هایابوسا ۲ (به ژاپنی: はやぶさ 2)، (به انگلیسی: Hayabusa two)، یک مأموریت بازگرداندن نمونهٔ سیارک ریوگو ۱۶۲۱۷۳ توسط آژانس فضایی ژاپن، جاکسا است. این مأموریت ادامهٔ برنامهٔ هایابوسا و با توجه به نقاط ضعف و موفقیتهای آن فضاپیما و استفاده از درسهای آموخته شده از آن مأموریت است. این فضاپیما در ۲۷ ژوئن ۲۰۱۸ به ریوگو ۱۶۲۱۷۳ رسید. این فضاپیما سیارک را برای یک سال و نیم بررسی خواهد کرد. در دسامبر 2019 از مدار این سیارک خارج میشود و در دسامبر 2020 به زمین باز میگردد.
هایابوسا ۲ چندین بار علمی برای سنجش از راه دور، نمونه برداری، و همچنین چهار دستگاه سطحنورد کوچک با خود دارد که از آنها برای بررسی سطح سیارک و کسب اطلاعات محیط زیستی و زمین شناسی نمونههای جمع آوری شده و بررسی آنها استفاده میکند.
هدف این مأموریت سیارک ۱۶۲۱۷۳ ریوگو است که قبلاً به نام ۱۹۹۹ JU3 ثبت شدهبود. هایابوسا۲ برابر با برنامهٔ پیشبینی شده در ۲ ژوئیهٔ سال ۲۰۱۸، به هدف رسید تا برای یک سال و نیم به بررسی این سیارک بپردازد، در دسامبر ۲۰۱۹ سیارک را ترک کند. بازگشت آن به زمین در دسامبر سال ۲۰۲۰ خواهد بود.
این فضاپیما ویژگیهای از موتورهایی با پیشرانه یونی، تکنولوژی هدایت و ناوبری پیشرفته و به روز شده، آنتن و سیستمهای تنظیم حالت برخوردار است. عملیاتی که در سیارک ریوگو انجام خواهد شد مشابه مأموریت هایابوسای پیشین است، با این تفاوت که اینبار با یک وسیله انفجاری به حفاری در سطح سیارک برای دسترسی به مواد نمونهٔ تازه نیز اقدام خواهد شد.
پس از موفقیت نسبی هایابوسا، جاکسا شروع به بررسی یک مأموریت جانشین احتمالی در سال ۲۰۰۷ کرد. در ژوئیه ۲۰۰۹، مکوتو یوشیکاوا (Makoto Yoshikawa) از بنیاد جاکسا پیشنهادی با عنوان «ادامهٔ مأموریت بازگرداندن نمونهٔ هایابوسا» تهیه و ارائه داد. در اوت ۲۰۱۰، جاکسا تأیید دولت ژاپن را برای آغاز ایجاد و تکمیل هایابوسا۲ دریافت کرد. هزینهٔ برآورد شدهٔ پروژه در سال ۲۰۱۰ برابر ۱۶٫۴ میلیارد ین (۱۴۶ میلیون دلار آمریکا) بود.
Hayabusa2 (Japanese: はやぶさ2, "Peregrine falcon-2") is an asteroid sample-return mission operated by the Japanese space agency, JAXA. It follows on from the Hayabusa mission which returned asteroid samples in 2010. Hayabusa2 was launched on 3 December 2014 and rendezvoused with near-Earth asteroid 162173 Ryugu on 27 June 2018. It is in the process of surveying the asteroid for a year and a half, departing in December 2019, and returning to Earth in December 2020.
Hayabusa2 carries multiple science payloads for remote sensing, sampling, and four small rovers that are investigating the asteroid surface to inform the environmental and geological context of the samples collected.
Asteroid 162173 Ryugu (formerly designated 1999 JU3) is a primitive carbonaceous near-Earth asteroid. Carbonaceous asteroids are expected to preserve the most pristine materials in the Solar System, a mixture of minerals, ice, and organic compounds that interact with each other. Studying it is expected to provide additional knowledge on the origin and evolution of the inner planets and, in particular, the origin of water and organic compounds on Earth, all relevant to the origin of life on Earth.
