Planetary Radio: Space Exploration, Astronomy and Science - Space Debris Can Ruin Your Day

Episode Date: March 2, 2009

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Space debris and satellite smackdowns, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. You heard the story. An Iridium satellite was minding its own business when it had a close encounter of the fourth kind with an old Soviet bird, Kablooey. We'll talk with space debris and planetary protection expert Bill Ehler about the increasingly crowded space above our planet and the threat all that junk poses. Bill Nye is back to tie together

the importance of science education and the launch of the most powerful tool yet for discovery of extrasolar planets. And Bruce Betts will help me ponder birthday presents in this week's What's Up segment. A classic Q&A too. Here's Bill. Hey, Bill Nye, the planetary guy here, Vice President of Planetary Society. And this Thursday, the 5th of March, I will be testifying before Congress. Well, okay, I exaggerate. Before the House Appropriations Committee that affects, of all things, prisons and space exploration. And I'm going to talk about science education and the importance of the United States to remain the world leader in science by encouraging very young people to start pursuing science when they're in elementary school, junior high school, high school. That

stuff, if I may, a broken record from the science guy, a skipping CD from the science guy. Anyway, during that talk, rest assured, I will mention the Kepler mission, which is to launch that night. Now, Kepler, as you may recall, was Tycho Brahe's buddy, his understudy, and he helped Tycho Brahe map the heavens in the first way, and then he developed the three things we like to call Kepler's laws. Well, we're going to use the Kepler telescope, traveling in the Earth's orbit, looking off into the distance of the Milky Way galaxy to find planets that are like the Earth. This is part of the terrestrial planet finding program at NASA. And the idea is it has this crazy telescope that will spin every three months and then keep the radiators radiating,

keep it very cold, keep the solar panels generating solar power. And for three and a half years, look into this part of the sky, hoping to find a planet that might be a 30th the size of Jupiter, could even be 600th of the size of Jupiter. Man, if we can find that, if we can find evidence of a terrestrial and Earth-like planet, oh my goodness, that is a reason to celebrate science. That is a reason to celebrate science education. So I don't know, maybe I'll be on C-SPAN on Thursday, but whatever's going on, I will be fighting the good fight to try to encourage our representatives in Congress to fund science education so that the United States can be a leader in space exploration. To those listeners

who are not in the United States, keep up the good work. Let's explore space and, dare I say it, change the world. Well, thanks for listening. I've got planetary guy. There's a great shot in the movie WALL-E that shows our planet surrounded by all manner of orbiting garbage and burned out spacecraft. Bill Ehler knows that image is not far off from the truth. Bill joined the Aerospace Corporation in 1974. He's still with that Southern California aerospace contractor, directing its Center for Orbital and Reentry Debris Studies. Bill has served as an on-camera expert for many news operations,

sharing his deep knowledge of the threat posed by hundreds of thousands of individual pieces of space junk. The danger is not just to satellites and spacecraft carrying humans. It extends to all of us down here on Terra Firma. Bill, thanks very much for joining us on Planetary Radio. I am hoping that you're not going to tell me that the danger of running into somebody's runaway wrench or another piece of space debris is not, at least not yet, right up there with protecting yourself from vacuum and radiation in Earth orbit. Oh, no. The risk is still pretty small that at least one of the larger objects will strike another one. So that's a very fortunate thing. And yet there is demonstrable evidence that this can be a rather catastrophic problem,

and we only have to look to the story that was in the news just a few weeks ago, this collision between an active Iridium satellite and apparently an old Soviet thought to be dead and maybe reentered satellite. Now, I know you haven't really studied that case, but were you surprised to see that in the headlines? You haven't really studied that case, but were you surprised to see that in the headlines? Not really. I think that those of us who are in the business of looking for collisions or in the space debris business actually expect that these are the kinds of things that we'll begin to see more of, simply because we're putting more objects into space, and we have a lot of objects that are debris at the present time.

How much stuff is currently up there that we even know about? Well, we currently track around 18,000 objects. These are objects that are larger than a softball, more or less. So we know about those, and then we also know that there are a number of smaller particles that we don't track, and there are hundreds of thousands of those. So if you look at the ones that actually could be harmful to a spacecraft, anything larger than, say, a pencil eraser can be a real problem, and there are probably several hundred thousand of those.

