Last week Hayabusa2, a Japanese asteroid sample return mission, dropped some mini rovers on asteroid Ryugu. After arriving to the asteroid a couple months ago, the mission dropped off the mini Minerva IIs to bounce around the asteroid and do some intel on where the big spacecraft should land. Although their sensors are tiny, these babies get a closer look at the asteroid. Their small measurements help inform mama Hayabusa2 what it has already seen (taken measurements of) to make sure it is a good understanding of the asteroid before it lands!
Artist’s interpretation of Minerva II rovers on asteroid Ryugu’s surface by JAXA
The Minervas themselves are able to hop around the asteroid by a simple wind up mechanism. They slowly wind up and then immediately brake causing them to pop off the ground. Also it is not too hard to pop off the ground of Ryugu since it only has 1/13000000000000 the amount of gravity of Earth. YEP you heard that right! Asteroids are so small so they don’t have as much gravity. If you were on Ryugu, you could run fast enough to put yourself in orbit, but don’t run too fast because you might escape the asteroid altogether!
Here is a video from one of the Minerva II rovers on the surface of Ryugu.
6. Rover-1Bが動画撮影に成功。2018年9月23日10時34分から11時48分（日本時間）まで15枚取得した画像による動画。 https://t.co/UOSvu33FwQ
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以上です。（スレッド投稿がうまく行かずバラバラに出し、失礼しました） pic.twitter.com/vQlSM0SYHc— 小惑星探査機「はやぶさ２」 (@haya2_jaxa) September 27, 2018
Artist rendition of Mascot communicating with Hayabusa2. Image provided by CNES
There is one more big event coming up for the mission. These little guys were actually a part of a dress rehearsal for a bigger instrument, Mascot. Now that JAXA knows a little more about the asteroids (the Minervas seem to be able to maneuver about the asteroid), their lander, Mascot, will descend on the surface of Ryugu on October 3rd and get even better measurements of the asteroid to send back to the mothership.
Why all the fuss? Well, asteroids are extremely tricky. Remember what I said about their gravity being so tiny? That means a lot of other effects (like the Sun’s light) make the orbit and descent harder to predict. Also, because asteroids have a small amount of gravity a lot of them are just piles of rubble. So JAXA wanted to make sure with the tiny rovers that they weren’t sending their lander into a pit for it to sink into but onto a sturdy part of the asteroid where it will be able to land and later the mothership will be able to land. Long story short, doing science in space is hard but especially with asteroids…. hence why the only landings humanity has had have been crash landings 😬
Keep your fingers crossed for Mascot!
I will leave y’all with this selfie shadow Hayabusa2 took on its way down to drop off the Minerva IIs.
Hayabusa2. Image provided by JAXA
As always, happy exploring!!!
