Asteroid Ryugu Poses Landing Risks for Japanese Mission

scientific american ^ | August 23, 2018 | Davide Castelvecchi, Nature magazine on

[BenLurkin]

After inspecting asteroid Ryugu for two months, the Japan Aerospace Exploration Agency (JAXA) has revealed the sites where the Hayabusa2 spacecraft will touchdown to collect a sample to bring back to Earth—and also where it will drop the first two of its planned landing probes.

…

Hayabusa2 is the follow-up mission to Hayabusa, a probe that was the first to collect samples from an asteroid and bring them back to Earth in 2010....

Since then, Hayabusa2 has been hovering a few tens of kilometres above the space rock and scanning its surface as it revolves every seven-and-a-half hours. The spacecraft also made a closer approach earlier this month, temporarily letting itself fall down to an altitude 851 metres. By measuring the speed of that free fall, mission control was able to estimate the mass of the asteroid, at about 450 million tonnes.

Hayabusa2 carries three landers that it will eject to the asteroid over its mission. It will also touch down itself to collect samples to return to Earth. In today’s press conference, members of the mission team described how they picked the sites for the first of two touchdowns and for releasing MASCOT—a lander built by the French and German space agencies—and the first of the two MINERVA-II landers, built by a Japanese consortium.

In early October, Hayabusa will temporarily fly down to an altitude of 60 metres to drop MASCOT. The operation will involve some risk: the shoebox-sized lander does not have the ability to steer itself, and mission control can predict where it will hit the ground only within a region around 70 metres wide. After that first impact—at a leisurely speed of around 30 centimetres per second—MASCOT will bounce in an unpredictable direction, and its final arrival place is even more uncertain, by hundreds of metres.

[Dagnabitt]

Cool mission. There was also landing on a comet a few years ago IIRC.

[Calvin Locke]

Which landing? The US had a mission to one to observe/shadow, and at the end of mission/fuel, the craft touched down on it. Somewhere along the line, after the accidental vehicular death of Gene Shoemaker, the probe was named after him.

In the original Hayabusa mission, it touched down, but JAXA neglected to take into account the [actual?] amount of force the scoop exerted when it did its thing, so the craft got pushed off. Yes, it did get some material, but the fine folks at JAXA held their collective breaths until the return.

[ADemocratNoMore]

The original probe did land on an asteroid back in 2005 and is a testament to the engineer’s ability to deal with a host of unexpected problems that cropped up during the mission, any one of which could have doomed the mission.

You’ve gotta love the Japanese - they write love songs to space probes. The story of the original mission is told in the following song...

https://www.youtube.com/watch?v=i28iBZx-W_E

It includes English captions and at about 3:20 there is a detailed list of all the failures that it overcame on it’s mission.

Here’s another version of the last song without any English translation but if you watch the first video you should understand what’s going on here...

https://www.youtube.com/watch?v=tiCS5Gv63m0

[Smellin Salt]

Rosetta

[Vince Ferrer]

If these asteroid probes don’t seem exiting compared to the moon or Mars, these asteroids have trillions of dollars of metals, water, and everything we need to build cities in space. This will fund the expansion out into the solar system.

[Dagnabitt]

Yes, ESA’s Rosetta mission.

[Vince Ferrer]

If these asteroid probes don’t seem exiting compared to the moon or Mars, these asteroids have trillions of dollars of metals, water, and everything we need to build cities in space. This will fund the expansion out into the solar system.