Inside NASA’s Planetary Defense Office
There are thousands of asteroids and comets that orbit the sun, traveling in the same cosmic neighborhood as the Earth. But what happens if one of these space rocks gets too close for comfort? NASA’s Planetary Defense Officer Lindley Johnson and Near Earth Object Observation Program Manager Kelly Fast map out what celestial objects the team is keeping an eye on, and ideas for deflecting and keeping asteroids at bay.
Kelly Fast is Program Manager in the Near Earth Object Observations Program at NASA Headquarters in Washington, D.C..
Lindley Johnson is the Planetary Defense Officer in the Planetary Defense Coordination Office, based at NASA Headquarters in Washington, D.C.
IRA FLATOW: This is Science Friday. I’m Ira Flatow. A small asteroid is going to whiz by the earth next week. We don’t know exactly how close it’s going to come. It could be as far away as 3 million miles from the planet. There’s a slight chance it could come as close as 15,000 miles above the earth’s surface. But we do know that it’s one of the thousands of asteroids and comets circling the sun in the same cosmic neighborhood of our planet. And in 1908, a small meteorite exploded over a remote area in Russia, knocking down 80 million trees, flattening 2000 square kilometers of forest. It was Tunguska , remember that very, very, very famous event. And it was only due to luck, because it was so remote, that no one was hurt.
Well, after many years of just talking about finding threatening space objects, NASA is helping to search for these asteroids and comets that might do real damage. Kelly Fast is the manager of NASA’s Near Earth Object Observations program, and Lindley Johnson is NASA’s Planetary Defense Officer. They’re both based out of NASA’s headquarters. Let me send the question out to you. What are your ideas about how we might defend ourselves against incoming asteroids? Our number, 8-4-4-7-2-4-8-2-5-5. You can also tweet us @SciFri, S-C-I-F-R-I. Phone again, 8-4-4-7-2-4-8-2-5-5. Welcome to the program.
LINDLEY JOHNSON: Thank you Ira, this is Lindley.
KELLY FAST: Thank you, Kelly.
IRA FLATOW: Well, let’s first talk about the Planetary Defense Coordination. It sounds like a pretty big job. Tell us how– what are you coordinating?
LINDLEY JOHNSON: Well, Ira, actually NASA has been in this business for finding Near Earth Objects, asteroids and comets, for a little over 15 years now. We started the program in 1998. This is just formalizing our capabilities, and the purpose of the Planetary Defense Coordination office is oversight management of all NASA’s projects to find and characterize asteroids, as well as figure out what we might do about one if it were a threat to impact. Plus, we work across the U.S. Government agencies and with our international collaborators.
IRA FLATOW: Is there a big plan, internationally, to coordinate looking for these asteroids?
LINDLEY JOHNSON: Well, yes. We have been working within the form of the United Nations Committee on peaceful uses of outer space for several years, and with our other astronomers and space agencies in that committee, we’ve developed what is going to be a pattern for the international response to the asteroid hazard. We are working together in an international asteroid warning network. Territories around the world contributing observations to the Minor Planet Center. And then we also work with the space agencies in a forum called the Space Mission Planning Advisory Group, where we look at the technologies and techniques that could be implemented if we needed to divert an asteroid on an impact trajectory.
IRA FLATOW: Let’s get up to that in a few minutes, but I want to talk about Congress, which put $50 million into the 2016 budget to set up this Planetary Defense Coordination office. And that’s more than double the budget for tracking asteroids in 2012. What happened? I mean, I was thinking well, seen too many Bruce Willis movies? Finally taking it–
LINDLEY JOHNSON: As we learn more and more about this hazard, and it gets more and more folks up to speed on what the possibilities are that we could be impacted by something which could take us totally unaware unless we’re looking out for it, there’s been more interest and more support for the program at NASA. As I said, we’ve been doing this for some 15 years and the budget has increased a little bit almost every year in the last five or six years.
IRA FLATOW: Now Kelly, you monitor Near Earth Objects. What do we consider near?
KELLY FAST: Well, it would be asteroids or comets whose orbits bring them close to earth’s orbit. And so it might not be there at the same place at the same time, but we want to have an awareness of what is coming perhaps a little too close for comfort, in order to track them, keep track of them, just so that if there is something that is of concern, we can be aware of it. And just be aware of the whole population that’s out there. It even gives us a good science background for how things have evolved in the solar system. But it’s also very practical for, as one of our colleagues says, finding them before they find us.
