Hayabusa2 (はやぶさ2) is a mission to survey a near-Earth asteroid and collect a surface sample for return to Earth in 2021. The spacecraft arrived at asteroid 162173 Ryugu (just ‘Ryugu’ for short) on 27 June 2018. Asteroids like Ryugu are time capsules that can teach us more about the origin and evolution of the solar system. Learning about them also helps efforts to defend Earth from potential asteroid impacts.
The spacecraft has 4 deployable surface landers — 3 of which have already been deployed — as well as an explosive device to generate a crater, and target markers containing names collected by The Planetary Society.
Hayabusa2 is a follow-on mission to JAXA’s successful Hayabusa, which visited S-type asteroid (25143) Itokawa and returned a sample on 13 June 2010. Hayabusa’s samples proved that S-type asteroids (the most common in the near-Earth asteroid population) are the parents of ordinary chondrite meteorites.
Hayabusa2’s goal is to sample a member of different near-Earth asteroid population, a C-type asteroid. The mission has four science objectives (Watanabe et al. 2017):
Find out how dynamic the early solar system was by studying how different kinds of materials (rocky matter, organic matter, ices, etc.) are distributed and layered on Ryugu
Study the chemical reactions among minerals, ices, and organic material that happened during solar system formation by searching for organic materials in returned samples, and finding out which kinds of minerals coexist with them
Do radioisotope age dating on the returned samples to find out when the asteroid’s materials formed and when significant heating happened in the past
Map Ryugu’s surface and tell its geologic story, especially its impact history
Hayabusa2 components, top view
Hayabusa2 components, bottom view
Central core: 1 meter wide, 1.25 meters tall, 1.6 meters deep
Width with solar panels: 6 meters
Length of sample horn: 1 meter
Mass: 600 kg fueled
Optical Navigation Camera - Telescopic (ONC-T, a.k.a. multiband imager): Camera for close-up views of Ryugu in visible and near-infrared light. 7 color filters: 390 (UV), 480 (blue), 550 (green), 700 (red), 860 (near IR), 950 (IR), 589.5 (clear). 1024 pixels square, FOV 5.7 degrees square, pixel scale 97.15 μrad. Hayabusa heritage with slight filter differences. Principal investigator: Seiji Sugita. Yoshikawa et al. (2014) | Suzuki et al. (2018) | Kameda et al. (2017) | July 2018 fact sheet
Optical Navigation Camera - Wide Angle (ONC-W1, ONC-W2): Cameras for wide-angle views of Ryugu in visible light. Monochrome (broadband 485-655 nm), 1024 pixels square, FOV 65.24 degrees square, pixel scale 1.19 μrad. Hayabusa heritage. Principal investigator: Seiji Sugita. Suzuki et al. (2018) | July 2018 fact sheet
Laser altimeter (LIDAR): Used to create a 3D map of Ryugu. Works within 25 kilometers, down to 30 meters. Within 30 meters, the spacecraft switches to a Laser Range Finder (LRF). Hayabusa heritage. Principal investigator: Noriyuki Namiki. Yoshikawa et al. (2014) | Yamada et al. (2017) | Mizuno et al. (2017) | TPS correspondence with JAXA
Thermal Infrared Imager (TIR): Used to measure asteroid surface temperatures. Wavelength 8 – 12 pm, FOV 12 x 16 degrees, 320 x 240 pixels. Akatsuki heritage, swapped for X-ray Fluorescence Spectrometer (XRS) on Hayabusa. Principal investiagor: Satoshi Tanaka. Okada et al. (2017) | Yoshikawa et al. (2014) | July 2018 fact sheet
Near-infrared spectrometer (NIRS3): Investigates mineral composition and distribution on Ryugu’s surface. Wavelength 1.8 – 3.2 pm, FOV 0.1 deg x 0.1 degrees. Hayabusa heritage with different wavelength. Principal investigator: Kohei Kitazato. Iwata et al. (2017) | Yoshikawa et al. (2014) | July 2018 fact sheet
Small carry-on impactor (SCI): Used to create an artificial crater on Ryugu’s surface, uncovering materials not currently exposed to space. Consists of a small deployable box of explosives and a lump of copper (used to differentiate the impactor from native Ryugu materials). Hayabusa2 will release the explosive box, fire its reaction control thrusters, and hide behind Ryugu while the box explodes and shoots the copper lump into the surface at about 2 kilometers per second, creating a crater a few meters in diameter. Principal investigator: Masahiko Arakawa. Saiki et al. (2017) | Yoshikawa et al. (2014) | Tsuda et al. (2013) | July 2018 fact sheet
Deployable Camera 3 (DCAM3): After deploying SCI, several tens of minutes before the explosion, Hayabusa2 will release this instrument, a cylinder 78 mm in diameter and 80 mm tall. It contains two cameras to capture the explosion and crater formation: a low-resolution analog imager that will transmit to Hayabusa2 in real-time (DCAM3-A, color, viewing angle 71º x 53º, 720 x 526 pixels, resolution 10 m/pixel) and one high-resolution digital imager that will send data to Hayabusa2 after the crater impact (DCAM-3-D, monochrome, viewing angle 74º x 74º, 2000 x 2000 pixels, resolution 1m/pixel). The system is IKAROS heritage. A separate component on the spacecraft will receive the DCAM3 images and also has a small camera head (DCAM3-CAM-H) that can take images of the Hayabusa2 sampler horn. Sawada et al. (2017) | Ogawa et al. (2017) | Ishibashi et al. (2017)
Hayabusa2’s sample system is similar to that of Hayabusa, with minor improvements. The system consists of a one-meter-long sample horn, a sample catcher, a sample container, and an Earth re-entry capsule.
When Hayabusa2’s sample horn touches the surface, it fires a tantalum projectile into the surface within the sample horn, kicking up surface material. The use of tantalum allows sample material to be distinguished easily from impactor material. The material floats up the horn, through a 90-degree turn, and into a sample catcher. Just 1 second after touchdown, the spacecraft fires its thrusters for ascent to avoid tipping over. The sample horn also contains a catch at the bottom opening to allow small pieces of gravel to stay in the horn. When Hayabusa2 decelerates, any caught gravel pieces can tumble up the horn into the sample catcher. The catcher itself has 3 collection compartments.
Hayabusa2's touchdown and sample collection site, L08-E1, is located on Ryugu's equator, roughly between Kintaro crater to the west and Brabo crater to the east. It was chosen for safety reasons, because it had no rocks larger than 60 centimeters, and was closer to a target marker the team previously dropped.
JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST / Processed by Jason Davis
Ryugu landing site
This sequence of images was captured during Hayabusa2's second touchdown rehearsal on 15 October 2018. Landing site L08-E1 was highlighted in blue by Jason Davis.
MINERVA-II: Hayabusa2 carries three drum-shaped rovers designed to hop across Ryugu. MINERVA-II-1 consists of two rovers: Rover-1A and Rover-1B. Both were successfully deployed on 21 September 2018. MINERVA-II-2 is a third, larger rover that isn’t believed to be working properly, but may be deployed anyway. Principal investigator: Hirohide Demura.