“All observations [including the ones of MASCOT] indicate Ryugu to be rocky all over,” Ho said. “There seem to be no wide, smooth terrains. However, for the safe landing and sampling maneuver of Hayabusa2, a safe landing area of [only] 100 meters [330 feet] is required.”
The spacecraft needs to carefully choose a spot that’s relatively clear of boulders. The difficulty will be to find a 100-meter area with boulders that are smaller than 50 centimeters to aid with sample collection.
“Unlike other asteroids we have visited, Ryugu has no powder, no fine-grain regolith. That makes selecting a place to sample more challenging,” said Deborah Domingue, a member of the Hayabusa2 science team. “We are helping characterize the surface to optimize landing site selection.”
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While MASCOT travels on Ryugu are complete, its design could be adapted to visit one of Mars’s moons — Phobos or Deimos. These Martian moons have never had a surface mission, although images of them have been captured during spacecraft flybys. Germany, Japan, and France are developing a Phobos rover to fly on a future Japanese mission called Martian Moons eXploration, set to launch in the early 2020s.
MASCOT was a hopper, but the Phobos rover will be more of a driver.
“Based on the higher gravity on Phobos, the engineers decided for the wheeled locomotion system,” Ho said. But on worlds with lower gravity, MASCOT's design would be helpful — although Ho noted that a longer battery life would be would be critical to collecting more data.
Hayabusa2 has been doing some landing practice runs in the last while, but soon it will turn its attention to two months of automated science operations. This is because Ryugu has grown too close to the sun for Earth’s radio commands to safely transmit without interference. Detailed science operations will resume afterwards.