KNOXVILLE, Tenn. – Japan's Hayabusa2 spacecraft is getting ready to touch down on asteroid Ryugu, where it will scoop a…
KNOXVILLE, Tenn. – Japan’s Hayabusa2 spacecraft is getting ready to touch down on asteroid Ryugu, where it will scoop a sample of the asteroid’s rocky surface that will eventually be sent back to Earth.
After narrowing down the possible landing sites for Hayabusa2, mission scientists performed a sampling rehearsal on Wednesday (Oct. 24) at 10:47 p.m. EST (0247 GMT on Oct. 25), and the mission is “ramping up the steps towards a successful touchdown,” Masaki Fujimoto of the Japan Aerospace Exploration Agency (JAXA) said at a news conference here at the 50th meeting of the American Astronomical Society’s Division for Planetary Sciences (DPS).
At that time, the spacecraft descended to an altitude of 7.5 miles (1
2 miles) above the asteroid’s surface and deployed a small target marker at the landing site, Fujimoto said. go all the way down to the surface to retrieve a sample no earlier than January 2019, and that sample will land in Australia in 2020. [Japan’s Hayabusa2 Asteroid Ryugu Sample-Return Mission in Pictures]
The Hayabusa2 mission has already deployed two small jumping robbers (MINERVA-II1A and MINERVA-II1B) and a German lander called the Mobile Asteroid Surface Scout (MASCOT) on Ryugu within the past month. Mens de MINERVA rovers still scouting Ryugu’s surface, MASCOT’s mission was short-lived, ending after only 17 hours and 7 minutes. MASCOT was designed to last only 16 hours on Ryugu’s surface.
“The mission focus is now on the successful retrieval and return of a surface sample,” officials with the Planetary Science Institute, which is involved with the Hayabusa2 mission, said in a statement. To ensure that this phase of the mission will be a success, mission scientists had to pick a landing site that is not only interesting from a scientific perspective, but that is also safe for the spacecraft – something that proved to be more difficult than mission controllers initially expected.
When Hayabusa2 snapped its first detailed images of Ryugu in June, scientists were “shocked” to find that it’s basically a cluster of rubble rather than a smooth, dusty space rock like the asteroid Itokawa (which the original Hayabusa mission visited in 2005) and Eros, Fujimoto said. “That was the moment we realized this was not going to be an easy mission,” he said, adding that Ryugu’s rocky surface is “not friendly to the mission.”
This view of asteroid Ryugu is the highest resolution image ever taken or an asteroid. Hayabusa2 captured the image with its Optical Navigation Camera on Oct. 15, 2018, from an altitude of 138 feet (42 meters).
Credit: JAXA / Tokyo University / Kochi University / Rikkyo University / Nagoya University / Chiba Institute of Technology / Meiji University / Aizu University / AIST
Scientists working on the Hayabusa2 were not prepared for the lack of safe landing sites on Ryugu, because they based their expectations of asteroid Ryugu on past experience, Fujimoto said. “It’s not easy to reveal the stupidity that we have been in, but we thought we had good experience with Itokawa … and there was some smooth terrain on the surface , and we thought that’s the way it should be. There might be some rocky part, but there should be some smoother part and that was the expectation. “
” This is this is part of why we explore – to see the unexpected and to go ahead and forge ahead and do what we plan to do, return a sample, “Deborah Domingue, a participating scientist for Hayabusa2 with the Planetary Science Institute, said in the news conference. “It never meets our expectations where we go, and that’s the excitement.”
Ryugu’s inhospitable terrain proved to be problematic when MASCOT came in for a bumpy landing on Oct. 2. On its way down, the hopping rover crashed into a rock and wound upside down with its instruments pointing out into space rather than down at the asteroid’s surface, Ralf Jaumann, a principal investigator with the Hayabusa2 mission from the German Aerospace Center (DLR), said at the news conference. Heldigvis var rocken “ikke så hard”, Jaumann sa, og kommandokontrollere var i stand til å flip the rover over og utføre alle de undersøkelser som planlagt.
Hayabusa2’s target markers are small, white balls about 4 inches (10 centimeters) in diameter. They are covered in a reflective film to make them visible to the Hayabusa2 spacecraft, which will use them to navigate during its descent for the sample return phase of the mission.
To find potential sampling sites for Hayabusa2, scientists created topographic models of Ryugu’s surface using images from the MINERVA and MASCOT landers and looked for the smoothest areas on the asteroid’s surface. “It’s pretty much boulders everywhere,” said Lucille Le Corre, another participating scientist with the Planetary Science Institute. “
In addition to the images, scientists are using Hayabusa2’s Thermal Infrared Imager (TIR) instrument to learn more about the size and other properties of materials on the asteroid’s surface. Specifically, TIR is looking for grains of dust and dirt like those seen on other asteroids and on the moon.
The Hayabusa2 team started out by selecting a square-shaped landing area measuring about 590 feet (180 meters) wide, and they have recently narrowed it to a circle about 66 feet (20 m) in diameter. Nå, det neste trinnet er å jobbe med å forbedre romfartøyets navigasjonsnøyaktighet, “så det kan trekke seg i hullet,” sier Fujimoto. Fordi Ryugu er ved at passere rundt på den motsatte siden av solen, forårsaker Hayabusa2 to temporarily lose contact with Earth, “that leaves two months of time for the team to think about the details of the touchdown operations.”