ASU Professor explores role in NASA OSIRIS-REx probe

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Phil Christensen, Regent’s Professor at the ASU School of Earth And Space Exploration, sits down with Arizona Horizon host Ted Simons to discuss the NASA OSIRIS-REx probe, which will make a fly-by of the asteroid Bennu.

Ted Simons: Coming up next on Arizona "Horizon," a spacecraft flyby with a local connection. Also tonight, self-driving cars, virtual reality? What is next? A festival looks at the future of technology. And in our continuing series, Vietnam Arizona stories we hear about the building of the Vietnam wall in Arizona. Those stories next on Arizona "Horizon."

Arizona "Horizon" is made possible by the contributions from the friends of Arizona PBS. Thank you.

Good evening and welcome to Arizona "Horizon." The former Arizona governor was in Washington today for a discussion on the future of NAFTA and the state of U.S.-Mexico relations.

Janet Napolitano: I think our countries are generally much stronger when we think of ourselves as an economic region and we are working to facilitate lawful travel and trade. As I said before, the growth in trade has meant growth in jobs in the United States during the dependency of NAFTA. So to lose NAFTA would be to lose that economic benefit.

Ted Simons: She adds the rhetoric coming out of Washington that is blaming problems in the U.S. On Mexico is behind President Trump's plan to end DACA. She is suing the Trump administration to stop the suspending of DACA. Osiris-Rex is expected to flyby our area and it will give scientists a chance to test the probe. ASU scientists who created one of the instruments are among those taking part.

PKG: For most of my career, I have been studying mars. For the last 25 years, my team and I here at Arizona State University have gone building instruments to do just that. Our colleagues at the University of Arizona called and asked if we wanted to build an instrument for the Osiris-Rex mission to go and study the asteroid Bennu.

Greg Mehall: My name is Greg Mehall and I am the projector engineer of the thermal emission spectrometer tools. That is one of the tools aboard the spacecraft. Osiris-rex will study Bennu for a year. We launch in 2016, September. We get there about two years later. We study the asteroid for a year using the various instruments onboard. With those data, we select the optimal selection for the sample site. Once the sample site is selected we will do multiple maneuvers above that area to make sure the spacecraft and instruments are capable. It will descend to the surface, collect the sample and put it into a storage container and return it back to earth. The main object is to bring 60 grams of this asteroid back to earth because that sample scientists will use to study this.

Joining me now is Phil Christensen a professor at USU School of Earth and Exploration and the principle investigator for the thermal emotions spectrometer. Good to see you. The Osiris-Rex mission is to go up there and make contact with this asteroid, correct?

Phil Christensen: That is right. For years, NASA has been spending spacecraft out in the solar system and we study them but they are starting to have missions to bring samples back. We will go to this asteroid, collect some, bring it back, and study it in more detail.

Ted Simons: What was ASU’s involvement in the mission?

Phil Christensen: We have been building instruments for years and got good at it. We build what is called in infra-red thermal spectrometer. We map and say this part of Bennu is more interesting than that and pick what bits we will bring back home.

Ted Simons: It is called Bennu?

Phil Christensen: There was a contest and a young student picked that name.

Ted Simons: Why this asteroid?

Phil Christensen: It is very primitive. The solar system when it first formed there were very -- when it first formed and the sun formed you got these asteroids that have organic compounds. The stuff that makes up life on the earth. Those asteroids and compounds have been floating more or less unchanged for four and a half billion years since our solar system formed. We go back in time and sample this and get that primitive material and see what it was like. It is sort of like going back to the formation of the solar system to see where that organic stuff came from.

Ted Simons: How big is this asteroid?

Phil Christensen: It is about five football fields in size. It would fit on the ASU campus. But what it makes up in size it makes up in excitement.

Ted Simons: It has been this size for billions of years?

Phil Christensen: Not sure. Asteroids occasionally collide with each other. It might have been bigger and broken up into bits. It might have been smaller and accumulating and getting things sticking to it. But it has been roughly this size since the beginning.

