's support infrastructure.[46]

NIRCam and MIRI feature starlight-blocking coronagraphs for observation of faint targets such as extrasolar planets and circumstellar disks very close to bright stars.[43]

Spacecraft bus

Diagram of the spacecraft bus. The solar panel is in green and the light purple panels are radiators.

The spacecraft bus is the primary support component of the James Webb Space Telescope, hosting a multitude of computing, communication, electric power, propulsion, and structural parts.[47] Along with the sunshield, it forms the spacecraft element of the space telescope.[48][49] The spacecraft bus is on the Sun-facing "warm" side of the sunshield and operates at a temperature of about 300 K (27 °C; 80 °F).[48]

The structure of the spacecraft bus has a mass of 350 kg (770 lb), and must support the 6,200 kg (13,700 lb) space telescope. It is made primarily of graphite composite material.[50] It was assembled in California, assembly was completed in 2015, and then it had to be integrated with the rest of the space telescope leading up to its 2021 launch. The spacecraft bus can rotate the telescope with a pointing precision of one arcsecond, and isolates vibration down to two milliarcseconds.[51]

Webb has two pairs of rocket engines (one pair for redundancy) to make course corrections on the way to L2 and for station keeping – maintaining the correct position in the halo orbit. Eight smaller thrusters are used for attitude control – the correct pointing of the spacecraft.[52] The engines use hydrazine fuel (159 liters or 42 U.S. gallons at launch) and dinitrogen tetroxide as oxidizer (79.5 liters or 21.0 U.S. gallons at launch).[53]

Servicing

JWST is not intended to be serviced in space. A crewed mission to repair or upgrade the observatory, as was done for Hubble, would not currently be possible,[54] and according to NASA Associate Administrator Thomas Zurbuchen, despite best efforts, an uncrewed remote mission was found to be beyond current technology at the time JWST was designed.[55] During the long JWST testing period, NASA officials referred to the idea of a servicing mission, but no plans were announced.[56][57] Since the successful launch, NASA has stated that nevertheless limited accommodation was made to facilitate future servicing missions. These accommodations included precise guidance markers in the form of crosses on the surface of JWST, for use by remote servicing missions, as well as refillable fuel tanks, removable heat protectors, and accessible attachment points.[58][55]

Comparison with other telescopes

Comparison with Hubble primary mirror
Primary mirror size comparison between JWST and Hubble

The desire for a large infrared space telescope traces back decades. In the United States, the Space Infrared Telescope Facility (later called the Spitzer Space Telescope) was planned while the Space Shuttle was in development, and the potential for infrared astronomy was acknowledged at that time.[59] Unlike ground telescopes, space observatories were free from atmospheric absorption of infrared light. Space observatories opened up a whole "new sky" for astronomers.

The tenuous atmosphere above the 400 km nominal flight altitude has no measurable absorption so that detectors operating at all wavelengths from 5 μm to 1000 μm can achieve high radiometric sensitivity.

— S. G. McCarthy and G. W. Autio, 1978.[59]

However, infrared telescopes have a disadvantage: they need to stay extremely cold, and the longer the wavelength of infrared, the colder they need to be. If not, the background heat of the device itself overwhelms the detectors, making it effectively blind. This can be overcome by careful spacecraft design, in particular by placing the telescope in a dewar with an extremely cold substance, such as liquid helium. The coolant will slowly vaporize, limiting the lifetime of the instrument from as short as a few months to a few years at most.[19]

In some cases, it is possible to maintain a temperature low enough through the design of the spacecraft to enable near-infrared observations without a supply of coolant, such as the extended missions of Spitzer Space Telescope and Wide-field Infrared Survey Explorer, which operated at reduced capacity after coolant depletion. Another example is Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument, which started out using a block of nitrogen ice that depleted after a couple of years, but was then replaced during the STS-109 servicing mission with a cryocooler that worked continuously. The James Webb Space Telescope is designed to cool itself without a dewar, using a combination of sunshields and radiators, with the mid-infrared instrument using an additional cryocooler.[60]

Selected space telescopes and instruments[61]
Name Launch year Wavelength
(μm)
Aperture
(m)
Cooling
Spacelab Infrared Telescope (IRT) 1985 1.7–118 0.15 Helium
Infrared Space Observatory (ISO)[62] 1995 2.5–240 0.60 Helium
Hubble Space Telescope Imaging Spectrograph (STIS) 1997 0.115–1.03 2.4 Passive
Hubble Near Infrared Camera and Multi-Object Spectrometer (NICMOS) 1997 0.8–2.4 2.4 Nitrogen, later cryocooler
Spitzer Space Telescope 2003 3–180 0.85 Helium
Hubble Wide Field Camera 3 (WFC3) 2009 0.2–1.7 2.4 Passive, and thermo-electric[63]
Herschel Space Observatory 2009 55–672 3.5 Helium
James Webb Space Telescope 2021 0.6–28.5 6.5 Passive, and cryocooler (MIRI)

JWST's delays and cost increases can be compared to those of its predecessor, the Hubble Space Telescope. When Hubble formally started in 1972, it had an estimated development cost of US$300 million (or about US$1 billion in 2006 constant dollars), but by the time it was sent into orbit in 1990, the cost was about four times that. In addition, new instruments and servicing missions increased the cost to at least US$9 billion by 2006.[64]

Development history

Background (development to 2003)

Major Milestones
Year Milestone
1996 Next Generation Space Telescope project first proposed (mirror size: 8 m)
2001 NEXUS Space Telescope, a precursor to the Next Generation Space Telescope, cancelled[65]
2002 Proposed project renamed James Webb Space Telescope, (mirror size reduced to 6 m)
2003 Northrop Grumman awarded contract to build telescope
2007 Memorandum of Understanding signed between NASA and ESA[66]
2010 Mission Critical Design Review (MCDR) passed
2011 Proposed cancel
2016 Final assembly completed
2021 Launch

Discussions of a Hubble follow-on started in the 1980s, but serious planning began in the early 1990s.[67] The Hi-Z telescope concept was developed between 1989 and 1994:[68] a fully baffled[b] 4 m (13 ft) aperture infrared telescope that would recede to an orbit at 3 Astronomical unit (AU).[69] This distant orbit would have benefited from reduced light noise from zodiacal dust.[69] Other early plans called for a NEXUS precursor telescope mission.[70][71]

Correcting the flawed optics of the Hubble Space Telescope in its first years played a significant role in the birth of the JWST. In 1993, NASA readied STS-61, the Space Shuttle mission that would carry a replacement for HST's camera and a retrofit for its imaging spectrograph to compensate for the spherical aberration in its primary mirror. While the astronomical community eagerly awaited this mission, NASA cautioned that this extraordinary advance in working in space carried significant risk and that its successful completion was in no way guaranteed.

Consequently, the HST & Beyond Committee was formed in 1995 to evaluate the effectiveness of the HST repair mission and to explore ideas for future space telescopes that would be needed if the repair mission fell short.[72] It had the good fortune to see the success of the Space Shuttle Servicing Mission 1 in December 1993 and the unprecedented public response to the stunning images that the HST delivered.

Emboldened by HST's success, and recognizing innovative work in Europe for future missions[73][74] its 1996 report explored the concept of a larger and much colder, infrared-sensitive telescope that could reach back in cosmic time to the birth of the first galaxies. This high-priority science goal was beyond the HST's capability because, as a warm telescope, it is blinded by infrared emission from its own optical system. In addition to recommendations to extend the HST mission to 2005 and to develop technologies for finding planets around other stars, NASA embraced the chief recommendation of HST & Beyond[75] for a large, cold space telescope (radiatively cooled far below 0 °C), and began the planning process for the future JWST.

Beginning in the 1960s, and at the beginning of each decade since, the National Academies had organized the community of U.S. astronomers to think creatively about astronomical instruments and research for the subsequent decade, and to reach consensus on goals and priorities. A faithful supporter of these Decadal Surveys of Astronomy and Astrophysics, NASA has also been extraordinarily successful in developing programs and tools to accomplish survey recommendations. So, even with the substantial support and excitement in the mid-1990s for NASA's beginning to work on a successor to the HST, the astronomical community regarded a high prioritization by the 2000 Decadal Survey as essential.

Preparation for the Survey included further development of the scientific program for what became known as the Next Generation Space Telescope,[76] and advancements in relevant technologies by NASA. As it matured, studying the birth of galaxies in the young universe, and searching for planets around other stars – the prime goals coalesced as "Origins" by HST & Beyond became prominent.

Late in the 1990s NASA created the Origins Subcommittee to guide this effort and the Beyond Einstein Subcommittee to oversee missions where the universe is a laboratory for fundamental astrophysics, for example, black holes and supernovae. As hoped, the NGST received the highest ranking in the 2000 Decadal Survey of Astronomy & Astrophysics,[77] which allowed the project to proceed with the full endorsement of a community consensus.

An administrator of NASA, Dan Goldin, coined the phrase "faster, better, cheaper", and opted for the next big paradigm shift for astronomy, namely, breaking the barrier of a single mirror. That meant going from "eliminate moving parts" to "learn to live with moving parts" (i.e. segmented optics). With the goal to reduce mass density tenfold, silicon carbide with a very thin layer of glass on top was first looked at, but beryllium was selected at the end.[67]

The mid-1990s era of "faster, better, cheaper" produced the NGST concept, with an 8 m (26 ft) aperture to be flown to L2, roughly estimated to cost US$500 million.[78] In 1997, NASA worked with the Goddard Space Flight Center,[79] Ball Aerospace & Technologies,[80] and TRW[81] to conduct technical requirement and cost studies of the three different concepts, and in 1999 selected Lockheed Martin[82] and TRW for preliminary concept studies.[83] Launch was at that time planned for 2007, but the launch date was pushed back many times (see table further down).

In 2002, the project was renamed after NASA's second administrator (1961–1968), James E. Webb (1906–1992).[84] Webb led the agency during the Apollo program and established scientific research as a core NASA activity.[85]

In 2003, NASA awarded TRW the US$824.8 million prime contract for JWST. The design called for a de-scoped 6.1 m (20 ft) primary mirror and a launch date of 2010.[86] Later that year, TRW was acquired by Northrop Grumman in a hostile bid and became Northrop Grumman Space Technology.[83]

Early development and replanning (2003–2007)

Early full-scale model on display at NASA Goddard Space Flight Center (2005)

Development was managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, with John C. Mather as its project scientist. The primary contractor was Northrop Grumman Aerospace Systems, responsible for developing and building the spacecraft element, which included the satellite bus, sunshield, Deployable Tower Assembly (DTA) which connects the Optical Telescope Element to the spacecraft bus, and the Mid Boom Assembly (MBA) which helps to deploy the large sunshields on orbit,[87] while Ball Aerospace & Technologies has been subcontracted to develop and build the OTE itself, and the Integrated Science Instrument Module (ISIM).[37]

Cost growth revealed in spring 2005 led to an August 2005 re-planning.[88] The primary technical outcomes of the re-planning were significant changes in the integration and test plans, a 22-month launch delay (from 2011 to 2013), and elimination of system-level testing for observatory modes at wavelength shorter than 1.7 μm. Other major features of the observatory were unchanged. Following the re-planning, the project was independently reviewed in April 2006.