IRA FLATOW: Well, you did find one. I mean, there is news that a small object is supposed to come by next week some time. And what I wonder about is every day I hear a different projection for this passing of a small asteroid. Some days it’s on a Tuesday, some days it’s on a Wednesday. It’s either 15,000 miles or three million miles. That’s kind of scary that you don’t know where it is.
LINDLEY JOHNSON: Oh, it’s not quite that variable. But yeah. You’re talking about 2013 TX68 is its designation. This was about a 30 meter asteroid that was found back in 2013. But we only got a couple of days of observations on it. And so the orbit that we can establish, based on those few observations, is somewhat uncertain. So that’s why there’s an uncertainty in the close approach distance to the Earth and exactly what day that close approach is. We know the orbit well enough that it’s not an impact threat to the earth, but it could come pretty close, if it’s out on the wings of that uncertainty curve.
KELLY FAST: But that object even isn’t unusual. This sort of thing is actually happening all the time, coming perhaps different distances past the earth. But there are close approaches made all the time by objects, but nothing that you know is of concern.
LINDLEY JOHNSON: In fact, in the last couple of days, we’ve had objects about that same size, 20 to 30 meters, that have come– we know– have come as close as the moon to the earth.
IRA FLATOW: But if you’re coming as close as 15,000 miles, you’re coming within the range of satellites that are up there, right? Could it take a satellite out as it’s coming through?
LINDLEY JOHNSON: Well, it’s improbable that this object is coming that close. Like I said, that’s way out on the wings of the uncertainty curve. It’s more likely that it is more than a million miles at that closest approach. But yeah, we do find these objects that are coming in close to the earth. Three or four times a year we will have a small object of a few meters in size that will come within the geosynchronous belt of satellites. And we provide that information to the Space Surveillance Network that is run by the Air Force for the Department of Defense, so that they can compare the trajectories of it to the satellite orbits to determine if there’s any probability of impact. But the chances of that happening are very, very slim.
IRA FLATOW: All right, all right. Let me give you a for instance. Let’s say you do find something that is heading toward the earth and might be a danger. You know, we see in the movies that they’re blowing these things up, but we know that’s the worst thing that you can do because now we’ve got a million of that stuff heading in our way. Is it possible to actually practice a technique with a safe asteroid and see if that technique will work or not? Nudging it out of the way, so to speak.
LINDLEY JOHNSON: Well, as Kelly says, one of the objectives of our office is to find any object that might be a threat, as early as we can, so that we have many years to determine what is the best cause of action to try and deflect it off its course. As I mentioned before, the Space Mission Planning Advisory Group, what we call the same page, the forum for space agencies to talk about what we might do, are investigating technologies and techniques, and working on mission concepts to demonstrate some of these techniques. For instance, one of the techniques is a kinetic impactor and NASA is in parallel studies with the European Space Agency to launch a mission that would have a collaborative effort. The ESA would send out the observation spacecraft, and NASA would launch the kinetic impactor, to demonstrate the kinetic impactor technique and deflect actually a moon of a small asteroid off its orbit, enlarge its orbit.
IRA FLATOW: How exactly would that kinetic impactor work? I mean, to the layperson, it sounds like you’re going to throw something at it.
KELLY FAST: Well, that’s it.
LINDLEY JOHNSON: Yeah, that’s the basic concept, What you need to do to make what would be an impact or a miss is just change its velocity by a slight amount. And if you do that enough years in advance, you only have to change that velocity by a few millimeters per second. And so you just slam a kinetic impactor into it at the right velocity vector. And that will impart the energy to either speed it up or slow it down, depending on which way you want to move it, enough so that a hit becomes a miss.
IRA FLATOW: Kelly, how do you determine what asteroid is the most threatening to earth? Is it based on an orbit, or in composition, or what?
KELLY FAST: Well, the Minor Planet Center collects observations from our asteroid survey assets telescopes on the ground, in space, and also from elsewhere. And the JPL Center for Near Earth Object Studies works with that information and comes up with a very precise orbit determinations, with some uncertainties, as we saw with 2013 TX68. That’s why we need as many observations as possible so that they can really refine those orbits. And they keep track of all that, and they continue to update orbits as we get more observations. And just by keeping that database and keeping track, they can model these objects and their orbits way out in the future, to see if something might present a hazard.