Initially, launch was planned for 30 November 2014, but was delayed to 3 December 2014 04:22 UTC (4 December 2014 13:22:04 local time) on a H-IIA launch vehicle. Hayabusa2 arrived at Ryugu on 27 June 2018, and it is expected to survey the asteroid for a year and a half during which time it collected samples. The mission plan calls for it to depart in December 2019, and return the samples to Earth in December 2020.
Compared to the previous Hayabusa mission, the spacecraft features improved ion engines, guidance and navigation technology, antennas, and attitude control systems. A kinetic penetrator was shot into the asteroid to expose pristine sample material that was later sampled for return to Earth.
On 21 September 2018, the Hayabusa2 spacecraft ejected the first two rovers, Rover-1A and Rover-1B, from about 55 meters altitude that fell independently to the surface of the asteroid. They functioned nominally and transmitted data. The MASCOT rover deployed successfully on 3 October 2018 and operated for about 16 hours as planned.
The first sample collection was scheduled to start in late October 2018, but the rovers encountered a landscape with large and small boulders but no regolith to sample, so the mission team decided to postpone the sample acquisition to 2019 and evaluated several options. Its first surface sample retrieval took place on 21 February 2019. On 5 April 2019, Hayabusa2 released an impactor and created an artificial crater on the asteroid surface. Hayabusa2 failed on 14 May to drop off reflective markers necessary for descent and sampling, but it successfully dropped off one reflective marker from an altitude of 9 meters on 4 June. The sub-surface sampling took place on 11 July 2019.
Funding and history
Following the partial success of Hayabusa, JAXA began studying a potential successor mission in 2007. In July 2009, Makoto Yoshikawa of JAXA presented a proposal titled "Hayabusa Follow-on Asteroid Sample Return Missions". In August 2010, JAXA obtained approval from the Japanese government to begin development of Hayabusa2. The cost of the project estimated in 2010 was 16.4 billion yen (US$149 million).
Hayabusa2 was launched on 3 December 2014, arrived at asteroid Ryugu on 27 June 2018, and remained at a distance of about 20 km to study and map the asteroid. In the week of 16 July 2018, operations were begun to lower this hovering altitude. On 21 September 2018, Hayabusa2 ejected the first two rovers, Rover-1A and Rover-1B, from an altitude of about 55 meters to the surface of the asteroid.
The design of Hayabusa2 is based on the first Hayabusa spacecraft, with some matured improvements. It has a mass of 610 kg (1,340 lb) with fuel, and electric power is generated by bilateral solar arrays with an efficiency of 2.6 kW at 1 AU, and 1.4 kW at 1.4 AU. The power is stored in eleven inline-mounted 13.2 Ah lithium ion batteries.
The spacecraft features four solar-electric ion thrusters for propulsion called μ10, one of which is a backup. These engines use microwaves to convert xenon into plasma (ions), which is accelerated by applying a voltage from the solar panels and ejected out the back of the engine. The simultaneous operation of three engines generates thrusts of up to 28 mN. Although this thrust is very small, the engines are also extremely efficient; the 66 kg of xenon reaction mass can change the speed of the spacecraft by up to 2 km/s (4,500 mph).
The spacecraft has four redundant reaction wheels and a chemical reaction control system featuring twelve thrusters for attitude control (orientation) and orbital control at the asteroid. The chemical thrusters use hydrazine and MON-3, with a total mass of 48 kg of chemical propellant.
The spacecraft has two high-gain directional antennas for X band and Ka band. Bit rates are 8 bit/s–32 kbit/s. The ground stations are the Usuda Deep Space Center, Uchinoura Space Center, NASA Deep Space Network and ESA's Malargü Station.