In the 2005 re-plan, the life-cycle cost of the project was estimated at US$4.5 billion. This comprised approximately US$3.5 billion for design, development, launch and commissioning, and approximately US$1.0 billion for ten years of operations.[88] The ESA agreed in 2004 to contributing about €300 million, including the launch.[89] The Canadian Space Agency pledged CA$39 million in 2007[90] and in 2012 delivered its contributions in equipment to point the telescope and detect atmospheric conditions on distant planets.[91]

Detailed design and construction (2007–2021)

A JWST mirror segment, 2010
Mirror segments undergoing cryogenic tests at the X-ray & Cryogenic Facility at Marshall Space Flight Center
The assembled telescope following environmental testing

In January 2007, nine of the ten technology development items in the project successfully passed a Non-Advocate Review.[92] These technologies were deemed sufficiently mature to retire significant risks in the project. The remaining technology development item (the MIRI cryocooler) completed its technology maturation milestone in April 2007. This technology review represented the beginning step in the process that ultimately moved the project into its detailed design phase (Phase C). By May 2007, costs were still on target.[93] In March 2008, the project successfully completed its Preliminary Design Review (PDR). In April 2008, the project passed the Non-Advocate Review. Other passed reviews include the Integrated Science Instrument Module review in March 2009, the Optical Telescope Element review completed in October 2009, and the Sunshield review completed in January 2010.[94]

In April 2010, the telescope passed the technical portion of its Mission Critical Design Review (MCDR). Passing the MCDR signified the integrated observatory can meet all science and engineering requirements for its mission.[95] The MCDR encompassed all previous design reviews. The project schedule underwent review during the months following the MCDR, in a process called the Independent Comprehensive Review Panel, which led to a re-plan of the mission aiming for a 2015 launch, but as late as 2018. By 2010, cost over-runs were impacting other projects, though JWST itself remained on schedule.[96]

By 2011, the JWST project was in the final design and fabrication phase (Phase C). As is typical for a complex design that cannot be changed once launched, there are detailed reviews of every portion of design, construction, and proposed operation. New technological frontiers were pioneered by the project, and it passed its design reviews. In the 1990s it was unknown if a telescope so large and of such low mass was possible.[97]

Assembly of the hexagonal segments of the primary mirror, which was done via robotic arm, began in November 2015 and was completed on 3 February 2016. The secondary mirror was installed on 3 March 2016.[98][99] Final construction of the Webb telescope was completed in November 2016, after which extensive testing procedures began.[100]

In March 2018, NASA delayed JWST's launch an additional 2 years to May 2020 after the telescope's sunshield ripped during a practice deployment and the sunshield's cables did not sufficiently tighten. In June 2018, NASA delayed the launch by an additional 10 months to March 2021, based on the assessment of the independent review board convened after the failed March 2018 test deployment.[101] The review identified that JWST launch and deployment had 344 potential single-point failures – tasks that had no alternative or means of recovery if unsuccessful, and therefore had to succeed for the telescope to work.[102] In August 2019, the mechanical integration of the telescope was completed, something that was scheduled to be done 12 years before in 2007.[103]

After construction was completed, JWST underwent final tests at a Northrop Grumman factory in Redondo Beach, California.[104] A ship carrying the telescope left California on 26 September 2021, passed through the Panama Canal, and arrived in French Guiana on 12 October 2021.[105]

Cost and schedule issues

NASA's lifetime cost for the project is expected to be US$9.7 billion, of which US$8.8 billion was spent on spacecraft design and development and US$861 million is planned to support five years of mission operations.[106] Representatives from ESA and CSA stated their project contributions amount to approximately €700 million and CA$200 million, respectively.[107]

A study in 1984 by the Space Science Board estimated that to build a next-generation infrared observatory in orbit would cost US$4 billion (US$7B in 2006 dollars, or $10B in 2020 dollars).[64] While this came close to the final cost of JWST, the first NASA design considered in the late 1990s was more modest, aiming for a $1 billion price tag over 10 years of construction. Over time this design expanded, added funding for contingencies, and had scheduling delays.

Then-planned launch and total budget
Year Planned
launch
Budget plan
(billion USD)
1998 2007[108] 1[64]
2000 2009[42] 1.8[64]
2002 2010[109] 2.5[64]
2003 2011[110] 2.5[64]
2005 2013 3[111]
2006 2014 4.5[112]
2008: Preliminary Design Review
2008 2014 5.1[113]
2010: Critical Design Review
2010 2015 to 2016 6.5[114]
2011 2018 8.7[115]
2017 2019[116] 8.8
2018 2020[117] ≥8.8
2019 March 2021[118] 9.66
2021 Dec 2021[119] 9.70

By 2008, when the project entered preliminary design review and was formally confirmed for construction, over US$1 billion had already been spent on developing the telescope, and the total budget was estimated at about US$5 billion (equivalent to $6.94 billion in 2021).[120] In summer 2010, the mission passed its Critical Design Review (CDR) with excellent grades on all technical matters, but schedule and cost slips at that time prompted Maryland U.S. Senator Barbara Mikulski to call for external review of the project. The Independent Comprehensive Review Panel (ICRP) chaired by J. Casani (JPL) found that the earliest possible launch date was in late 2015 at an extra cost of US$1.5 billion (for a total of US$6.5 billion). They also pointed out that this would have required extra funding in FY2011 and FY2012 and that any later launch date would lead to a higher total cost.[114]

On 6 July 2011, the United States House of Representatives' appropriations committee on Commerce, Justice, and Science moved to cancel the James Webb project by proposing an FY2012 budget that removed US$1.9 billion from NASA's overall budget, of which roughly one quarter was for JWST.[121][122][123][124] US$3 billion had been spent and 75% of its hardware was in production.[125] This budget proposal was approved by subcommittee vote the following day. The committee charged that the project was "billions of dollars over budget and plagued by poor management".[121] In response, the American Astronomical Society issued a statement in support of JWST,[126] as did Senator Mikulski.[127] A number of editorials supporting JWST appeared in the international press during 2011 as well.[121][128][129] In November 2011, Congress reversed plans to cancel JWST and instead capped additional funding to complete the project at US$8 billion.[130]

While similar issues had affected other major NASA projects such as the Hubble telescope, some scientists expressed concerns about growing costs and schedule delays for the Webb telescope, worrying that its budget might be competing with those of other space science programs.[131][132] A 2010 Nature article described JWST as "the telescope that ate astronomy".[133] NASA continued to defend the budget and timeline of the program to Congress.[132][134]

In 2018, Gregory L. Robinson was appointed as the new director of the Webb program.[135][135] Robinson was credited with raising the program's schedule efficiency (how many measures were completed on time) from 50% to 95%.[135] For his role in improving the performance of the Webb program, Robinsons's supervisor, Thomas Zurbuchen, called him "the most effective leader of a mission I have ever seen in the history of NASA."[135] In July 2022, after Webb's commissioning process was complete and it began transmitting its first data, Robinson retired following a 33-year career at NASA.[136]

On 27 March 2018, NASA pushed back the launch to May 2020 or later,[117] with a final cost estimate to come after a new launch window was determined with the European Space Agency (ESA).[137][138][139] In 2019, its mission cost cap was increased by US$800 million.[140] After launch windows were paused in 2020 due to the COVID-19 pandemic,[141] JWST was finally launched at the end of 2021, with a total budget of just under US$10 billion.

Partnership

NASA, ESA and CSA have collaborated on the telescope since 1996. ESA's participation in construction and launch was approved by its members in 2003 and an agreement was signed between ESA and NASA in 2007. In exchange for full partnership, representation and access to the observatory for its astronomers, ESA is providing the NIRSpec instrument, the Optical Bench Assembly of the MIRI instrument, an Ariane 5 ECA launcher, and manpower to support operations.[89][142] The CSA provided the Fine Guidance Sensor and the Near-Infrared Imager Slitless Spectrograph and manpower to support operations.[143]

Several thousand scientists, engineers, and technicians spanning 15 countries have contributed to the build, test and integration of the JWST.[144] A total of 258 companies, government agencies, and academic institutions participated in the pre-launch project; 142 from the United States, 104 from 12 European countries (including 21 from the U.K., 16 from France, 12 from Germany and 7 international[145]), and 12 from Canada.[144] Other countries as NASA partners, such as Australia, were involved in post-launch operation.[146]

Participating countries:

Controversy over name

In 2002, NASA administrator (2001–2004) Sean O'Keefe made the decision to name the telescope after James E. Webb, the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and much of the Apollo programs.[84][85]

In 2015, allegations surfaced around Webb's role in the lavender scare, the mid-20th-century persecution by the U.S. government targeting homosexuals in federal employment.[147][148] The scare led to the dismissal of nearly 300 U.S. State Department employees between 1950 and 1952; Webb served as undersecretary of state from early 1949 to early 1952.[149][self-published source?] Astrophysicist Hakeem Oluseyi argued that accusations against Webb were based on a quote falsely attributed to him on Wikipedia and could find little to no evidence that he took part in anti-gay discrimination.[150][149]

In March 2021, four scientists published an opinion piece in Scientific American urging NASA to reconsider the name of the telescope, based on Webb's alleged complicity.[150] The controversy was widely reported by the press.[151][152][153] In September 2021, NASA announced its decision not to rename the telescope.[154] O'Keefe, who made the decision to name the telescope after Webb, stated that to suggest Webb should "be held accountable for that activity when there's no evidence to even hint [that he participated in it] is an injustice".[84][149][self-published source?][155] The American Astronomical Society sent NASA administrator Bill Nelson two letters requesting NASA release a public report detailing their investigation.[156][157] The inquiry is ongoing; documents from a 1969 appeals ruling (regarding the 1963 firing of an employee) suggest that firing gay people was considered customary within the agency.[158][159]

Mission goals

The James Webb Space Telescope has four key goals:

These goals can be accomplished more effectively by observation in near-infrared light rather than light in the visible part of the spectrum. For this reason, JWST's instruments will not measure visible or ultraviolet light like the Hubble Telescope, but will have a much greater capacity to perform infrared astronomy. JWST will be sensitive to a range of wavelengths from 0.6 to 28 μm (corresponding respectively to orange light and deep infrared radiation at about 100 K or −173 °C).

JWST may be used to gather information on the dimming light of star KIC 8462852, which was discovered in 2015, and has some abnormal light-curve properties.[161]

Additionally, it will be able to tell if an exoplanet has methane in its atmosphere, allowing astronomers to determine whether or not the methane is a biosignature.[162][163]

Orbit design

JWST is not exactly at the L2 point, but circles around it in a halo orbit.
Alternative Hubble Space Telescope views of the Carina Nebula, comparing ultraviolet and visible (top) and infrared (bottom) astronomy. Far more stars are visible in the latter.

JWST orbits the Sun near the second Lagrange point (L2) of the Sun–Earth system, which is 1,500,000 km (930,000 mi) farther from the Sun than the Earth's orbit, and about four times farther than the Moon's orbit. Normally an object circling the Sun farther out than Earth would take longer than one year to complete its orbit. But near the L2 point, the combined gravitational pull of the Earth and the Sun allow a spacecraft to orbit the Sun in the same time that it takes the Earth. Staying close to Earth allows data rates to be much faster for a given size of antenna.

The telescope circles about the Sun–Earth L2 point in a halo orbit, which is inclined with respect to the ecliptic, has a radius varying between about 250,000 km (160,000 mi) and 832,000 km (517,000 mi), and takes about half a year to complete.[23] Since L2 is just an equilibrium point with no gravitational pull, a halo orbit is not an orbit in the usual sense: the spacecraft is actually in orbit around the Sun, and the halo orbit can be thought of as controlled drifting to remain in the vicinity of the L2 point.[164] This requires some station-keeping: around 2.5 m/s per year[165] from the total v budget of 93 m/s.[166] Two sets of thrusters constitute the observatory's propulsion system.[167] Because the thrusters are located solely on the Sun-facing side of the observatory, all station-keeping operations are designed to slightly undershoot the required amount of thrust in order to avoid pushing the JWST beyond the semi-stable L2 point, a situation which would be unrecoverable. Randy Kimble, the Integration and Test Project Scientist for the James Webb Space Telescope, compared the precise station-keeping of the JWST to "Sisyphus [...] rolling this rock up the gentle slope near the top of the hill – we never want it to roll over the crest and get away from him".[168]

Animation of James Webb Space Telescope trajectory
Top view
Side view
Side view from the Sun

Infrared astronomy

Infrared observations can see objects hidden in visible light, such as the HUDF-JD2 shown here.
Atmospheric windows in the infrared: Much of this type of light is blocked when viewed from the Earth's surface. It would be like looking at a rainbow but only seeing one color.