The other story that I can remember was the object, apparently one of these very small ones that could not be tracked, that once struck one of the space shuttle's windshields. Oh, yes. That's a fairly famous picture. It was a very small fleck of white paint that struck a space shuttle windshield and actually caused a little pit in the glass. shield and actually caused a little pit in the glass. And so even these very small fragments, when they strike an object, they are moving so fast that they can cause damage. And interestingly, it's not all that uncommon to have windows replaced from the space shuttle for exactly that reason.

Nice proof of Newton's laws of motion, if nothing else positive is to come out of this. I'm sure that you have had far more than I've had, and even I've had a couple of people ask, well, why don't we just go up there and sweep all this stuff up? That's kind of a big challenge, isn't it? It really is a challenge, and if you think about the amount of effort that we put into putting something into space, if we were trying to bring down, say, a larger object, doing that would basically be a similar effort.

And so that is really one of the problems. And then, in theory at least, you could go up and rendezvous with a larger object, either put a little rocket motor on it or grapple it and move it to someplace or reenter it. But that requires a fair amount of energy and would be an expensive thing to do. You've also demonstrated through the work of your center that the danger is not just to other objects in orbit, but to those of us here down on the ground. Yes, that's one of the things that we've been looking at for a number of years has been what happens when something like a man-made object reenters the atmosphere.

A lot of people think these things just burn up. Unfortunately, that's not necessarily true. We believe that sort of a rule of thumb says that anywhere from 10 to 40 percent of the dry mass of an object that's reentering the atmosphere will survive and hit the ground. So let's talk about solutions that are available to us. First of all, about what we can do about the stuff that's already up there. Well, you know, that's an interesting one. And this is an area where someone may have some creative solution that actually could help us with this problem.

And there are basically two of them. One is what do we do about the larger objects? People have been considering the geosynchronous orbit, which is where most of our communication satellites sit, and weather observation satellites and things. The advantage is that most of the objects up there are traveling in the same direction, which is a help. And in theory, you could put something up there to deal with the debris in that regime. Again, it's very expensive to get that high,

but in theory you could put something like a space tug up, which would grapple an object and move it. You could do something similar in a low-Earth orbit, although it gets a little harder down there because these orbits are inclined at different angles, and that can make it a little bit more difficult to get to some. And then the real challenge is with the small debris, the things that we don't see. These things, as you said, if they strike a windshield or hit an instrument, they can basically do serious damage.

There's a lot of that stuff around, and we'd like to get rid of that. And getting rid of that is not an easy task. So it would be an area where there may be some creative solutions available. Your center has, in fact, developed some tools that are designed to help satellite operators, military or commercial, I suppose, get the heck out of the way if something has a shot at impacting. That's right. We and others in the community have been working on tools to actually predict when collisions will occur. on tools to actually predict when collisions will occur.

And if satellite owners have enough warning, they can move a maneuverable spacecraft out of the way. So these have been under development for, I'd say, on the order of 10 years or so and are certainly there. So that does deal with a part of the problem. There's a very nice image from this software that I think you're sent to develop, Collision Vision. Collision Vision, yes. Yeah, there's a nice model, image of a model that was generated that is on a website at the Aerospace Corporation, and we will refer people to that from our website, planetary.org slash radio, where we always put relevant links

relevant to the current show. I'll be right back with Bill Ehler of the Aerospace Corporation. This is Planetary Radio. Hey, hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President.

And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails, discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe. Here's how to find out more.

You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. Welcome back to Planetary Radio. I'm Matt Kaplan. Our topic is space debris and the havoc it can cause above our Earth and sometimes down here on the surface. Bill Ehler directs the Aerospace Corporation's Center for Orbital and Reentry Debris Studies.