And so, it’s just a matter of collecting as many observations as possible, doing the orbit predictions with whatever uncertainties, whatever effects there might be that could change things, such as other planets tweaking things, or radiation from the sun. Coming out with their best orbit determination and then from that, assessing if something might present a hazard off in the future.
LINDLEY JOHNSON: Of our current catalog of almost 14,000 Near Earth Objects now, I think the highest probability of impact we have is for an object out in 2185, if I remember right, and it’s like a 1 in 498 chance of impacting the earth.
IRA FLATOW: But there was a meteorite over Russia in 2013. Remember that one, that a lot of people filmed? You didn’t see that one coming, did you?
LINDLEY JOHNSON: No, no, we didn’t see that one coming. Most of our survey telescopes are ground-based, and so therefore they can only observe at night. And this object came in the day time, out of the sun, but it was also a very small object, only a little less than 20 meters in size. And our systems really aren’t capable of finding objects that small, very far out in space. At best, we might see one coming inbound from the night side, maybe only a day or two before the impact.
IRA FLATOW: Let’s go to the phones. Let’s go to Alan in Brooklyn, New York. Hi, Alan.
CALLER: Thanks Ira. I’m just wondering, unless I’m wrong, I haven’t heard the same kind of opposition to investigating and spending money on this effort to stop an asteroid as we’ve had in Congress working against the threat of climate change. And if that’s correct, do you think part of the reason has to do with the contractors who benefit from the effort on asteroids who aren’t equally benefited any other way. And also, if we could ever get the kind of mobilization we need to fight asteroids, do you think that would change the perspective of people who’ve been opposing active work against climate change?
IRA FLATOW: Let me just remind everybody that I’m Ira Flatow. This is Science Friday from PRI, Public Radio International. Talking with Lindley Johnson and Kelly Fast of NASA, looking for objects in space that might hit us. Interesting question. Let me just reiterate. There’s not been this opposition to this kind of work in that Congress has given NASA money to this, as opposed to climate change research. Any–
LINDLEY JOHNSON: Well, Ira, I don’t think anybody’s getting rich off of this mission. The only $50 million a year of funding that NASA does on this, that’s spread across a number of survey projects and grants. There isn’t any major contractor involved in this at all. Most of our grants are to universities and space institutions.
IRA FLATOW: And it’s not just a NASA– not just a NASA project, right? We were talking about the European Space Agency is your coordinator. A bunch of different things.
LINDLEY JOHNSON: A whole bunch of different efforts, that’s correct. And I think the other thing about this is, this is something that’s fairly simple to explain to folks, that there are these objects out in space. We see them all the time. People see meteors all the time when they go out at night and look up at the sky. That’s just the small end of what we’re talking about. And there’s, in recent years with all the video cameras that people have, people are taking a lot of footage of these bolides. These are a little bit larger meteors that come into our atmosphere. So it’s, I think, something that people can really relate to and see that there is a threat here. And having a couple of Hollywood movies that entertain folks about it a little bit didn’t hurt.
IRA FLATOW: Kelly, are amateurs involved in this?
KELLY FAST: Yes, actually. Yes. Amateur astronomers also observe these objects. With smaller telescopes, they’re limited in how faint they can go with looking at Near Earth asteroids and comets, but they are contributing and they take observations and submit them to the Minor Planet Center. So yes, they’re involved also.
LINDLEY JOHNSON: They also do what we call a light curve analysis for us. They take, over the course of a night, take how bright the object is. And you see differences in the brightness of the object, and that’s an indication that it’s rotating. And so from that, they can determine what the rotation of the object is. And some cases, if it’s done right, you can actually start to build up a shape model of the object.
KELLY FAST: Just in general, you do want to– in addition to finding them and tracking them– you do want to understand more about them, how they’re shaped, what they’re made of. The professional observatories do spectroscopy to characterize these objects, to figure out what they made of. Are they more of rock, are they metallic? And that’s part of trying to get the big picture. So that also feeds into if there is some sort of mitigation activity, you know what to do, depending on what that object is made of and how large it is.
IRA FLATOW: Thank you both. Kelly Fast, manager of NASA’s Near Earth Object Observation program, and Lindley Johnson, NASA’s Planetary Defense Officer, both based at NASA’s headquarters.