JWST is the formal successor to the Hubble Space Telescope (HST), and since its primary emphasis is on infrared astronomy, it is also a successor to the Spitzer Space Telescope. JWST will far surpass both those telescopes, being able to see many more and much older stars and galaxies.[169] Observing in the infrared spectrum is a key technique for achieving this, because of cosmological redshift, and because it better penetrates obscuring dust and gas. This allows observation of dimmer, cooler objects. Since water vapor and carbon dioxide in the Earth's atmosphere strongly absorbs most infrared, ground-based infrared astronomy is limited to narrow wavelength ranges where the atmosphere absorbs less strongly. Additionally, the atmosphere itself radiates in the infrared spectrum, often overwhelming light from the object being observed. This makes a space telescope preferable for infrared observation.[170]

The more distant an object is, the younger it appears; its light has taken longer to reach human observers. Because the universe is expanding, as the light travels it becomes red-shifted, and objects at extreme distances are therefore easier to see if viewed in the infrared.[171] JWST's infrared capabilities are expected to let it see back in time to the first galaxies forming just a few hundred million years after the Big Bang.[172]

Infrared radiation can pass more freely through regions of cosmic dust that scatter visible light. Observations in infrared allow the study of objects and regions of space which would be obscured by gas and dust in the visible spectrum,[171] such as the molecular clouds where stars are born, the circumstellar disks that give rise to planets, and the cores of active galaxies.[171]

Relatively cool objects (temperatures less than several thousand degrees) emit their radiation primarily in the infrared, as described by Planck's law. As a result, most objects that are cooler than stars are better studied in the infrared.[171] This includes the clouds of the interstellar medium, brown dwarfs, planets both in our own and other solar systems, comets, and Kuiper belt objects that will be observed with the Mid-Infrared Instrument (MIRI).[42][172]

Some of the missions in infrared astronomy that impacted JWST development were Spitzer and the Wilkinson Microwave Anisotropy Probe (WMAP).[173] Spitzer showed the importance of mid-infrared, which is helpful for tasks such as observing dust disks around stars.[173] Also, the WMAP probe showed the universe was "lit up" at redshift 17, further underscoring the importance of the mid-infrared.[173] Both these missions were launched in the early 2000s, in time to influence JWST development.[173]

Ground support and operations

The Space Telescope Science Institute (STScI), in Baltimore, Maryland, on the Homewood Campus of Johns Hopkins University, was selected as the Science and Operations Center (S&OC) for JWST with an initial budget of US$162.2 million intended to support operations through the first year after launch.[174] In this capacity, STScI will be responsible for the scientific operation of the telescope and delivery of data products to the astronomical community. Data will be transmitted from JWST to the ground via the NASA Deep Space Network, processed and calibrated at STScI, and then distributed online to astronomers worldwide. Similar to how Hubble is operated, anyone, anywhere in the world, will be allowed to submit proposals for observations. Each year several committees of astronomers will peer review the submitted proposals to select the projects to observe in the coming year. The authors of the chosen proposals will typically have one year of private access to the new observations, after which the data will become publicly available for download by anyone from the online archive at STScI.

The bandwidth and digital throughput of the satellite is designed to operate at 458 gigabits of data per day for the length of the mission (equivalent to a sustained rate of 5.42 Mbps).[33] Most of the data processing on the telescope is done by conventional single-board computers.[175] The digitization of the analog data from the instruments is performed by the custom SIDECAR ASIC (System for Image Digitization, Enhancement, Control And Retrieval Application Specific Integrated Circuit). NASA stated that the SIDECAR ASIC will include all the functions of a 9.1 kg (20 lb) instrument box in a 3 cm (1.2 in) package and consume only 11 milliwatts of power.[176] Since this conversion must be done close to the detectors, on the cold side of the telescope, the low power dissipation is crucial for maintaining the low temperature required for optimal operation of JWST.[176]

Micrometeoroid strike

The C3[c] mirror segment suffered a micrometeoroid strike from a large dust mote-sized particle between 23 and 25 May, the fifth and largest strike since launch, reported 8 June 2022, which required engineers to compensate for the strike using a mirror actuator.[178] Despite the strike, a NASA characterization report states "all JWST observing modes have been reviewed and confirmed to be ready for science use" as of July 10, 2022.[179]

From launch through commissioning

Launch

The launch (designated Ariane flight VA256) took place as scheduled at 12:20 UTC on 25 December 2021 on an Ariane 5 rocket that lifted off from the Guiana Space Centre in French Guiana.[180][181] The telescope was confirmed to be receiving power, starting a two-week deployment phase of its parts[182] and traveling to its target destination.[183][184][185] The telescope was released from the upper stage 27 minutes 7 seconds after launch, beginning a 30-day adjustment to place the telescope in a Lissajous orbit[186] around the L2 Lagrange point.

The telescope was launched with slightly less speed than needed to reach its final orbit, and slowed down as it travelled away from Earth, in order to reach L2 with only the velocity needed to enter its orbit there. The telescope reached L2 on 24 January 2022. The flight included three planned course corrections to adjust its speed and direction. This is because the observatory could recover from underthrust (going too slowly), but could not recover from overthrust (going too fast) – to protect highly temperature-sensitive instruments, the sunshield must remain between telescope and Sun, so the spacecraft could not turn around or use its thrusters to slow down.[187]

Transit and structural deployment

Structural deployment timeline[44]

JWST was released from the rocket upper stage 27 minutes after a flawless launch.[180][189] Starting 31 minutes after launch, and continuing for about 13 days, JWST began the process of deploying its solar array, antenna, sunshield, and mirrors.[190] Nearly all deployment actions are commanded by the Space Telescope Science Institute in Baltimore, except for two early automatic steps, solar panel unfolding and communication antenna deployment.[191][192] The mission was designed to give ground controllers flexibility to change or modify the deployment sequence in case of problems.[193]

Structural deployment sequence

At 7:50 p.m. EST on 25 December 2021, about 12 hours after launch, the telescope's pair of primary rockets began firing for 65 minutes to make the first of three planned mid-course corrections.[194] On day two, the high gain communication antenna deployed automatically.[193]

On 27 December 2021, at 60 hours after launch, Webb's rockets fired for nine minutes and 27 seconds to make the second of three mid-course corrections for the telescope to arrive at its L2 destination.[195] On 28 December 2021, three days after launch, mission controllers began the multi-day deployment of Webb's all-important sunshield. On 30 December 2021, controllers successfully completed two more steps in unpacking the observatory. First, commands deployed the aft "momentum flap", a device that provides balance against solar pressure on the sunshield, saving fuel by reducing the need for thruster firing to maintain Webb's orientation.[196]

On 31 December 2021, the ground team extended the two telescoping "mid booms" from the left and right sides of the observatory.[197] The left side deployed in 3 hours and 19 minutes; the right side took 3 hours and 42 minutes.[198][197] Commands to separate and tension the membranes followed between 3 and 4th January and were successful.[197] On 5 January 2022, mission control successfully deployed the telescope's secondary mirror, which locked itself into place to a tolerance of about one and a half millimeters.[199]

The last step of structural deployment was to unfold the wings of the primary mirror. Each panel consists of three primary mirror segments and had to be folded to allow the space telescope to be installed in the fairing of the Ariane rocket for the launch of the telescope. On 7 January 2022, NASA deployed and locked in place the port-side wing,[200] and on 8 January, the starboard-side mirror wing. This successfully completed the structural deployment of the observatory.[201][202][203]

On 24 January 2022, at 2:00 p.m. EST,[204] nearly a month after launch, a third and final course correction took place, inserting JWST into its planned halo orbit around the Sun–Earth L2 point.[205][206]

Animation of JWST's halo orbit

Commissioning and testing

On 12 January 2022, while still in transit, mirror alignment began. The primary mirror segments and secondary mirror were moved away from their protective launch positions. This took about 10 days, because the 132[207] actuator motors are designed to fine-tune the mirror positions at microscopic accuracy (10 nanometer increments) and must each move over 1.2 million increments (12.5 mm) during initial alignment.[208][34]

Mirror alignment requires each of the 18 mirror segments, and the secondary mirror, to be positioned to within 50 nanometers. NASA compares the required accuracy by analogy: "If the Webb primary mirror were the size of the United States, each [mirror] segment would be the size of Texas, and the team would need to line the height of those Texas-sized segments up with each other to an accuracy of about 1.5 inches".[209]

Mirror alignment is a complex operation split into seven phases, that has been repeatedly rehearsed using a 1:6 scale model of the telescope.[209] Once the mirrors reach 120 K (−153 °C; −244 °F),[210] NIRCam targets a bright star, the 6th magnitude star HD 84406 in Ursa Major.[d][212][213] To do this, NIRCam takes 1560 images of the sky and uses these wide-ranging images to determine where in the sky each segment of the main mirror is initially pointing.[214] Initially, the individual primary mirror segments were greatly misaligned, so the image contained 18 separate, blurry, images of the star field, each containing an image of the target star. The 18 images of HD 84406 are matched to their respective mirror segments, and the 18 segments are brought into approximate alignment centered on the star ("Segment Image Identification"). Each segment is then individually corrected of its major focusing errors, using a technique called phase retrieval, resulting in 18 separate good quality images from the 18 mirror segments ("Segment Alignment"). The 18 images from each segment, are then moved so they precisely overlap to create a single image ("Image Stacking").[209]

With the mirrors now positioned for almost correct images, they must be fine tuned to their operational accuracy of 50 nanometers, less than one wavelength of the light that will be detected. A technique called dispersed fringe sensing compares images from 20 pairings of mirrors, allowing most of the errors to be corrected ("Coarse Phasing"), and then introduces light defocus to each segment's image, allowing detection and correction of almost all remaining errors ("Fine Phasing"). These two processes are repeated three times, and Fine Phasing will be routinely checked throughout the telescope's operation. After three rounds of Coarse and Fine Phasing, the telescope will be well aligned at one place in the NIRCam field of view. Measurements will be made at various points in the captured image, across all instruments, and corrections calculated from the detected variations in intensity, giving a well-aligned outcome across all instruments ("Telescope Alignment Over Instrument Fields of View"). Finally, a last round of Fine Phasing and checks of image quality on all instruments is performed, to ensure that any small residual errors remaining from the previous steps, are corrected ("Iterate Alignment for Final Correction"). The telescope's mirror segments are then aligned and able to capture precise focused images.[209]

In preparation for alignment, NASA announced at 19:28 UTC on 3 February 2022, that NIRCam had detected the telescope's first photons (although not yet complete images).[209][215] On 11 February 2022, NASA announced the telescope had almost completed phase 1 of alignment, with every segment of its primary mirror having located and imaged the target star HD 84406, and all segments brought into approximate alignment.[214] Phase 1 alignment was completed on 18 February 2022,[216] and a week later, phases 2 and 3 were also completed on 25 February 2022.[217] This means the 18 segments are working in unison, however until all 7 phases are complete, the segments still act as 18 smaller telescopes rather than one larger one.[217] At the same time as the primary mirror is being commissioned, hundreds of other instrument commissioning and calibration tasks are also ongoing.[218]

Allocation of observation time

JWST observing time is allocated through a General Observers (GO) program, a Guaranteed Time Observations (GTO) program, and a Director's Discretionary Early Release Science (DD-ERS) program.[222] The GTO program provides guaranteed observing time for scientists who developed hardware and software components for the observatory. The GO program provides all astronomers the opportunity to apply for observing time and will represent the bulk of the observing time. GO programs are selected through peer review by a Time Allocation Committee (TAC), similar to the proposal review process used for the Hubble Space Telescope.

Early Release Science program

In November 2017, the Space Telescope Science Institute announced the selection of 13 Director's Discretionary Early Release Science (DD-ERS) programs, chosen through a competitive proposal process.[223][224] The observations for these programs will be obtained during the first five months of JWST science operations after the end of the commissioning period. A total of 460 hours of observing time was awarded to these 13 programs, which span science topics including the Solar System, exoplanets, stars and star formation, nearby and distant galaxies, gravitational lenses, and quasars. These 13 ERS programs will use a total of 242.8 hours of observing time on the telescope (not including JWST observing overheads and slew time).