He is also about to hold an international conference about much more destructive collisions, the kind that could end life on this planet. We'll get to that in a few minutes, but first, more about when satellites collide. Here's one that it didn't even occur to me to ask until a moment or two ago. Have you considered collisions between satellites in a typical equatorial orbit and ones in a polar orbit? Well, sure, you can do that. I don't recall that image precisely,

but the issue with predicting a satellite collision is how good the data is, basically. Many people think that, well, we know exactly where these satellites are, and unfortunately that's not the case. There are errors associated with predicting where a satellite is going to be in the future. Typically the way to think about this is you basically will look at an object with a radar or an optical device and you'll say, aha, I know more or less where that is. And the more or less is because there are errors in my radar and my optical. You can only resolve it so well. And so there's some small errors in those measurements. And then as that

object is predicted to go forward in time, there are errors in the models that actually predict where it will be. And those errors are due to things like gravitational effects, sun-moon effects, the atmosphere in similar Earth orbit things. And so you don't know precisely where the object is going to be in the future. That makes it really difficult then to predict the likelihood that something is going to hit another object. And so you have to have some methods that will actually combine the errors for both the object that's your threatening object and yourself to be able to estimate if this object is going to hit you. And it takes a lot of work to do that.

What it made me think of are those landing ellipses that we see before something touches down someplace, let's say, like Mars. They can't say precisely, at least not yet, but they're pretty sure it's going to be within that space. That's exactly right. There's some errors associated with the models. You don't know exactly what the atmosphere is going to do to you. And when you do a little rocket motor burn, there will be some errors associated with that. So handling these errors in a systematic way or estimating when a collision will occur is something that's been a fair amount of work on.

What else should we be doing to prevent this problem from getting even worse? Well, I think maybe one of the easiest things to do is to not create so much debris. And the spacefaring community has been working in that area for several years now, and basically to stop or prevent explosions when satellites are left in orbit. For example, if you vent the propellant tanks and basically discharge batteries and get rid of energy sources that might cause an explosion when a satellite reaches end of life, that will reduce the chance that you'll create debris from an explosion. The other thing which is kind of interesting is back when I started this business 30-some years ago, it was not uncommon to have devices which separated stages by using exploding bands.

And these exploding bands were metallic bands. And so you'd basically have a little explosion that would go off, and you'd send off these metallic bands. And so you'd basically have a little explosion that would go off and you'd send off these metallic fragments. And we would worry about those fragments hitting, coming back and hitting the spacecraft that we were concerned about. But we really weren't concerned about the long term. And unfortunately, the long term is important. And what we're doing now is using separation techniques which don't create debris. So there's some design things you can do that just stop the creation of debris, and that's really moving quite nicely in the international community these days. Tell me a little bit about the conference that you have coming up in Spain. Yes.

If you want to think of Earth as an object you're trying to protect from collisions, we actually have asteroids and comets that we know have struck Earth in the past, and we have a conference in Spain on the 27th through the 30th of April of this year dealing with planetary defense, defending Earth from asteroids and comets. That should be a very interesting one that we'll be looking at all the way from what do we know about asteroids and comets, what's the latest information on that, and deflection techniques might we use, how would you design a deflection mission, and what are some of the political and policy issues associated with making the decision to act.

There's some very interesting topics in there, and we have experts from all over the world coming to it. This is not the first of these that you've coordinated, is it? No, this is the third, and we've had two conferences in the United States. This one is in Granada, Spain. The objective is to treat this as we believe it is. It's a worldwide issue, and this brings together the space-faring nations from across the world to look at what we know about this topic. And full disclosure here, I should mention that the Planetary Society has a role, I think a small one, in this conference, which is now less than two months away. What is your sense? You've been in this field for a very long time. Do you see this issue

beginning to get the kind of attention that you've hoped it would for a long time? Yes. Back when we started in 2004, there was a giggle factor that we worried about. That was that people, when you bring this issue up, would say, ha, that's never going to happen. We don't have to worry about that for a million years. And just in this relatively short amount of time, I think people have come to realize that this is an issue that humanity needs to consider. These types of disasters can be greater than anything we've ever experienced, and we actually have the technology now to do something about it.

