Ep. 82: Space Junk

Fraser Cain: Space Junk! I love the sound of that. We didn’t get a lot of responses from high school students last week. I don’t know how many we got but we need more.
Dr. Pamela Gay: We in fact have heard no high school teachers or students asking to participate in our student questions show. Please participate. We want you. We want to help you.
Fraser: How can this be so hard? What is it going to take?
Pamela: We’ll send you buttons.
Fraser: Do we have to go on the road, take our telescope, or go from class to class?
Pamela: And we would if we had the money for that but we don’t.
Fraser: That’s true. So, don’t be afraid if you are in high school….
Pamela: Well, we get e-mails from people who are in high school. They just don’t want to participate in the questions shows.
Fraser: Even if you just e-mail us and say “I’m in high school”. We’ll try and take it from there.
Pamela: Give us your teacher’s e-mail or phone number and we’ll do the legwork.
Fraser: All right, let’s move on then. This week we are polluting every corner of our own planet so it only makes sense that we are going to take our trashy habits out into Space with us.
This week we look at the myriad ways we’re messing up Space. From the trash orbiting the planet to the radiation we’re leaking out into Space.
How bad is our trash problem in Space?
Pamela: Well, we’ve actually started flinging things outside of the Solar System. Light, objects, probably organics. We have probably sent biological materials out of our Solar System at this point.
Fraser: Okay, let’s classify this then. What exactly is Space Junk?
Pamela: Space Junk we typically think of as the golf ball that was hit on the moon; the zip-lock Baggies of random junk that have been hurled out of the space station; as dead satellites orbiting around.
Think of things that we have flung out into Space and no longer quite know where they’re heading because we lost communications with them. That’s junk.
Fraser: I find it pretty amazing that if it costs 10,000 dollars per pound to launch something into orbit (I haven’t done the metric calculation there) that people would lose track of it.
Like a satellite or a spent booster might have cost several million dollars to put it up into orbit and then just lose it. We don’t where it is.
Pamela: The boosters are just packaging. It gets hurled out into Space and does what it does. But, yes we’ve left airbags marooned on the surface of Mars from when the rovers landed and bounced all over the placed.
We have occasionally misplaced Space missions where we’ve sent something to Mercury or Venus and it didn’t work and we lost communications with it part way.
Sometimes we’re not quite sure what orbit these things are in after we lost contact with them. So, we just lose them.
Fraser: Right, that makes sense that we’re expecting them to be in a very specific orbit and we’ve got our dishes pointed where they should be and they go missing.
Because we don’t have dishes pointed at every possible orbit it’s out there somewhere trying to communicate and we’re not hearing the message.
Pamela: Then there are the things that we’ve put places and we know they’re going to die there.
With deep impact we’ve basically sent something the size and mass of a refrigerator hurling into a comet and that comet is still out there, still plugging its way around the Solar System now carrying a piece of Earth metal.
Fraser: What is the scale of the problem? Let’s talk about the stuff orbiting the Earth because I think that’s the largest amount. How big is the problem?
Pamela: I’m not sure anyone really knows. There’s this problem where you lose a bolt, you can’t see that from Earth. The Chinese launch a satellite that’s stealthy. We may not know where it is.
But there are hundreds of satellites out there that aren’t quite working anymore and they’re just hanging out in Space. Most of them eventually fall down.
But sometimes we boost things out into higher orbits that they just hang out up there forever. That’s one of the things we’re talking about doing with the Hubble Space Telescope is boosting it into a high enough orbit that it just stays up there.
Fraser: I guess that’s the other part of the puzzle is that in Earth’s orbit material that gets launched into orbit depending on the height of it’s orbit, it may crash back through the atmosphere.
What’s the process there?
Pamela: If you have something that is small and comes in at just the right angle as it hits the atmosphere it ends up ionizing and you wind up with random atoms of stuff in the atmosphere.
It also disintegrates, burns up so the entire craft is like you’re throwing it into the garbage incinerator in your basement. The atmosphere creates ash and we usually don’t ever notice those pieces.
They become part of acid rain or whatever. Or it just stays high enough up in the atmosphere that we don’t notice.
If you’re unlucky (and there is recently a legal case in the Soviet Union about this), and something is coming in for a landing near you, chunks may break off and almost hit your outhouse as what happened in Russia.
Chunks do make it through to the surface and then we pollute our own planet.
Then we’ve also over the years flung things at the moon and other planets and they’ve stayed there. So we’re gradually spreading metal bits about the Solar System.
In the case of Voyager I and Voyager II, we’re sending them outside of our Solar System.
Fraser: I’ve got some stats. U.S. Strategic Command maintains a catalog of about 13,000 objects that they are tracking. Some of those are just regular satellites and a lot of that is just debris.
There are some estimates that there are more than 600,000 objects larger than one centimeter in orbit around the earth.
Pamela: These are parts of solar panels that have broken off. These are tools that Astronauts have let go of. These are zip-lock bags filled with garbage that have been flung out of space stations. These are satellites that have been blown up by the Chinese or the Americans. These are all sorts of different objects.
This is a complex issue on many different levels. First off on the greedy basis, our planet has a limited number of resources. There is only so much metal on our planet that can be mined and turned into skyscrapers, computers, or satellites. We’re taking some of those resources and just abandoning them off of our planet.