Early Release Science programs
Name Principal Investigator Category Observation time (hours)
Radiative Feedback from Massive Stars as Traced by Multiband Imaging and Spectroscopic Mosaics Olivier Berné Stellar Physics 8.3[225]
IceAge: Chemical Evolution of Ices during Star Formation Melissa McClure Stellar Physics 13.4[226]
Through the Looking GLASS: A JWST Exploration of Galaxy Formation and Evolution from Cosmic Dawn to Present Day Tommaso Treu Galaxies and the IGM 24.3[227]
A JWST Study of the Starburst-AGN Connection in Merging LIRGs Lee Armus Galaxies and the IGM 8.7[228]
The Resolved Stellar Populations Early Release Science Program Daniel Weisz Stellar Populations 20.3[229]
Q-3D: Imaging Spectroscopy of Quasar Hosts with JWST Analyzed with a Powerful New PSF Decomposition and Spectral Analysis Package Dominika Wylezalek Massive Black Holes and their Galaxies 17.4[230]
The Cosmic Evolution Early Release Science (CEERS) Survey Steven Finkelstein Galaxies and the IGM 36.6[231]
Establishing Extreme Dynamic Range with JWST: Decoding Smoke Signals in the Glare of a Wolf-Rayet Binary Ryan Lau Stellar Physics 6.5[232]
TEMPLATES: Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation Jane Rigby Galaxies and the IGM 26.0[233]
Nuclear Dynamics of a Nearby Seyfert with NIRSpec Integral Field Spectroscopy Misty Bentz Massive Black Holes and their Galaxies 1.5[234]
The Transiting Exoplanet Community Early Release Science Program Natalie Batalha Planets and Planet Formation 52.1[235]
ERS observations of the Jovian System as a Demonstration of JWST's Capabilities for Solar System Science Imke de Pater Solar System 9.3[236]
High Contrast Imaging of Exoplanets and Exoplanetary Systems with JWST Sasha Hinkley Planets and Planet Formation 18.4[237]

General Observer Program

For GO Cycle 1 there were 6,000 hours of observation time available to allocate, and 1,173 proposals were submitted requesting a total of 24,500 hours of observation time.[238] Selection of Cycle 1 GO programs was announced on 30 March 2021, with 266 programs approved. These include 13 large programs and treasury programs producing data for public access.[239]

Scientific results

The release of the first full-color images and spectroscopic data was on 12 July 2022, which also marked the official beginning of Webb's general science operations; President Joe Biden revealed the first image, Webb's First Deep Field, on 11 July 2022.[242][243] NASA announced the list of observations targeted for release:[246][247][248]

  • Carina Nebula – young, star-forming region called NGC 3324 displaying "Cosmic Cliffs" about 8500 light-years from Earth.
  • WASP-96b – including an analysis of atmosphere with evidence of water around a giant gas planet orbiting a distant star 1120 light-years from Earth.
  • Southern Ring Nebula – clouds of gas and dust expelled by a dying star 2500 light-years from Earth.
  • Stephan's Quintet – a visual display of five galaxies with colliding gas and dust clouds creating new stars; four central galaxies are 290 million light-years from Earth.
  • SMACS J0723.3-7327 – a gravitationally lensed view called Webb's First Deep Field 4.6 billion light-years from Earth, with distant galaxies as far away as 13.1 billion light-years. Sometimes abbreviated as SMACS 0723.[247][249]

On 14 July 2022, NASA presented images of Jupiter and related areas captured, for the first time, and including infrared views, by the James Webb Space Telescope.[250]

A paper about the science performance from commissioning, released by NASA, ESA and CSA scientists, describes that "almost across the board, the science performance of JWST is better than expected". The paper describes a series of observations during the commissioning, when the instruments captured spectra of transiting exoplanets with a precision better than 1000 ppm per data point and tracked moving objects with speeds up to 67 milliarcseconds/second, more than twice as fast as the requirement.[a] It also obtained the spectra of hundreds of stars simultaneously in a dense field towards the Galactic Center. Other targets described in the paper:[21]

Within two weeks of the first Webb images, several preprint papers described a wide range of early galaxies believed to date from 235 million years (z=16.7) to 280 million years after the Big Bang, far earlier than previously known. The results await peer review.[252]

Gallery

See also

Notes

  1. ^ a b JWST was designed with the requirement to track objects that move as fast as Mars, which has a maximum apparent speed on the sky of 30 mas/s, which is the value given in the technical specification, i.e. the nominal value.[20]
    During commissioning, various asteroids were observed to determine the actual limitation for the speed of objects and it turned out to be 67 mas/s, which is more than twice the nominal value. Tracking at rates of 30–67 mas/s showed accuracies similar to tracking of slower targets. Thus, the telescope is able to observe also near-Earth asteroids (NEAs), comets closer to perihelion and interstellar objects.[21]: 8 
  2. ^ "Baffled", in this context, means enclosed in a tube in a similar manner to a conventional optical telescope, which helps to stop stray light entering the telescope from the side. For an actual example, see the following link: Freniere, E.R. (1981). "First-order design of optical baffles". Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, First-order design of optical baffles. Radiation Scattering in Optical Systems. Vol. 257. pp. 19–28. Bibcode:1981SPIE..257...19F. doi:10.1117/12.959598.
  3. ^ The C3 mirror segment is positioned in the outer ring of segments, located at the '5 o'clock' number of a clock face, when viewing the primary mirror face-on.[177]
  4. ^ HD 84406 is a star approximately 258.5 light-years away in the constellation of Ursa Major. The star is a spectral type G star and has a high proper motion.[211]
  5. ^ 2MASS J17554042+6551277, also known as UNSW-V 084 and TYC 4212-1079-1,[219] is a star in the constellation Draco, in the Milky Way. It is located almost 2,000 light years away from Earth, within a degree of the north ecliptic pole. Its visual apparent magnitude mv is 10.95, which makes it much too faint to be observed with the naked eye. It is cooler than the Sun, but some 13 to 16 times brighter in visible light,[220] and is consequently not a sun-like star. Its motion vector in the direction of the Sun is 51 km/s.[219]