The optical navigation camera telescope (ONC-T) is a telescopic framing camera with seven colors to optically navigate the spacecraft. It works in synergy with the optical navigation camera wide-field (ONC-W2) and with two star trackers.
In order to descend to the asteroid surface for sampling, the spacecraft released one of five target markers in the selected landing zones as artificial landmark with highly reflective outer material that is recognized by a strobe light mounted on the spacecraft. The spacecraft also used its laser altimeter and ranging (LIDAR) and other sensors during sampling.
The Optical Navigation Cameras (ONCs) are used for spacecraft navigation during the asteroid approach and proximity operations. They also remotely image the surface and search for interplanetary dust around the asteroid. ONC-T is a telephoto camera with a 6.35°×6.35° field of view and several optical filters carried in a carousel. ONC-W1 and ONC-W2 are wide angle (65.24°×65.24°) panchromatic (485–655 nm) cameras of nadir and oblique views, respectively.
The Near-Infrared Spectrometer (NIRS3) is a spectrograph operating at wavelengths 1.8–3.2 μm, intended for analysis of surface mineral composition.
The Thermal-Infrared Imager (TIR) is a thermal infrared camera working at 8–12 μm, using a two-dimensional microbolometer array. Its spatial resolution is 20 m at 20 km distance or 5 cm at 50 m distance. It will be able to determine surface temperatures in the range -40–150 °C.
The Light Detection And Ranging (LIDAR) instrument is measuring the distance from spacecraft to the asteroid surface by measuring the time of flight of laser light reflection. It operates over the altitude range 30 m–25 km.
When the spacecraft is closer to the surface than 30 m during the sampling operation, Laser Range Finders (LRF-S1, LRF-S3) are used to measure the distance and the attitude of spacecraft relative to the terrain. Another device LRF-S2 monitors the sampling horn to trigger the sampling projectile.
LIDAR and ONC data will be combined to determine the detailed topography (dimensions and shape) of the asteroid. Monitoring of a radio signal from Earth allows measurement of the asteroid's gravitational field.
Hayabusa2 carries four small rovers to investigate the asteroid surface in situ, and provide context information for the returned samples. All four rovers move around by short hops, and none is equipped with wheels due to the minimal gravity of the asteroid. They were deployed at different dates from about 60 m altitude and fell freely to the surface under the asteroid's weak gravity. The first two rovers landed on asteroid Ryugu on 21 September 2018.
MINERVA-II is a successor to the MINERVA lander carried by Hayabusa. It consists of several separate subsystems.
MINERVA-II-1 is a container that deployed two rovers, Rover-1A (HIBOU) and Rover-1B (OWL), on 21 September 2018. It was developed by JAXA and the University of Aizu. The rovers are identical with a cylindrical shape, 18 cm diameter and 7 cm tall, and a mass of 1.1 kg (2.4 lb) each. They move by hopping in the low gravitational field, using a torque generated by rotating masses within the rovers. Their scientific payload is a stereo camera, wide-angle camera, and thermometers. Solar cells and double-layer capacitors provide the electrical power.
The MINERVA-II-2 container holds the ROVER-2, developed by a consortium of universities led by Tohoku University in Japan. This is an octagonal prism shape, 15 cm diameter and 16 cm tall (5.9 × 6.3 in), with a mass of about 1 kg (2.2 lb). It has two cameras, a thermometer and an accelerometer. It has optical and ultraviolet LEDs for illumination to detect floating dust particles. ROVER-2 carries four mechanisms to hop and relocate.
The Mobile Asteroid Surface Scout (MASCOT) was developed by the German Aerospace Center in cooperation with the French space agency CNES. It measures 29.5 cm × 27.5 cm × 19.5 cm and has a mass of 9.6 kg (21 lb). MASCOT carries four instruments: an infrared spectrometer (MicrOmega), a magnetometer (MASMAG), a radiometer (MARA), and a camera (MASCAM) that imaged the small-scale structure, distribution and texture of the regolith. The rover is capable of tumbling once to reposition itself for further measurements. It collected data on the surface structure and mineralogical composition, the thermal behaviour and the magnetic properties of the asteroid. It has a non-rechargeable battery that allowed for operations for approximately 16 hours.[failed verification] The infrared radiometer on the InSight Mars lander, launched in 2018, is based on the MASCOT radiometer.
