OSIRIS-REx and the Bennu Bounce

Back in December 2018 I wrote about the encounter between the NASA's probe OSIRIS-REx and the asteroid Bennu. After a lengthy journey from Earth, the probe had settled into orbit and was about to begin studying the asteroid.

Since then, we've learned a number of unexpected things.

First, there's water there. Not a lot, but it looks like water is turning up all over the solar system. But there may have been a lot more water there in the past, with evidence that it may have actually flowed through Bennu's interior.

Second, there's organic carbon there. Because carbon forms the backbone of all organic molecules such as sugars and alcohols, this might hold some clues to the origins of life.

Third, and the most interesting thing (for me, at least), was that Bennu is a remnant from a larger asteroid that had been blasted to bits in a collision. This gave Bennu not only its odd diamond shape, but also its relatively fast spin. That would have been quite a sight.

Our understanding of what went on in the solar system during its formation is only theoretical. Getting a good look at something that hasn't changed since then will show us more about the origins of our home.

So what happened next?

NASA selected a spot to... er "land" isn't quite the right word: it was more like a bounce. Four potential sites were selected, named rather nicely after birds. After some deliberation, the site chosen was the Nightingale crater.

The craft extended a pod, which touched the surface for just long enough to suck up some grit particles. They're not totally sure, but there might be up to two kilograms of regolith in there. It wasn't without dramas, though, a problem with the lid of their container means they lost a bit. There's sufficient there, though, safely tucked away.

Now, OSIRIS-REx will begin its long journey back to Earth.

Nightingale Crater has only "recently" been exposed - presumably in a meteorite collision. This freshness prompted Nightingale as the choice of landing site. Organic carbon breaks down over time when exposed to solar radiation, so Nightingale Crater was a good place to find material that scientists want to study.

The grit sample will show us more about Bennu's water, the organic carbon, and maybe about that past collision.

Images: NASA