References

  1. ^ a b "NASA JWST "Who are the partners in the Webb project?"". NASA. Archived from the original on 29 November 2011. Retrieved 18 November 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ^ Kelso, Thomas S. (25 December 2021). "JWST". Celestrak. Celestrak. Archived from the original on 18 January 2022. Retrieved 26 December 2021.
  3. ^ "FAQ Full General Public Webb Telescope/NASA". jwst.nasa.gov. Archived from the original on 23 July 2019. Retrieved 13 January 2022.
  4. ^ "NASA Says Webb's Excess Fuel Likely to Extend its Lifetime Expectations – James Webb Space Telescope". blogs.nasa.gov. Archived from the original on 6 January 2022. Retrieved 30 December 2021.
  5. ^ Clark, Stephen [@StephenClark1] (23 December 2021). "The exact launch mass of the James Webb Space Telescope: 6161.4 kilograms. That figure includes 167.5 kg of hydrazine and 132.5 kg of dinitrogen tetroxide for the propulsion system" (Tweet). Retrieved 23 December 2021 – via Twitter.
  6. ^ a b "JWST Orbit". JWST User Documentation. Space Telescope Science Institute. Archived from the original on 11 July 2022. Retrieved 25 December 2021.
  7. ^ "JWST Telescope". James Webb Space Telescope User Documentation. Space Telescope Science Institute. 23 December 2019. Archived from the original on 11 July 2022. Retrieved 11 June 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  8. ^ a b Achenbach, Joel (5 August 2022). "The Webb telescope is astonishing. But the universe is even more so - This new tool can't do everything, but it's capturing some of the first light emitted after the big bang, and that is already revealing wonders". The Washington Post. Retrieved 7 August 2022.
  9. ^ Fisher, Alise; Pinol, Natasha; Betz, Laura (11 July 2022). "President Biden Reveals First Image from NASA's Webb Telescope". NASA. Archived from the original on 12 July 2022. Retrieved 12 July 2022.
  10. ^ a b c "Comparison: Webb vs Hubble Telescope – Webb/NASA". www.jwst.nasa.gov. Archived from the original on 21 January 2022. Retrieved 12 July 2022.
  11. ^ Lallo, Matthew D. (2012). "Experience with the Hubble Space Telescope: 20 years of an archetype". Optical Engineering. 51 (1): 011011–011011–19. arXiv:1203.0002. Bibcode:2012OptEn..51a1011L. doi:10.1117/1.OE.51.1.011011. S2CID 15722152.
  12. ^ "Mirrors Webb/NASA". webb.nasa.gov. Archived from the original on 4 February 2022. Retrieved 12 July 2022.
  13. ^ a b "A Deeper Sky | by Brian Koberlein". briankoberlein.com. Archived from the original on 19 March 2022. Retrieved 5 January 2022.
  14. ^ a b c "FAQ for Scientists Webb Telescope/NASA". jwst.nasa.gov. Archived from the original on 5 January 2022. Retrieved 5 January 2022.
  15. ^ Shelton, Jim (3 March 2016). "Shattering the cosmic distance record, once again". Yale University. Archived from the original on 13 March 2016. Retrieved 4 March 2016.
  16. ^ "Hubble breaks cosmic distance record". SpaceTelescope.org. 3 March 2016. heic1604. Archived from the original on 8 March 2016. Retrieved 3 March 2016.
  17. ^ Oesch, P. A.; Brammer, G.; van Dokkum, P.; et al. (March 2016). "A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble Space Telescope Grism Spectroscopy". The Astrophysical Journal. 819 (2). 129. arXiv:1603.00461. Bibcode:2016ApJ...819..129O. doi:10.3847/0004-637X/819/2/129. S2CID 119262750.
  18. ^ Atkinson, Nancy. "Hubble Has Looked Back in Time as Far as It Can And Still Can't Find The First Stars". Universe Today. Archived from the original on 9 January 2022. Retrieved 9 January 2022 – via ScienceAlert.
  19. ^ a b "Infrared astronomy from earth orbit". Infrared Processing and Analysis Center, NASA Spitzer Science Center, California Institute of Technology. 2017. Archived from the original on 21 December 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  20. ^ Fisher, Alise (14 July 2022). "Webb Images of Jupiter and More Now Available in Commissioning Data". James Webb Space Telescope (NASA Blogs). Retrieved 8 August 2022.
  21. ^ a b c Rigby, Jane; Perrin, Marshall; McElwain, Michael; Kimble, Randy; Friedman, Scott; Lallo, Matt; Doyon, René; Feinberg, Lee; Ferruit, Pierre; Glasse, Alistair; Rieke, Marcia; et al. (12 July 2022). "Characterization of JWST science performance from commissioning". NASA-ESA-CSA Publication. arXiv:2207.05632. Archived from the original on 14 July 2022. Retrieved 13 July 2022.
  22. ^ "Technical FAQ Specifically On Solar System Observations". James Webb Space Telescope. NASA. Archived from the original on 12 July 2022. Retrieved 29 July 2022.
  23. ^ a b c "L2 Orbit". Space Telescope Science Institute. Archived from the original on 3 February 2014. Retrieved 28 August 2016.
  24. ^ a b c "The Sunshield". nasa.gov. NASA. Archived from the original on 10 August 2017. Retrieved 28 August 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  25. ^ Drake, Nadia (24 April 2015). "Hubble Still Wows At 25, But Wait Till You See What's Next". National Geographic. Archived from the original on 23 June 2019. Retrieved 24 April 2015.
  26. ^ "The James Webb Space Telescope". nasa.gov. Archived from the original on 30 June 2019. Retrieved 28 August 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  27. ^ "Sunshield Coatings Webb/NASA". jwst.nasa.gov. Archived from the original on 29 December 2021. Retrieved 3 May 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  28. ^ Clery, Daniel (27 March 2018). "NASA announces more delays for giant space telescope". Science. Archived from the original on 24 December 2021. Retrieved 5 June 2018.
  29. ^ Morring, Frank Jr. (16 December 2013). "JWST Sunshade Folding, Deployment In Test". Aviation Week & Space Technology. pp. 48–49. ISSN 0005-2175. Archived from the original on 19 March 2022. Retrieved 27 December 2021.
  30. ^ Fisher, Alise (30 December 2021). "Webb Ready for Sunshield Deployment and Cooldown". James Webb Space Telescope (NASA Blogs). Archived from the original on 30 December 2021. Retrieved 31 December 2021.
  31. ^ "JWST Wavefront Sensing and Control". Space Telescope Science Institute. Archived from the original on 5 August 2012. Retrieved 9 June 2011.
  32. ^ "Keck I and Keck II Telescopes". W. M. Keck Observatory. Archived from the original on 1 April 2022. Retrieved 12 July 2022.
  33. ^ a b Mallonee, Laura (22 October 2019). "NASA's Biggest Telescope Ever Prepares for a 2021 Launch". Wired. Archived from the original on 16 May 2022. Retrieved 4 June 2021.
  34. ^ a b "Mirror, Mirror…On Its Way! – James Webb Space Telescope". Blogs.nasa.gov. Archived from the original on 27 January 2022. Retrieved 12 February 2022.
  35. ^ "JWST Mirrors". Space Telescope Science Institute. Archived from the original on 5 August 2012. Retrieved 9 June 2011.
  36. ^ Amos, Jonathan (16 March 2022). "James Webb: 'Fully focused' telescope beats expectations". BBC News. Archived from the original on 11 July 2022. Retrieved 15 July 2022.
  37. ^ a b "JWST: Integrated Science Instrument Module (ISIM)". NASA. 2017. Archived from the original on 2 June 2019. Retrieved 2 February 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  38. ^ "James Webb Space Telescope Near Infrared Camera". STScI. Archived from the original on 21 March 2013. Retrieved 24 October 2013.
  39. ^ "NIRCam for the James Webb Space Telescope". University of Arizona. Archived from the original on 3 November 2021. Retrieved 24 October 2013.
  40. ^ a b c "JWST Current Status". STScI. Archived from the original on 15 July 2009. Retrieved 5 July 2008.
  41. ^ "NIRSpec – the near-infrared spectrograph on JWST". European Space Agency. 22 February 2015. Archived from the original on 3 April 2019. Retrieved 2 February 2017.
  42. ^ a b c "MIRI spectrometer for NGST". Archived from the original on 27 September 2011.
  43. ^ a b "JWST: Mid-Infrared Instrument (MIRI)". NASA. 2017. Archived from the original on 12 June 2019. Retrieved 3 February 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  44. ^ a b "JWST". NASA. Archived from the original on 26 June 2015. Retrieved 29 June 2015. Public Domain This article incorporates text from this source, which is in the public domain.
  45. ^ Banks, Kimberly; Larson, Melora; Aymergen, Cagatay; Zhang, Burt (2008). Angeli, George Z.; Cullum, Martin J. (eds.). "James Webb Space Telescope Mid-Infrared Instrument Cooler systems engineering" (PDF). Proceedings of SPIE. Modeling, Systems Engineering, and Project Management for Astronomy III. 7017: 5. Bibcode:2008SPIE.7017E..0AB. doi:10.1117/12.791925. S2CID 17507846. Archived (PDF) from the original on 6 October 2021. Retrieved 6 February 2016. Fig. 1. Cooler Architecture Overview
  46. ^ Doyon, René; Hutchings, John B.; Beaulieu, Mathilde; Albert, Loic; Lafrenière, David; Willott, Chris; Touahri, Driss; Rowlands, Neil; Maszkiewicz, Micheal; Fullerton, Alex W.; Volk, Kevin; Martel, André R.; Chayer, Pierre; Sivaramakrishnan, Anand; Abraham, Roberto; Ferrarese, Laura; Jayawardhana, Ray; Johnstone, Doug; Meyer, Michael; Pipher, Judith L.; Sawicki, Marcin (22 August 2012). Clampin, Mark C; Fazio, Giovanni G; MacEwen, Howard A; Oschmann, Jacobus M (eds.). "The JWST Fine Guidance Sensor (FGS) and Near-Infrared Imager and Slitless Spectrograph (NIRISS)". Proceedings of SPIE. Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave. 8442: 84422R. Bibcode:2012SPIE.8442E..2RD. doi:10.1117/12.926578. S2CID 120702854. "FGS features two modules: an infrared camera dedicated to fine guiding of the observatory and a science camera module, the Near-Infrared Imager and Slitless Spectrograph (NIRISS)"
  47. ^ "The Spacecraft Bus". NASA James Webb Space Telescope. 2017. Archived from the original on 6 July 2019. Retrieved 26 November 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  48. ^ a b "The JWST Observatory". NASA. 2017. Archived from the original on 20 May 2019. Retrieved 28 December 2016. The Observatory is the space-based portion of the James Webb Space Telescope system and is comprisedof three elements: the Integrated Science Instrument Module (ISIM), the Optical Telescope Element (OTE), which includes the mirrors and backplane, and the Spacecraft Element, which includes the spacecraft bus and the sunshield Public Domain This article incorporates text from this source, which is in the public domain.
  49. ^ "Integrated Science Instrument Module (ISIM)". NASA James Webb Space Telescope. 2017. Archived from the original on 3 December 2016. Retrieved 30 November 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  50. ^ "PRIME: The Untold Story Of NASA's James Webb Space Telescope". www.satmagazine.com. February 2012. Retrieved 6 April 2021.
  51. ^ Sloan, Jeff (12 October 2015). "James Webb Space Telescope spacecraft inches towards full assembly". Composites World. Archived from the original on 24 October 2019. Retrieved 28 December 2016.
  52. ^ "JWST Propulsion". JWST User Documentation. Space Telescope Science Institute. Archived from the original on 11 July 2022. Retrieved 29 December 2021.
  53. ^ Clark, Stephen (28 November 2021). "NASA gives green light to fuel James Webb Space Telescope". Spaceflight Now. Archived from the original on 25 June 2022. Retrieved 2 December 2021.
  54. ^ "Why is Webb not serviceable like Hubble?". James Webb Space Telescope (FAQ). Archived from the original on 3 July 2022. Retrieved 31 December 2021.
  55. ^ a b "Relief as NASA's most powerful space telescope finishes risky unfolding". Science. 8 January 2022. Archived from the original on 31 January 2022. Retrieved 11 January 2022.
  56. ^ Smith, Marcia (30 August 2018). "Zurbuchen Taking One Last Look at JWST Servicing Compatiblity". SpacePolicyOnline. Archived from the original on 31 December 2021. Retrieved 31 December 2021.
  57. ^ Foust, Jeff (2 February 2018). "Scientists, engineers push for servicing and assembly of future space observatories". SpaceNews. Archived from the original on 15 July 2022. Retrieved 31 December 2021.
  58. ^ Grush, Loren (28 December 2021). "NASA's James Webb Space Telescope is about to transform into its final form". The Verge. Archived from the original on 9 July 2022. Retrieved 11 January 2022.
  59. ^ a b McCarthy SG, Autio GW (1978). Infrared Detector Performance In The Shuttle Infrared Telescope Facility (SIRTF). 1978 Los Angeles Technical Symposium. Utilization of Infrared Detectors. Vol. 81. Society of Photographic Instrumentation Engineers. pp. 81–88. Bibcode:1978SPIE..132...81M. doi:10.1117/12.956060. Archived from the original on 5 March 2017. Retrieved 8 December 2016.
  60. ^ "How cold can you go? Cooler tested for NASA telescope". Phys.org. 14 June 2016. Archived from the original on 11 July 2022. Retrieved 31 January 2017.
  61. ^ "JPL: Herschel Space Observatory: Related Missions". NASA, Jet Propulsion Laboratory, Goddard Flight Center, California Institute of Technology. Archived from the original on 3 December 2016. Retrieved 4 June 2012. Public Domain This article incorporates text from this source, which is in the public domain.