So we can protect ourselves, but we need to be looking for these things, and we need to have some techniques available to do that. So I think that there's a lot more interest in it now. I'm really happy that we're seeing students interested in it, and that's very good, too. So I'm hoping this is going to move forward and we'll have some capabilities available. Bill, have a great conference in April, and thank you both for appearing on the show and for helping to protect our planet and the stuff that we send out there beyond our planet. Oh, thank you. Bill Ehler is with the Aerospace Corporation.

He joined them in 1974 and has been spending a lot of years protecting us from debris and other objects which may circle or may simply come closer to our planet than would make a lot of us comfortable. As you know, that's been a major concern of the Planetary Society also for many years now. He is the director of the Center for Orbital and Reentry Debris Studies at Aerospace. That's the Aerospace Corporation, of course. Emily is up next.

She's a bit under the weather, so here's a Q&A classic edition. Bruce Betts and this week's What's Up segment are just a couple of minutes away. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, Mars has a lot of things that look like dry river valleys, but they don't have any tributaries. Are these river valleys or are they something else? Like so many landforms on Mars, large channels are both familiar and alien. Like rivers on Earth, Mars valleys wind back and forth in sinuous channels. They travel from high ground to low ground,

which usually means they flow from Mars' southern highlands to the northern lowlands. They sometimes split into multiple channels, and they may contain streamlined islands. Although some researchers have proposed that wind or lava once flowed through those channels, most agree that water is the most likely fluid. But if you were to take a walk up

one of these ancient Martian riverbeds, you'd notice some things that were very strange. Unlike earth rivers, they usually have no or very few tributaries. No tributaries also means that they have nearly the same width along their entire length, which may reach hundreds of kilometers. The one place you sometimes find tributaries is near a channel's source. But even these are strange. They tend to be short and stubby, with round heads,

instead of branching into smaller and smaller streams. Taken together, many of the features of Mars' channels suggest that they did not form by an Earth-like water cycle, where water falls from the sky, flows across the surface, collects in lakes and oceans, and evaporates to start over. Instead, it seems that Mars's large channels originated from below, from groundwater pouring out onto the surface. Groundwater springs wouldn't need a very much warmer, wetter Mars. Liquid water is stable deep underground on Mars even today. Got a question about the universe?

Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up on Planetary Radio. Bruce Betts is the Director of Projects for the Planetary Society. He's going to tell us about the night sky. And hey, you are famous. You didn't tip me off. I just happened to hear by accident your appearance on NPR talking about the life experiment.

Yeah, I'm sorry I didn't tip you off. That was rude of me, but I thought you might listen and just get that certain thrill. I did indeed, since I'm a regular listener to that program. In fact, I hear that show more often than I hear this show Oh that's because they're daily and we're weekly

That's it I knew there was something like that behind it Yes no they talked to me about the Phobos life experiment The living interplanetary flight experiment Where Planetary Society is planning on sending microbes and other groovy organisms Out to Mars, Moon, Phobos, and back to test one more piece of whether life can travel between the planets. Panspermic. Exactly.

You can learn more on our website, planetary.org, if you're interested in finding out more about the experiment. And I'm sure we'll have shows on this very show to give you more information as launch approaches in the fall. Yeah, I'm looking forward to that. All right, tell us about other stuff in the night sky. For the next very few weeks, we've still got Venus as the star of the evening sky. Get it? Star, evening sky. Yeah, anyway, it looks like a really bright star over in the west after sunset. And then also rising around sunset now is Saturn, like a dimmer but still kind of bright star. Through a telescope, you can check out the rings. They're pretty well edge-on or close to it right at the moment.

You'll need binoculars or possibly a telescope, but there's a comet out there, Comet Lulin. It is kind of greenish in color. It's seen in the evening sky. It's between Leo and Cancer, moving rapidly, so check an online sky chart. It's comet Lulin, L-U-L-I-N, and it was actually discovered by one of our Shoemaker Neo Near-Earth Object grant winners using equipment that he got with our grant, and it's a fascinating story. He's now a 19-year-old college student in mainland China using an observatory, the Luneland Observatory, in Taiwan in a collaborative effort. Lovely story. Thank you. In the pre-dawn, we've got all that wacky planetary happening

happening. If you check out the east before dawn, Jupiter is getting pretty easy to see, the very bright star-like object. Down below Jupiter, still kind of tough, need a clear view to the horizon, but you might get a shot at Mercury, which is the brighter object, but not as bright as Jupiter. And then the dimmer reddish object, Mars. And Mars will keep getting higher over the coming weeks, as will Jupiter. Venus is, I'm sorry, Mercury is going to drop back below the horizon over the coming days and weeks.