Objects deployed by Hayabusa2
The original plan was for the spacecraft to collect up to three samples: 1) surface regolith that exhibits traits of hydrous minerals; 2) surface regolith with either unobservable or weak evidence of aqueous alterations; 3) excavated sub-surface material. The first two surface samples were scheduled to start in late October 2018, but the rovers show a scenery of large and small boulders and no regolith to sample, so the mission team decided to postpone sampling to 2019 and evaluate several options. The first surface sampling was completed in February 22 and obtained a substantial amount of regolith, so the second surface sampling was postponed and was eventually cancelled to decrease risk to the mission.
The second and final sample was of excavated material dislodged by a kinetic impactor shot from a distance (SCI impactor). All samples are stored in separate sealed containers inside the sample return capsule.
Hayabusa2's sampling device is based on Hayabusa's. Its first surface sample retrieval was conducted on 21 February 2019, which began with the spacecraft's descent, approaching the surface of the asteroid. When the sampler horn attached to Hayabusa2's underside touched the surface, a projectile (5-gram tantalum bullet) was fired at 300 m/s into the surface. The resulting ejecta particles were collected by a catcher at the top of the horn, which the ejecta reached under their own momentum under microgravity conditions.
The sub-surface sample collection required an impactor to excavate a crater to eventually obtain material deeper from the sub-surface, which has not been subjected to space weathering. This required removing a large volume of surface material with a substantial impactor. For this purpose, Hayabusa2 deployed on April 5 a free-flying gun with one "bullet", called the Small Carry-on Impactor (SCI); the system consists of a 2.5 kg (5.5 lb) copper projectile shot to the surface by an explosive propellant charge. Following SCI deployment, Hayabusa2 also left behind a deployable camera (DCAM3)[Note 2] to observe and map the precise location of the SCI impact, while the orbiter maneuvered to the far side of the asteroid in order to avoid debris from the impact.
Approximately 40 minutes after separation, when the spacecraft was at a safe distance, the penetrator was fired into the asteroid surface by the detonation of 4.5 kg (9.9 lb) shaped charge of plasticized HMX for acceleration. The copper impactor was shot to the surface from an altitude of about 500 meters and it excavated a crater of about 10 meters in diameter, exposing pristine material. The next step was the deployment on 4 June of a reflective target marker in the area near the crater to assist with navigation and descent. The touchdown and sampling took place on 11 July 2019.
The spacecraft collected and stored the samples in separate sealed containers inside the sample-return capsule (SRC), which has a thermal insulation, 40 cm external diameter, 20 cm in height, and a mass of ~16 kg.
At the end of the science phase in December 2019, Hayabusa2 will use its ion engines for changing orbit and return to Earth. When Hayabusa2 flies past Earth in December 2020, it will release the capsule spinning at one revolution per three seconds. The capsule will re-enter the Earth's atmosphere at 12 km/s and it will deploy a radar-reflective parachute at an altitude of about 10 km, and eject its heat-shield, while transmitting a position beacon signal. The sample capsule will land at the Woomera Test Range in Australia. The total flight distance would be 5,240,000,000 km.
Once on Earth, any volatile substance will be collected before the sealed containers are opened. The samples will be curated and analyzed at JAXA's Extraterrestrial Sample Curation Center, where international scientists can request a small portion of the samples.
Potential mission extension
When the spacecraft returns and flies past Earth to deliver the sample capsule in December 2020, it is expected to retain 30 kg of xenon propellant, which can be used to extend its service and flyby new targets to explore. One prime candidate is asteroid 2001 WR1 for a flyby on 27 June 2023.
Japanese minor body probes