  62. ^ "What is ISO?". ESA. 2016. Archived from the original on 10 November 2021. Retrieved 4 June 2021.
  63. ^ "Hubble Space Telescope – Wide Field Camera 3". NASA. 22 August 2016. Archived from the original on 13 November 2021. Retrieved 9 December 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  64. ^ a b c d e f Reichhardt, Tony (March 2006). "US astronomy: Is the next big thing too big?". Nature. 440 (7081): 140–143. Bibcode:2006Natur.440..140R. doi:10.1038/440140a. PMID 16525437.
  65. ^ "Nexus Space Telescope". MIT. Archived from the original on 29 August 2011. Retrieved 23 August 2011.
  66. ^ Dwayne Brown/Michael Braukus (18 Jun 2007) NASA and ESA Sign Agreements for Future Cooperation Archived 19 March 2022 at the Wayback Machine RELEASE : 07-139
  67. ^ a b Haviv Rettig Gur (5 January 2022). "Space is changing. Webb is just the start, says ex-Israeli who was in from its dawn". The Times of Israel. Archived from the original on 19 March 2022. Retrieved 7 January 2022.
  68. ^ "Advanced Concepts Studies – The 4 m Aperture "Hi-Z" Telescope". NASA Space Optics Manufacturing Technology Center. Archived from the original on 15 October 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  69. ^ a b "STSCI JWST History 1994". Archived from the original on 3 February 2014. Retrieved 29 December 2018.
  70. ^ "Astrononmy and Astrophysics in the New Millennium". NASA. Archived from the original on 25 December 2021. Retrieved 27 July 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  71. ^ de Weck, Olivier L.; Miller, David W.; Mosier, Gary E. (2002). "Multidisciplinary analysis of the NEXUS precursor space telescope" (PDF). In MacEwen, Howard A. (ed.). Highly Innovative Space Telescope Concepts. Highly Innovative Space Telescope Concepts. Vol. 4849. p. 294. Bibcode:2002SPIE.4849..294D. CiteSeerX 10.1.1.664.8727. doi:10.1117/12.460079. S2CID 18725988. Archived (PDF) from the original on 23 September 2017. Retrieved 27 July 2011.
  72. ^ Brown, R. A. (1996). "1996swhs.conf..603B Page 603". Science with the Hubble Space Telescope – Ii: 603. Bibcode:1996swhs.conf..603B. Archived from the original on 14 January 2022. Retrieved 14 January 2022.
  73. ^ Thronson, H. A.; Hawarden, T.; Davies, J. K.; Lee, T. J.; Mountain, C. M.; Longair, M. (January 1991). "The Edison infrared space observatory and the universe at high redshifts". Advances in Space Research. 11 (2): 341–344. Bibcode:1991AdSpR..11b.341T. doi:10.1016/0273-1177(91)90514-k. ISSN 0273-1177. Archived from the original on 15 July 2022. Retrieved 15 December 2021.
  74. ^ Thronson, Harley, A., Jr.; Hawarden, Timothy G.; Bradshaw, Tom W.; Orlowska, Anna H.; Penny, Alan J.; Turner, R. F.; Rapp, Donald (1 November 1993). Bely, Pierre Y; Breckinridge, James B (eds.). "Edison radiatively cooled infrared space observatory". SPIE Proceedings. Space Astronomical Telescopes and Instruments II. SPIE. 1945: 92–99. doi:10.1117/12.158751. S2CID 120232788. Archived from the original on 15 July 2022. Retrieved 15 December 2021.
  75. ^ Dressler, A., ed. (1996). "Exploration and the Search for Origins: A Vision for Ultraviolet-Optical-Infrared Space Astronomy Report of the 'HST & Beyond' Committee" (PDF). Stsci.edu. Association of Universities for Research in Astronomy. Archived (PDF) from the original on 15 July 2022. Retrieved 12 February 2022.
  76. ^ Stockman, H. S. (June 1997). "The Next Generation Space Telescope. Visiting a time when galaxies were young". Space Telescope Science Institute, Baltimore, Maryland. The Association of Universities for Research in Astronomy, Washington, D.C.
  77. ^ Astronomy and Astrophysics Survey Committee; Board on Physics and Astronomy; Space Studies Board; Commission on Physical Sciences, Mathematics, and Applications; National Research Council (16 January 2001). Astronomy and Astrophysics in the New Millennium. Washington, D.C.: National Academies Press. doi:10.17226/9839. ISBN 978-0-309-07031-7. Archived from the original on 15 July 2022. Retrieved 15 December 2021.
  78. ^ "STSCI JWST History 1996". Stsci.edu. Archived from the original on 12 December 2012. Retrieved 16 January 2012.
  79. ^ "Goddard Space Flight Center design" Archived 6 January 2016 at the Wayback Machine. spacetelescope.org. Retrieved on 13 January 2014
  80. ^ "ESA Science & Technology: Ball Aerospace design for JWST". Archived 12 December 2012 at archive.today. Sci.esa.int. Retrieved 21 August 2013
  81. ^ "ESA Science & Technology: TRW design for JWST". Archived 12 December 2012 at archive.today. Sci.esa.int. Retrieved 21 August 2013
  82. ^ "ESA Science & Technology: Lockheed-Martin design for JWST". Archived 13 December 2012 at archive.today. Sci.esa.int. Retrieved 21 August 2013
  83. ^ a b "HubbleSite – Webb: Past and Future". Archived from the original on 10 December 2012. Retrieved 13 January 2012.
  84. ^ a b c Greenfieldboyce, Nell (30 September 2021). "Shadowed by controversy, NASA won't rename its new space telescope". NPR. Archived from the original on 30 September 2021. Retrieved 27 October 2021.
  85. ^ a b "About James Webb". NASA. Archived from the original on 27 March 2018. Retrieved 15 March 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  86. ^ "TRW Selected as JWST Prime Contractor". STCI. 11 September 2003. Archived from the original on 5 August 2012. Retrieved 13 January 2012.
  87. ^ "Northrop Grumman Completes Fabrication Of Sunshield Deployment Flight Structure For JWST". Space Daily. 13 December 2011. Archived from the original on 18 January 2022. Retrieved 10 December 2014.
  88. ^ a b John Mather. "James Webb Space Telescope (JWST)" (PDF). National Academy of Science. Archived from the original (PDF) on 10 November 2008. Retrieved 5 July 2008. Public Domain This article incorporates text from this source, which is in the public domain.
  89. ^ a b "European agreement on James Webb Space Telescope's Mid-Infrared Instrument (MIRI) signed" (Press release). ESA Media Relations Service. 9 June 2004. Archived from the original on 18 May 2009. Retrieved 6 May 2009.
  90. ^ "Canada's contribution to NASA's James Webb Space Telescope". canada.ca. Canadian Space Agency. 4 June 2007. Archived from the original on 18 January 2022. Retrieved 3 July 2021.
  91. ^ "Canadian Space Agency Delivers Canada's Contributions to the James Webb Space Telescope". SpaceQ. 30 July 2012. Archived from the original on 18 January 2022. Retrieved 3 July 2021.
  92. ^ "JWST Passes TNAR". STScI. Archived from the original on 5 August 2012. Retrieved 5 July 2008.
  93. ^ Berger, Brian (23 May 2007). "NASA Adds Docking Capability For Next Space Observatory". SPACE.com. Archived from the original on 30 June 2008. Retrieved 5 July 2008.
  94. ^ "James Webb Space Telescope sunshield is ready to fabricate". www.laserfocusworld.com. Archived from the original on 30 December 2021. Retrieved 30 December 2021.
  95. ^ "NASA's Webb Telescope Passes Key Mission Design Review Milestone". NASA. Archived from the original on 1 May 2010. Retrieved 2 May 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  96. ^ Clark, Stephen (12 August 2010). "NASA says JWST cost crunch impeding new missions". Spaceflight Now. Archived from the original on 29 April 2021. Retrieved 13 August 2010.
  97. ^ Berardelli, Phil (27 October 1997). "Next Generation Space Telescope will peer back to the beginning of time and space". CBS. Archived from the original on 19 October 2015. Retrieved 23 August 2011.
  98. ^ "NASA's James Webb Space Telescope Primary Mirror Fully Assembled". nasa.gov. 3 February 2016. Archived from the original on 4 February 2016. Retrieved 4 February 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  99. ^ "NASA's James Webb Space Telescope Secondary Mirror Installed". NASA. 7 March 2016. Archived from the original on 17 March 2016. Retrieved 23 March 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  100. ^ Yuhas, Alan (4 November 2016). "Nasa begins testing enormous space telescope made of gold mirrors". The Guardian. Archived from the original on 5 November 2016. Retrieved 5 November 2016.
  101. ^ "NASA Completes Webb Telescope Review, Commits to Launch in Early 2021". NASA. 27 June 2018. Archived from the original on 14 March 2020. Retrieved 27 June 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  102. ^ Achenbach, Joel (26 July 2018). "Northrop Grumman CEO is grilled about James Webb Space Telescope errors". The Washington Post. Archived from the original on 28 December 2019. Retrieved 28 December 2019.
  103. ^ "The two halves of Hubble's US$10 billion successor have finally come together after 12 years of waiting". Business Insider. Archived from the original on 15 July 2022. Retrieved 29 August 2019.
  104. ^ Clark, Stephen (30 September 2021). "After two decades, the Webb telescope is finished and on the way to its launch site". Spaceflight Now. Archived from the original on 6 October 2021. Retrieved 6 October 2021.
  105. ^ Wall, Mike (12 October 2021). "NASA's James Webb Space Telescope arrives in French Guiana ahead of December 18 launch". Space.com. Archived from the original on 12 October 2021. Retrieved 13 October 2021.
  106. ^ "FY 2022 NASA Congressional Budget Justification" (PDF). NASA. p. JWST-2. Archived (PDF) from the original on 10 June 2021. Retrieved 21 October 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  107. ^ Foust, Jeff (2 June 2021). "JWST launch slips to November". SpaceNews. Archived from the original on 15 July 2022. Retrieved 21 October 2021.
  108. ^ Lilly, Simon (27 November 1998). "The Next Generation Space Telescope (NGST)". University of Toronto. Archived from the original on 25 December 2021. Retrieved 23 August 2011.
  109. ^ "NGST Weekly Missive". 25 April 2002. Archived from the original on 15 July 2022. Retrieved 23 August 2011.
  110. ^ "NASA Modifies James Webb Space Telescope Contract". 12 November 2003. Archived from the original on 25 December 2021. Retrieved 23 August 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  111. ^ "Problems for JWST". 21 May 2005. Archived from the original on 25 December 2021. Retrieved 25 August 2011.
  112. ^ "Refocusing NASA's vision". Nature. 440 (7081): 127. 9 March 2006. Bibcode:2006Natur.440..127.. doi:10.1038/440127a. PMID 16525425.
  113. ^ Cowen, Ron (25 August 2011). "Webb Telescope Delayed, Costs Rise to $8 Billion". ScienceInsider. Archived from the original on 14 January 2012.
  114. ^ a b "Independent Comprehensive Review Panel, Final Report" (PDF). 29 October 2010. Archived (PDF) from the original on 17 November 2021. Retrieved 10 June 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  115. ^ Amos, Jonathan (22 August 2011). "JWST price tag now put at over $8 bn". BBC. Archived from the original on 25 December 2021. Retrieved 22 June 2018.
  116. ^ "NASA's James Webb Space Telescope to be Launched Spring 2019". NASA. 28 September 2017. Archived from the original on 7 February 2018. Retrieved 28 September 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  117. ^ a b "NASA Delays Launch of James Webb Space Telescope to 2020". Space.com. Archived from the original on 28 April 2022. Retrieved 27 March 2018.
  118. ^ "NASA Completes Webb Telescope Review, Commits to Launch in Early 2021". nasa.gov. NASA. 27 June 2018. Archived from the original on 14 March 2020. Retrieved 28 June 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  119. ^ "NASA delays launch of Webb telescope to no earlier than Dec. 24". 14 December 2021. Archived from the original on 15 December 2021. Retrieved 14 December 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  120. ^ 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–". Retrieved 16 April 2022.
  121. ^ a b c McKie, Robin (9 July 2011). "Nasa fights to save the James Webb space telescope from the axe". The Guardian. London. Archived from the original on 17 March 2017. Retrieved 14 December 2016.
  122. ^ "Appropriations Committee Releases the Fiscal Year 2012 Commerce, Justice, Science Appropriations". US House of representatives Committee on Appropriations. 6 July 2011. Archived from the original on 23 March 2012. Retrieved 7 July 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  123. ^ "US lawmakers vote to kill Hubble successor". SpaceDaily. 7 July 2011. Archived from the original on 10 July 2011. Retrieved 8 July 2011.
  124. ^ "Proposed NASA Budget Bill Would Cancel Major Space Telescope". Space.com. 6 July 2011. Archived from the original on 9 July 2011. Retrieved 11 July 2011.
  125. ^ Bergin, Chris (7 January 2015). "James Webb Space Telescope hardware entering key test phase". NASASpaceFlight.com. Archived from the original on 7 November 2017. Retrieved 28 August 2016.
  126. ^ Hand, E. (7 July 2011). "AAS Issues Statement on Proposed Cancellation of James Webb Space Telescope". American Astronomical Society. Archived from the original on 19 March 2018. Retrieved 1 February 2017.
