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Arizona-Led Space Mission Arrives at Asteroid

NASA Goddard Space Flight Center

A NASA mission to an asteroid arrives at its destination today. OSIRIS REx is led by the University of Arizona and it’s the first U.S. spacecraft to visit an asteroid with plans to bring a sample of it back home. Scientists say the mission will tell us about the origins of the solar system and how to protect Earth from asteroid impacts. KNAU’s Melissa Sevigny spoke with deputy principal investigator Heather Enos.

How much do you expect to be able to bring back?  

Our requirement or expectation is that we will get a minimum of 60 grams of material, which doesn’t sound like very much, it’s like a good sized coffee cup. We do have the capability of collecting up to 2 kilograms. Being able to return it to Earth and putting into a lab analysis type of setting, there’s so much science that can be done with literally just a few grains of soil.

Why send a spacecraft to an asteroid? What’s so special about Bennu?

OSIRIS-REx is going to asteroid Bennu to retrieve a sample and return it. What makes Bennu so special is that it is a carbonaceous asteroid, and what that means is it’s expected to be a very pristine nature. It’s a time capsule of what happened as the solar system was forming. We believe it holds clues to the origins of our Mother Earth, and possibly it contains materials that are high in amino acids and carbon-rich material that give us a peek back into what really was happening during the formation of Earth and what may have brought life to Earth.

Bennu is one of those near-Earth asteroids that actually has a small chance of hitting Earth one day.

That is correct. Currently the estimate is we anticipate a 1 in 2700 chance of it hitting the Earth in about 150 or 160 years from now. Part of what we will be doing as one of our objectives is studying the behavior of the trajectory of Bennu. It really is a great opportunity for us to get some information to perhaps learn how to mitigate asteroids that may be in a collision path with the Earth.

Credit NASA/Goddard/University of Arizona
Asteroid Bennu, photographed by OSIRIS-REx

So if all goes well, we’ll soon be flooded with close up images of Bennu. What do you expect to see?

We already, during our approach, have begun to get some very great high resolution images. We have a camera system called OCAMS, which was—we are really proud—was built here at the University of Arizona. We can actually get images to the sub-millimeter level, so we will be able to see grain sizes, boulders, craters of the surface of Bennu. In addition we have some very powerful spectrometers also in our instrument suite. So we going to get a lot of information about Bennu while we’re at the asteroid that will inform us in terms of ultimately where we will go to the surface to collect our sample.  

What excites you the most about this mission?

The thing that excites me most about the OSIRIS REx mission is the fact that we are literally going to a world that we’ve never been to before. But on a personal level the thing that has brought me the most gratification in this mission, is it is a long mission—I’ve been working on it for 10 years, there’s another 4 or 5 years to go before we finish getting the sample and bringing it back to Earth—and I’ve had a great opportunity to start to transfer the knowledge that I have from working on previous missions to the next generation, and mentoring and teaching and watching their excitement has brought me a lot of self-gratification.

Heather Enos, great to talk to you today and good luck.

OK, thanks Melissa.

Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
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