Ted Simons: Now, I also understand, it is possible, maybe not likely, but possible this thing could run into earth.

Phil Christensen: Of all objects out there that we know of, this has the highest probability of hitting the earth. That probability is small. But it is going to hit the earth sometime in the next 10,000 years. So we are trying to narrow that down. Is it in the next 100? 500? 10,000? Part of what we are trying to do is figure out if an asteroid was going to hit the earth how would we deflect it? We are studying this one with the intent of what would we do if we knew it would hit in 10 years.

Ted Simons: The idea of deflecting this means you change the orbit. Are you changing a bunch of other stuff up there?

Phil Christensen: Hope not. The asteroids are small and don't have much gravity. If you move it a little bit yeah, it will affect the orbits of other asteroids but space is really big. Things are really far apart. It probably won't mess other things up.

Ted Simons: Tell that to the folks on the Yucatan peninsula. Compare this asteroid to the one there that wiped out life on earth.

Phil Christensen: This, if it hit, would make a hole in the ground about five miles in diameter which a big deal. In Yucatan, the hole was 80 miles in diameter and wiped out life on earth. That was bigger than this one. If this one hits it would be a mess but not as bad as the Yucatan one.

Ted Simons: And we would see it coming. It would not be like you wake up one morning and the newspapers say hey.

Phil Christensen: We will study its orbit precisely after Osiris-Rex we should see able to have a much better prediction of when it will hit. It is going to be a hundred years from now or something like that.

Ted Simons: And Osiris-Rex is coming back to the earth for a swing shot effect to get back out? When you see going on?

Phil Christensen: We fly out and we use the gravity of the earth to slingshot Osiris-Rex to get more speed and send it all the way out to Bennu. By doing that, when we have launched the spacecraft initially the rocket didn't have to be as big. We had a smaller rocket and used the earth to give it a boost.

Ted Simons: And that should be enough?

Phil Christensen: That is what the trajectory scientists say.

Ted Simons: You will be seeing how the spacecraft looks at earth to make sure it is looking at it properly?

Phil Christensen: Absolutely. This is our first chance since launching it a year ago to turn it on and look at something real. We will look back at the earth, get data, and make sure the instruments are working. It is also a dress rehearsal. We will use tomorrow's encounter to practice what we have going to do a year from now when we get to the real target. So it is kind of like a dress rehearsal.

Ted Simons: How close to the earth do we think this is going to get?

Phil Christensen: Something like 25,000 miles? Something like that? It is closer than the moon. So it comes –

Ted Simons: Interesting.

Phil Christensen: It is pretty close.

Ted Simons: Will amateur photographers be able to see this?

Phil Christensen: Yes, and the university of Arizona is running a program saying this is exactly where it is. There is a program that amateur astronomers are going to see.

Ted Simons: Can I stand in the backyard and point?

Phil Christensen: You need a telescope. It would be fun to see.

Ted Simons: It would be. But when will be the best time to view this?

Phil Christensen: So the closest approach is tomorrow morning about 9:00 in the morning. Unfortunately, for us that is daytime so it will be hard to see. But you know, it is going to take a couple days to completely get too far away from the earth that you will not be able to see it anymore.

Ted Simons: Between ASU’s involvement and U of A, Arizona's status of space exploration improving?

Phil Christensen: It is fantastic. You could argue Arizona has the strongest planetarium program between any state in the country. We are probably involved in a dozen NASA missions. It is phenomenal.

Ted Simons: Must be so excited for you. Good to have you. Technology festival in Tempe offers a look at the future. That is next.

Artificial intelligence, virtual reality and self-driving cars are no longer the stuff of science fiction. The technology is being here and some of it is being displayed at the phoenix emerging tech festival in Tempe. Here is the founder of the festival. Welcome to Arizona "Horizon."

Thank you.

Phil Christensen: Regent's Professor, ASU School of Earth And Space Exploration

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