  127. ^ "Mikulski Statement on House Appropriations Subcommittee Termination of James Webb Telescope". SpaceRef. 11 July 2011. Archived from the original on 15 July 2022. Retrieved 1 February 2017.
  128. ^ "Way Above the Shuttle Flight". The New York Times. 9 July 2011. Archived from the original on 19 March 2018. Retrieved 27 February 2017.
  129. ^ Harrold, Max (7 July 2011). "Bad news for Canada: U.S. could scrap new space telescope". The Vancouver Sun. Archived from the original on 31 July 2018. Retrieved 27 January 2019.
  130. ^ "NASA budget plan saves telescope, cuts space taxis". Reuters. 16 November 2011. Archived from the original on 24 September 2015. Retrieved 1 July 2017.
  131. ^ Leone, Dan (7 November 2012). "NASA Acknowledges James Webb Telescope Costs Will Delay Other Science Missions". SpaceNews. Archived from the original on 22 January 2013. Retrieved 12 January 2013.
  132. ^ a b Moskowitz, Clara (30 March 2015). "NASA Assures Skeptical Congress That the James Webb Telescope Is on Track". Scientific American. Archived from the original on 2 February 2017. Retrieved 29 January 2017.
  133. ^ Billings, Lee (27 October 2010). "The telescope that ate astronomy". Nature. 467 (7319): 1028–1030. doi:10.1038/4671028a. PMID 20981068.
  134. ^ Koren, Marina (7 December 2016). "The Extreme Hazing of the Most Expensive Telescope Ever Built". The Atlantic. Archived from the original on 2 February 2017. Retrieved 29 January 2017.
  135. ^ a b c d Cohen, Ben (8 July 2022). "The NASA Engineer Who Made the James Webb Space Telescope Work". Wall Street Journal. ISSN 0099-9660. Archived from the original on 11 July 2022. Retrieved 12 July 2022.
  136. ^ Potter, Sean (22 July 2022). "NASA Webb Program Director Greg Robinson Announces Retirement". NASA. Archived from the original on 23 July 2022. Retrieved 22 July 2022.
  137. ^ Wang, Jen Rae; Cole, Steve; Northon, Karen (27 March 2018). "NASA's Webb Observatory Requires More Time for Testing and Evaluation". NASA. Archived from the original on 29 March 2018. Retrieved 27 March 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  138. ^ Amos, Jonathan (27 March 2018). "Hubble 'successor' faces new delay". BBC News. Archived from the original on 28 March 2018. Retrieved 27 March 2018.
  139. ^ Witze, Alexandra (27 March 2018). "NASA reveals major delay for $8-billion Hubble successor". Nature. 556 (7699): 11–12. Bibcode:2018Natur.556...11W. doi:10.1038/d41586-018-03863-5.
  140. ^ Dreier, Casey (15 February 2019). "NASA just got its best budget in a decade". Archived from the original on 16 February 2019. Retrieved 7 March 2019.
  141. ^ Foust, Jeff (20 March 2020). "Coronavirus pauses work on JWST". SpaceNews. Archived from the original on 15 July 2022. Retrieved 15 April 2020.
  142. ^ "ESA Science & Technology – Europe's Contributions to the JWST Mission". European Space Agency. Archived from the original on 19 March 2022. Retrieved 19 December 2021.
  143. ^ "Canadian Space Agency 'Eyes' Hubble's Successor: Canada Delivers its Contribution to the World's Most Powerful Space Telescope". Canadian Space Agency. 12 April 2013. Archived from the original on 12 April 2013.
  144. ^ a b Jenner, Lynn (1 June 2020). "NASA's Webb Telescope is an International Endeavor". NASA. Archived from the original on 19 March 2022. Retrieved 23 September 2021.
  145. ^ "Meet the team: Partners and Contributors" Archived 8 January 2022 at the Wayback Machine. official NASA website of James Webb Space Telescope
  146. ^ Shepherd, Tony (25 December 2021). "James Webb: world's most powerful telescope makes its first call to Australia on Christmas Day". the Guardian. Archived from the original on 19 March 2022. Retrieved 5 January 2022.
  147. ^ Francis, Matthew. "The Problem With Naming Observatories For Bigots". Forbes. Archived from the original on 11 April 2022. Retrieved 11 April 2022.
  148. ^ Savage, Dan (21 January 2015). "Should NASA Name a Telescope After a Dead Guy Who Persecuted Gay People in the 1950s?". The Stranger. Archived from the original on 24 January 2015. Retrieved 11 April 2022.
  149. ^ a b c Oluseyi, Hakeem (23 January 2021). "Was NASA's Historic Leader James Webb a Bigot?". Medium. Archived from the original on 18 November 2021. Retrieved 18 November 2021.
  150. ^ a b Mark, Julian (13 October 2021). "NASA's James Webb telescope will explore the universe. Critics say its name represents a painful time in U.S. history". The Washington Post. Archived from the original on 13 October 2021. Retrieved 6 April 2022.
  151. ^ Mann, Adam (4 April 2022). "New Revelations Raise Pressure on NASA to Rename the James Webb Space Telescope". Scientific American. Archived from the original on 4 April 2022. Retrieved 4 April 2022.
  152. ^ Witze, Alexandra (23 July 2021). "NASA investigates renaming James Webb telescope after anti-LGBT+ claims". Nature. 596 (7870): 15–16. Bibcode:2021Natur.596...15W. doi:10.1038/d41586-021-02010-x. PMID 34302150. S2CID 236212498.
  153. ^ Overbye, Dennis (20 October 2021). "The Webb Telescope's Latest Stumbling Block: Its Name". The New York Times. Archived from the original on 20 October 2021. Retrieved 21 October 2021.
  154. ^ Overbye, Dennis (20 October 2021). "The Webb Telescope's Latest Stumbling Block: Its Name". The New York Times. Archived from the original on 20 October 2021. Retrieved 21 October 2021.
  155. ^ B. L. S, Amrit (22 October 2021). "After NASA Refuses To Rename James Webb Telescope, Advisor Quits in Protest". Archived from the original on 17 December 2021. Retrieved 17 December 2021.
  156. ^ Szkody, Paula (6 April 2022). "Presidential Action Update on JWST Naming". American Astronomical Society. Archived from the original on 7 April 2022. Retrieved 11 April 2022.
  157. ^ Tran, Tony (1 December 2021). "Influential Astronomers Call Out NASA For Telescope With Offensive Name". Futurism. Archived from the original on 18 April 2022. Retrieved 18 April 2022.
  158. ^ Mann, Adam (4 April 2022). "New Revelations Raise Pressure on NASA to Rename the James Webb Space Telescope". Scientific American. Archived from the original on 5 April 2022. Retrieved 8 April 2022.
  159. ^ Witze, Alexandra (25 March 2022). "Exclusive: Documents reveal NASA's internal struggles over renaming Webb telescope". Nature. 604 (7904): 15–16. Bibcode:2022Natur.604...15W. doi:10.1038/d41586-022-00845-6. PMID 35338365. S2CID 247713613.
  160. ^ Maggie Masetti; Anita Krishnamurthi (2009). "JWST Science". NASA. Archived from the original on 24 November 2017. Retrieved 14 April 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  161. ^ "NASA's Next Telescope Could ID Alien Megastructures". 9 February 2016. Archived from the original on 9 October 2019. Retrieved 1 September 2016.
  162. ^ Zimmer, Carl (2 July 2022). "Webb Telescope Will Look for Signs of Life Way Out There – The first question astronomers want to answer about exoplanets: Do they have atmospheres friendly to life?". The New York Times. Archived from the original on 2 July 2022. Retrieved 2 July 2022.
  163. ^ NASA's new James Webb Space Telescope will be able to sniff out methane. Here's how to tell if it's a sign of life. Archived 30 March 2022 at the Wayback Machine Stefanie Waldek, Space.com. 29 March 2022
  164. ^ "Basics of Space Flight". Jet Propulsion Laboratory. Archived from the original on 11 June 2012. Retrieved 28 August 2016. Public Domain This article incorporates text from this source, which is in the public domain.
  165. ^ Donald J. Dichmann; Cassandra M. Alberding; Wayne H. Yu (5 May 2014). "STATIONKEEPING MONTE CARLO SIMULATION FOR THE JAMES WEBB SPACE TELESCOPE" (PDF). NASA Goddard Space Flight Center. Archived from the original (PDF) on 17 December 2021. Retrieved 29 December 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  166. ^ Matt Greenhouse. "JWST Project Report to the PMC" (PDF). NASA Goddard Space Flight Center. Archived (PDF) from the original on 29 December 2021. Retrieved 29 December 2021.
  167. ^ "James Webb Space Telescope Initial Mid-Course Correction Monte Carlo Implementation using Task Parallelism Archived 19 March 2016 at the Wayback Machine" 3.1 Propulsion System Overview. J. Petersen et al. Public Domain This article incorporates text from this source, which is in the public domain.
  168. ^ Kimble, Randy (27 December 2021). "More Than You Wanted to Know About Webb's Mid-Course Corrections!". NASA. Archived from the original on 27 December 2021. Retrieved 27 December 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  169. ^ Howard, Rick, "James Webb Space Telescope (JWST)" Archived 21 December 2021 at the Wayback Machine, nasa.gov, 6 March 2012 Public Domain This article incorporates text from this source, which is in the public domain.
  170. ^ "Infrared Atmospheric Windows". Cool Cosmos. Archived from the original on 11 October 2018. Retrieved 28 August 2016.
  171. ^ a b c d "Infrared Astronomy: Overview". NASA Infrared Astronomy and Processing Center. Archived from the original on 8 December 2006. Retrieved 30 October 2006. Public Domain This article incorporates text from this source, which is in the public domain.
  172. ^ a b "Webb Science: The End of the Dark Ages: First Light and Reionization". NASA. Archived from the original on 22 November 2017. Retrieved 9 June 2011. Public Domain This article incorporates text from this source, which is in the public domain.
  173. ^ a b c d Mather, John (13 June 2006). "James Webb Space Telescope (JWST) Science Summary for SSB" (PDF). NASA. Archived (PDF) from the original on 27 March 2021. Retrieved 4 June 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  174. ^ Savage, Donald; Neal, Nancy (6 June 2003). "Webb Spacecraft Science & Operations Center Contract Awarded". NASA. Archived from the original on 3 January 2022. Retrieved 1 February 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  175. ^ "Single Board Computer". FBO Daily Issue, FBO #0332. 30 October 2002. Archived from the original on 18 May 2009. Retrieved 23 April 2008.
  176. ^ a b "Amazing Miniaturized 'SIDECAR' Drives Webb Telescope's Signal". NASA. 20 February 2008. Archived from the original on 27 February 2008. Retrieved 22 February 2008. Public Domain This article incorporates text from this source, which is in the public domain.
  177. ^ Sutherland, Scott (10 June 2022). "Webb's primary mirror was just hit by a meteoroid, but it was built to endure". The Weather Network. Archived from the original on 9 June 2022. Retrieved 10 June 2022.
  178. ^ Harwood, William (9 June 2022). "Webb telescope still performing well after micrometeoroid impact on mirror segment, NASA says". CBS News. Archived from the original on 9 June 2022. Retrieved 10 June 2022.
  179. ^ Howell, Elizabeth (18 July 2022) James Webb Space Telescope picture shows noticeable damage from micrometeoroid strike cites a NASA-ESA-CSA joint report (12 July 2022) by 611 co-authors from 44 institutions.[21]: 2 
  180. ^ a b "Ariane 5 goes down in history with successful launch of Webb". Arianespace (Press release). 25 December 2021. Archived from the original on 10 March 2022. Retrieved 25 December 2021.
  181. ^ Pinoi, Natasha; Fiser, Alise; Betz, Laura (27 December 2021). "NASA's Webb Telescope Launches to See First Galaxies, Distant Worlds – NASA's James Webb Space Telescope launched at 7:20 a.m. EST Saturday [Dec. 25, 2021] on an Ariane 5 rocket French Guiana, South America". NASA. Archived from the original on 12 April 2022. Retrieved 28 December 2021.
  182. ^ "How to track James Webb Space Telescope, mission timeline". Space Explored. 31 December 2021. Archived from the original on 1 January 2022. Retrieved 1 January 2022.
  183. ^ Achenbach, Joel (25 December 2021). "NASA's James Webb Space Telescope launches in French Guiana – $10 billion successor to Hubble telescope will capture light from first stars and study distant worlds". The Washington Post. Archived from the original on 25 December 2021. Retrieved 25 December 2021.
  184. ^ "Live Updates: Webb Telescope Launches on Long-Awaited Journey". The New York Times. 25 December 2021. Archived from the original on 25 December 2021. Retrieved 25 December 2021.
  185. ^ Overbye, Dennis; Roulette, Joey (25 December 2021). "James Webb Space Telescope Launches on Journey to See the Dawn of Starlight – Astronomers were jubilant as the spacecraft made it off the launchpad, following decades of delays and cost overruns. The Webb is set to offer a new keyhole into the earliest moments of our universe". The New York Times. Archived from the original on 29 December 2021. Retrieved 25 December 2021.
  186. ^ "Lissajous orbit". Oxford Reference. Archived from the original on 5 February 2022. Retrieved 5 February 2022.
  187. ^ "James Webb Space Telescope". blogs.nasa.gov. Archived from the original on 18 November 2021. Retrieved 22 November 2021.
