This Saturday article thing is probably not going to continue being every week, no matter what the past three weeks might indicate. However, I did want to share this article I read in Science about an asteroid sample return mission to Ryugu, a C-type asteroid that is, as the saying goes, in the neighborhood, (by which we mean that at its closest approach, if the timing lined up for its orbital position and the Earth’s, it would be a mere 94,500 km away, but because of the phasing of and inclinations of the orbits it is almost always much farther away than that, averaging a distance from Earth of about one astronomical unit, or the distance between the Earth and the Sun).
I think we should take a moment to marvel over the phrase “asteroid sample return mission.” Until I was involved in real satellite projects, I didn’t fully internalize just how difficult such a mission paradigm really is. We can talk about lunar regolith collection and journeying to Mars all we want, but the truth is that sample returns from any celestial body are incredibly complex and difficult. The Perseverance Rover on Mars is collecting samples, but there is as yet no real plan to retrieve them and bring them back to Earth. Even Moon sample return missions are rare. That we can send a probe to an asteroid, even one relatively nearby, and return with any amount of material is simply incredible.
Plus, the team of Hayabusa2 came up with a wonderfully innovative way of collecting samples from a celestial body too unstable and without enough gravity to safely land upon: bouncing. This will make sense if you watch the videos associated with the article, which you really should. Even if you don’t read the full paper, you should at least download and watch the videos, which were taken by the spacecraft during its mission at Ryugu. That in and of itself is incredible, that we can download and view footage taken by a robotic space probe at an asteroid.
The paper is called “Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth,” and is a quite interesting read. Like I said, you should at least watch the videos, and don’t get bored before the fourth one, or you’ll miss some excitement. At least, I find it exciting. If you have any questions or thoughts, I’d love to talk about this mission and related topics further in the comments below.