So it's a busy, active, whole lot of festive stuff going on in the sky. I just realized I should have said warm and fuzzy comet, but that really wouldn't be appropriate for a comet, would it? No, they're cold and fuzzy, though. Yeah. Yeah, 50%, right? It'll have to do. On to random space fact. Done with great gravity.

Oh, gosh, I wish I had a gravity-based space fact right now. But what I do have is my periodic journey into the never-ending quest to give a feel for the scale of the universe. Or in this case, our little neck of the woods. Because, you know, it's really big and really empty. So here, are you ready for this, Matt? Yeah. If the sun were located in Los Angeles or Pasadena or Long Beach, you know, Southern California. The sun's located in Los Angeles.

And you put pluto because i still like pluto so we're going to put pluto in new york city then what would happen on this scale model well the earth would still amazingly be located in the metropolitan area of los angeles about 100 kilometers away roughly san bernardino for those who know the area. The sun would be 930 meters, or almost a kilometer in diameter. Earth would be a pesky 8.5 meters in diameter, out there in San Bernardino. Couldn't even see it.

But here you go, if you want to just take that next step to the closest star system, Alpha Centauri. Our scale model just blows apart because you have to go a third of the way to the real Mars, is where you would put Alpha Centauri on that scale. Oh, that's great. I thought it was going to be like the moon twice as far as the moon or something like that.

And I should have known better. 27 million kilometers away on this scale. Wow. You know, I'm a sucker for these, of course. You know that. That's why I keep feeding them out there, and I'm obsessed with them. Shall we go on to the trivia contest? We asked you last time around a simple question.

Hey, how old's the universe? How'd we do, Matt? Well, and I gave people some pretty good leeway when I put the question on the website. I said, give or take a billion years. Well, you were way too nice. I was. I was. The error bars are only around 100 million years.

And that's exactly what most people came up with. While a lot of people asked if we got anybody who said 6,000 years, not one person submitted that as their answer. So proud of all of you. Here is the one that came from Chet Twarog. Chet Twarog, first-time winner out of Hudson, Massachusetts. He said 13.7 billion years, plus or minus, he said 0.2, I think it's actually 0.1 billion years, or 100 million years, as you said. But dead on, Chet, so congratulations. We are going to send you a 2009 year in space calendar.

And if you want it, a rewards card from oceanside photo and telescope very cool yes this was uh nailed down by various measurements that all give a similar age but then it was really narrowed by the wilkinson microwave anisotropy probe a lot of people mentioned that uh by the way ed Ed Lupin pointed out that not only is the universe about 13.7 billion years old, but its birthday is next month, which is why there's such a run on birthday candles. Wow. Now, do you put a candle for every billion years? Every year? I think that's, he left that open, but I think he said that it's a very good time to buy stock in birthday candle companies.

I guess so. You know, I had no idea it was next month. I feel badly. But I bet that is in the year and space calendar. And what do you get? The universe. I mean, it's already got everything. Ooh.

Man, that should be the trivia contest, but I don't know how we judge it. Well, give us a new one anyway. All right, I'll give you something more mundane. When, when, when was the first main belt asteroid discovered? When was the first main belt asteroid discovered? Go to planetary.org slash radio, find out how to get us your answer. You need to get that contest entry into us by 2 p.m. on Monday, March 9th, 2 p.m.m. on Monday, March 9th. 2 p.m. Pacific time on Monday, March 9th. Okay, we're out of here.

All right, everybody. Go out there, look up in the night sky, and think about cold vegetables. Thank you, and good night. He's Bruce Betts, the director of projects for the Planetary Society. He knows what I leave on my plate at the end of dinner, and he joins us every week here for What's Up. Staying in bed for NASA and space exploration. That's next time on Planetary Radio, which is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.