  188. ^ Camera on ESC-D Cryotechnic upper stage (25 Dec 2021) view of newly separated JWST, as seen from the ESC-D Cryotechnic upper stage Archived 25 December 2021 at the Wayback Machine
  189. ^ Tereza Pultarova (25 December 2021). "'It's truly Christmas': James Webb Space Telescope's yuletide launch has NASA overjoyed". Space.com. Archived from the original on 4 January 2022. Retrieved 4 January 2022.
  190. ^ James Webb Space Telescope Deployment Sequence (Nominal), pp. 1:47, archived from the original on 23 December 2021, retrieved 23 December 2021
  191. ^ Warren, Haygen (27 December 2021). "James Webb Space Telescope en route to L2; deployment sequence underway". NASA spaceflight.com. Archived from the original on 5 January 2022. Retrieved 5 January 2022.
  192. ^ Achenbach, Joel (4 January 2022). "NASA thrilled: Webb Space Telescope deploys sun shield, evades many potential 'single-point failures'". The Washington Post. Archived from the original on 4 January 2022. Retrieved 5 January 2022.
  193. ^ a b "Gimbaled Antenna Assembly". James Webb Space Telescope. NASA. Archived from the original on 27 January 2022. Retrieved 27 December 2021.
  194. ^ Fox, Karen. "The First Mid-Course Correction Burn". NASA Blogs. Archived from the original on 26 December 2021. Retrieved 27 December 2021.
  195. ^ Fox, Karen. "Webb's Second Mid-Course Correction Burn". James Webb Space Telescope (NASA Blogs). Archived from the original on 29 December 2021. Retrieved 29 December 2021.
  196. ^ Fisher, Alise (30 December 2021). "Webb's Aft Momentum Flap Deployed". James Webb Space Telescope (NASA Blogs). Archived from the original on 30 December 2021. Retrieved 31 December 2021.
  197. ^ a b c Lynch, Patrick (31 December 2021). "With Webb's Mid-Booms Extended, Sunshield Takes Shape". James Webb Space Telescope (NASA Blogs). Archived from the original on 24 May 2022. Retrieved 1 January 2022.
  198. ^ Lynch, Patrick (31 December 2021). "First of Two Sunshield Mid-Booms Deploys". James Webb Space Telescope (NASA Blogs). Archived from the original on 29 April 2022. Retrieved 1 January 2022.
  199. ^ Fisher, Alise (5 January 2022). "Secondary Mirror Deployment Confirmed". James Webb Space Telescope (NASA Blogs). Archived from the original on 5 January 2022. Retrieved 6 January 2022.
  200. ^ Fisher, Alise (7 January 2022). "First of Two Primary Mirror Wings Unfolds". James Webb Space Telescope (NASA Blogs). Archived from the original on 7 January 2022. Retrieved 8 January 2022.
  201. ^ Fisher, Alise (8 January 2022). "Primary Mirror Wings Deployed, All Major Deployments Complete". James Webb Space Telescope (NASA Blogs). Archived from the original on 23 January 2022. Retrieved 8 January 2022.
  202. ^ Berger, Eric (8 January 2022). "Remarkably, NASA has completed deployment of the Webb space telescope". cansciencenews.com. Archived from the original on 9 January 2022. Retrieved 8 January 2022.
  203. ^ "Space telescope's 'golden eye' opens, last major hurdle". phys.org. 8 January 2022. Archived from the original on 8 January 2022. Retrieved 9 January 2022.
  204. ^ Fisher, Alise (21 January 2022). "Webb's Journey to L2 Is Nearly Complete". James Webb Space Telescope (NASA Blogs). Archived from the original on 25 January 2022. Retrieved 25 January 2022.
  205. ^ Roulette, Joey (24 January 2022). "After Million-Mile Journey, James Webb Telescope Reaches Destination – The telescope's safe arrival is a relief to scientists who plan to spend the next 10 or more years using it to study ancient galaxies". The New York Times. Archived from the original on 24 January 2022. Retrieved 24 January 2022.
  206. ^ "Orbital Insertion Burn a Success, Webb Arrives at L2 – James Webb Space Telescope". Blogs.nasa.gov. Archived from the original on 12 February 2022. Retrieved 12 February 2022.
  207. ^ "Webb Mirror Segment Deployments Complete – James Webb Space Telescope". Archived from the original on 24 January 2022. Retrieved 24 January 2022.
  208. ^ "Webb Begins Its Months-Long Mirror Alignment – James Webb Space Telescope". Archived from the original on 16 January 2022. Retrieved 17 January 2022.
  209. ^ a b c d e "Photons Incoming: Webb Team Begins Aligning the Telescope – James Webb Space Telescope". Archived from the original on 30 April 2022. Retrieved 5 February 2022. Public Domain This article incorporates text from this source, which is in the public domain.
  210. ^ "Following Webb's Arrival at L2, Telescope Commissioning Set to Begin – James Webb Space Telescope". Archived from the original on 5 February 2022. Retrieved 5 February 2022.
  211. ^ "HD 84406". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 25 January 2022.
  212. ^ Dvorsky, George (4 February 2022). "Webb Space Telescope Successfully Sees Its First Glimmer of Light – HD 84406 will go down in history as the first star spotted by the $10 billion space telescope". Gizmodo. Archived from the original on 24 February 2022. Retrieved 4 February 2022.
  213. ^ Hood, Abby Lee (6 February 2022). "The James Webb Space Telescope Just Detected Its First Signal – We're Watching The Future Unfold In Real Time". Futurism.com. Archived from the original on 19 March 2022. Retrieved 6 February 2022.
  214. ^ a b "Photons Received: Webb Sees Its First Star – 18 Times – James Webb Space Telescope". Blogs.nasa.gov. Archived from the original on 11 February 2022. Retrieved 12 February 2022.
  215. ^ "Our NIRCam instrument's detectors saw their 1st photons of starlight! While #NASAWebb is not yet ready for science, this is the first of many steps to capture images that are at first unfocused, used to slowly fine-tune the optics". Twitter.com. Archived from the original on 8 February 2022. Retrieved 12 February 2022.
  216. ^ "Webb Team Brings 18 Dots of Starlight Into Hexagonal Formation". Blogs.nasa.gov. Archived from the original on 18 February 2022. Retrieved 18 February 2022.
  217. ^ a b Webb Mirror Alignment Continues Successfully Archived 26 February 2022 at the Wayback Machine – NASA blog
  218. ^ To Find the First Galaxies, Webb Pays Attention to Detail and Theory Archived 26 February 2022 at the Wayback Machine – NASA
  219. ^ a b "2mass j17554042+6551277 – Facts about the Star". Universe Guide – Guide to Space, Planets and the Rest of the Universe. universeguide.com. 16 March 2022. Archived from the original on 15 July 2022. Retrieved 21 March 2022.
  220. ^ Kluger, Jeffrey (18 March 2022). "The James Webb Space Telescope Took Its Best Picture Yet". time.com. TIME. Archived from the original on 21 March 2022. Retrieved 21 March 2022.
  221. ^ a b Atkinson, Nancy (2 May 2022). "Now, We can Finally Compare Webb to Other Infrared Observatories". Universe Today. Archived from the original on 10 May 2022. Retrieved 12 May 2022.
  222. ^ "Calls for Proposals & Policy". Space Telescope Science Institute. Archived from the original on 15 July 2022. Retrieved 13 November 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  223. ^ "Selections Made for the JWST Director's Discretionary Early Release Science Program". Space Telescope Science Institute. Archived from the original on 8 August 2018. Retrieved 13 November 2017. Public Domain This article incorporates text from this source, which is in the public domain.
  224. ^ "Director's Discretionary Early Release Science Programs". Space Telescope Science Institute. Archived from the original on 15 July 2022. Retrieved 26 December 2021.
  225. ^ "Radiative Feedback from Massive Stars as Traced by Multiband Imaging and Spectroscopic Mosaic" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  226. ^ "IceAge: Chemical Evolution of Ices during Star Formation" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  227. ^ "Through the Looking GLASS: A JWST Exploration of Galaxy Formation and Evolution from Cosmic Dawn to Present Day" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  228. ^ "A JWST Study of the Starburst-AGN Connection in Merging LIRGs" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  229. ^ "The Resolved Stellar Populations Early Release Science Program" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  230. ^ Dominika Wylezalek. "Q-3D: Imaging Spectroscopy of Quasar Hosts with JWST Analyzed with a Powerful New PSF Decomposition and Spectral Analysis Package" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  231. ^ "The Cosmic Evolution Early Release Science (CEERS) Survey" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  232. ^ "Establishing Extreme Dynamic Range with JWST: Decoding Smoke Signals in the Glare of a Wolf-Rayet Binary" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  233. ^ "TEMPLATES: Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  234. ^ "Nuclear Dynamics of a Nearby Seyfert with NIRSpec Integral Field Spectroscopy" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  235. ^ "The Transiting Exoplanet Community Early Release Science Program" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  236. ^ "ERS observations of the Jovian System as a Demonstration of JWST's Capabilities for Solar System Science" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  237. ^ "High Contrast Imaging of Exoplanets and Exoplanetary Systems with JWST" (PDF). Archived (PDF) from the original on 15 July 2022. Retrieved 17 March 2022.
  238. ^ "JWST Cycle 1 General Observer Submission Statistics". Space Telescope Science Institute. Archived from the original on 15 July 2022. Retrieved 10 January 2022.
  239. ^ "STScI Announces the JWST Cycle 1 General Observer Program". Archived from the original on 15 July 2022. Retrieved 30 March 2021.
  240. ^ Chow, Denise; Wu, Jiachuan (12 July 2022). "Photos: How pictures from the Webb telescope compare to Hubble's - NASA's $10 billion telescope peers deeper into space than ever, revealing previously undetectable details in the cosmos". NBC News. Archived from the original on 15 July 2022. Retrieved 16 July 2022.
  241. ^ Deliso, Meredith; Longo, Meredith; Rothenberg, Nicolas (14 July 2022). "Hubble vs. James Webb telescope images: See the difference". ABC News. Archived from the original on 15 July 2022. Retrieved 15 July 2022.
  242. ^ a b Garner, Rob (11 July 2022). "NASA's Webb Delivers Deepest Infrared Image of Universe Yet". NASA. Archived from the original on 12 July 2022. Retrieved 12 July 2022.
  243. ^ a b Overbye, Dennis; Chang, Kenneth; Tankersley, Jim (11 July 2022). "Biden and NASA Share First Webb Space Telescope Image – From the White House on Monday, humanity got its first glimpse of what the observatory in space has been seeing: a cluster of early galaxies". The New York Times. Archived from the original on 12 July 2022. Retrieved 12 July 2022.
  244. ^ Pacucci, Fabio (15 July 2022). "How Taking Pictures of 'Nothing' Changed Astronomy - Deep-field images of "empty" regions of the sky from Webb and other space telescopes are revealing more of the universe than we ever thought possible". Scientific American. Archived from the original on 16 July 2022. Retrieved 16 July 2022.
  245. ^ Kooser, Amanda (13 July 2012). "Hubble and James Webb Space Telescope Images Compared: See the Difference - The James Webb Space Telescope builds on Hubble's legacy with stunning new views of the cosmos". CNET. Archived from the original on 17 July 2022. Retrieved 16 July 2022.
  246. ^ Timmer, John (8 July 2022). "NASA names first five targets for Webb images". Ars Technica. Archived from the original on 8 July 2022. Retrieved 8 July 2022.
  247. ^ a b "First Images from the James Webb Space Telescope". NASA. 8 July 2022. Archived from the original on 13 July 2022. Retrieved 8 July 2022.
  248. ^ Stirone, Shannon (12 July 2022). "Gawking in Awe at the Universe, Together". The New York Times. Archived from the original on 15 July 2022. Retrieved 13 July 2022.
  249. ^ Dennis Overbye; Kenneth Chang; Joshua Sokol (12 July 2022). "Webb Telescope Reveals a New Vision of an Ancient Universe". Archived from the original on 15 July 2022. Retrieved 13 July 2022.
  250. ^ Chang, Kenneth (15 July 2022). "NASA Shows Webb's View of Something Closer to Home: Jupiter - The powerful telescope will help scientists make discoveries both within our solar system and well beyond it". The New York Times. Archived from the original on 16 July 2022. Retrieved 16 July 2022.
  251. ^ Astudillo-Defru, N.; Cloutier, R.; Wang, S. X.; Teske, J.; Brahm, R.; Hellier, C.; Ricker, G.; Vanderspek, R.; Latham, D.; Seager, S.; Winn, J. N.; et al. (1 April 2020). "A hot terrestrial planet orbiting the bright M dwarf L 168-9 unveiled by TESS". Astronomy and Astrophysics. 636: A58. arXiv:2001.09175. Bibcode:2020A&A...636A..58A. doi:10.1051/0004-6361/201937179. ISSN 0004-6361. S2CID 210920549. Archived from the original on 8 March 2022. Retrieved 15 July 2022.
  252. ^ "Scottish astronomers push James Webb deeper back in time". BBC News. 26 July 2022. Archived from the original on 26 July 2022. Retrieved 26 July 2022.

Further reading

External links