A space mission led by the University of Arizona will make a daring attempt tomorrow to scoop up some pebbles from an asteroid. The OSIRIS-REx spacecraft is more than two hundred million miles from Earth and it has to touch a spot on the asteroid Bennu the size of a couple of parking spaces. It’s the first U.S. attempt to an asteroid sample back to Earth for analysis. Scientists say it could answer some big questions. KNAU’s Melissa Sevigny spoke with the mission’s science team chief Mike Nolan.
Describe what you have to do tomorrow to scoop up a sample of this asteroid.
So currently the spacecraft is in orbit around Bennu. We’re going to very precisely time when it leaves orbit so it gets to be the sample site at the right time of day when the lighting is just right… When it touches the surface it has a cylinder of nitrogen, it looks like a small scuba tank cylinder, and it going to blow that gas on the surface of the Bennu which is going to scoop that material into the sample collector, which looks like an old fashioned car air filter… As soon as that’s happened—we’ll do that for five seconds, then it’s going to fire rockets, and head out away from Bennu.
The OSIRIS REX spacecraft has been orbiting Bennu for almost 2 year now. Can you tell me some of the things you've learned about it so far?
The weirdest thing was these particles being thrown off that. That was the thing that was totally not expected….that some process, probably having something to do with sunlight heating things up and cooling them off... is basically making these particles spew off once a week. That’s pretty odd. It is looking—and we had always hoped this—but it is looking like the rocks on the surface may be fragile enough that if one of them was thrown off and arrived at the Earth to fall it would probably burn up in the atmosphere rather than fall to make a meteorite… And so we’re thinking this might be a new material we’ve never actually seen before in meteorites. That’ll be very cool…. When we study what the solar system is made of, what the Earth formed from, what the Sun formed from, we use meteorites as our best evidence of what they would be, because they’re the least processed … If it turns out there are kinds of asteroids that aren’t making meteorites, because they can’t survive, that’s telling us—that may change some of the things we think about what the earth is formed from.
Tell me more about that. So why study asteroids like Bennu?
There are basically three reasons why you’d want to study asteroids beside pure curiosity. As I said, asteroids are believed to be the source of most of the material that made the Earth … and so what is the Earth made of, what did the solar system from? Another one is resources. If you ever want to go out into space and do things asteroids are your most easily accessible material… Water is hard to come by. And it’s looking like there is enough water on Bennu that it would be useful if you wanted to go get water. And the other one of course is potential hazards. Bennu isn’t big enough that if hit the Earth it would destroy civilization, but it would make a pretty big mess, and you wouldn’t want to be anywhere near where it was… So it’s one of the few natural disaster kinds of problems that we could actually do something about.
So if all goes well the sample will be back to Earth three years from now, what happens next and what do scientists hope to do with that material?
After it gets back? Fast-forward three years, the sample arrives back, it crashes into the desert in Utah, at a time that we know to within 10 seconds already. Then it goes to Johnson Space Center where it joins the Apollo rock collection. It’s going to be treated that same way. Three quarters of that will just be archived for the future. We’ll take a quarter of it, and then…people will propose to do more detailed experiments…. We’re forming hypothesis about what we’re going to find and measure and what we’ll do with it. I think it’s quite likely this is material we’ve never seen before. So we don’t know what we’ll find. We think it may very well be different from anything we’ve found before.
Mike Nolan, thank you so much for speaking with me.