Fraser: Well, it’s not much though.
Pamela: It’s still something.
Fraser: I wonder if it outpaces the amount of iron meteorites that are raining down from space.
Pamela: I think that is one of those things where currently yes, we are sending more metal into Space than Space is sending back down at the surface of the planet that we get to find and keep.
Fraser: I guess we’ll eventually be mining the asteroids. At some point it will turn back into a net game. Can you give me an idea of how long things last? Like if you launch something into a very low orbit, how long will it last in orbit? And then further all the way up to say geosynchronous orbit.
Pamela: I’m actually going to go the opposite direction. In a geosynchronous orbit, you’re so high up above the atmosphere that there’s basically no drag on you. So you just stay there.
Geosynchronous is a nice, friendly, drag-free zone to hang out in. This is where we put a lot of our weather satellites, our communication satellites. Objects that are in geosynchronous orbit are in orbit straight up from the Equator and they orbit the earth every twenty-four hours so as the Earth rotates, the satellite stays over the exact same point on the Earth continuously.
As you get to lower and lower altitudes, you start encountering the upper level of the atmosphere. It may only be a few particles per cubic meter but these particles hitting your spacecraft are, as you get to higher and higher densities is going to slow you down.
So, you can get to the point that something that’s right around 270-280 miles up is going to be able to deteriorate very quickly. You might have it where if it is not corrected every few months it falls out of orbit.
Fraser: That’s like the Space Station right?
Pamela: The Space Station is only about 300 miles up and they have to make constant corrections. It’s actually one of the concerns where when the space shuttle is attached it helps do some steering. When the cargo craft are attached they help do some steering.
A lot of different things are needed to keep the Space Station’s solar panels aligned with the sun and also just to keep it in a stable orbit. Skylab fell out of the sky.
Fraser: What plans then are there in place to try to deal with that? With the 600,00 objects that might be up there already how, do mission planners deal with this?
Pamela: Luckily Space is a big place. It’s sort of like saying there’s a thousand bolts scattered out over a football field. In general, if you’re running across the field in cleats, you don’t have to worry about getting a bolt stuck on the cleat. But they’re there and you have to worry about them because if you run around long enough you’re eventually going to trip over one.
There’s a lot of space junk up there. In general, it’s spread out; orbit’s a big place and you don’t hit stuff on a regular basis. But the space shuttle has taken dings from hitting small bits of stuff.
It’s possible as we increase the number of communication satellites, weather satellites, of all these things that            we consider necessary for day-to-day communications that we’re going to have to worry about a satellite that is on a polar orbit to map the planet where the satellite goes over the North Pole, the South Pole, round and round and round is coming around and collides face first into a satellite that is going over the Equator in an equatorial orbit.
So mission planners have to build three-dimensional models of where everything is going. They have to constantly update these models for the effects of drag and solar radiation. One’s orbit could be changed if it is hit by a micrometeorite.
All these things have to be constantly monitored and updated. There are actually people out there who do this in a sense for fun on their own. They go out with ham radios and listen to atomic clocks, getting a read out on when the time is and then report on their ham radios.
“Hey I see satellite X going straight overhead next to Star Foo”, and then the next person downrange makes the same announcement. You can actually listen to ham radio operators handing off satellites from one viewer to the next in some ways, which is kinda cool.
They keep track of the orbits of things that Joe Public isn’t generally supposed to know the orbit about.
Fraser: And I do a couple of stories a year on Universe Today where people working with the Space Station order it to fire it’s thrusters to move it out of the way of a possible impact trajectory from some piece of space junk.
So if there is something that is going to come within a couple of kilometers of the Space Station they will shift its orbit just to be safe.
Pamela: Because there is so much stuff out there and we’re never 100 percent sure of an orbit, it’s problematic. We do have to constantly update things.
We do have to shift things around and that’s what makes it so dangerous when we lose all sorts of control mechanisms on the satellites.
Satellites are kept in orbit using a number of different things. You have gyroscopes that help you keep track of what your orientation is relative to the stars.
You have thrusters that help align you to keep your solar panels in line with the sun. If you lose the thrusters or gyroscopes or worse you lose all of them, that becomes a satellite we can’t control anymore and it’s dangerous.
Fraser: So what do you see as the future for this? We’re launching more and more stuff into orbit every year. Is this getting to be a point where it becomes very dangerous?
Pamela: Periodically there have been different people talking about building little robotic satellites that go around and grab things; little garbage disposal units.
NASA used to have one that they showed at the Huntsville Marshall Space Flight Center and it was a donut looking thing. The idea was it would go around and grab satellites, change their orbits, bring them back to the space shuttle, all sorts of cool little garbage disposal device things.
Fraser: That sounds expensive.
Pamela: It sounds expensive but it’s cheaper to have something like that than for instance you have a satellite that is not working but is repairable but you don’t have a way to grab it and so you shoot it apart.
With a little grabber like this, you could conceivably go out, grab a satellite that’s a little bit wonky, tow it back to the space station, fix it up and then throw it back out and let it orbit again.
Fraser: But wouldn’t that only be for satellites that are in relatively the same orbit as the International Space Station? And that’s just a fraction of the junk that’s out there. Most of it is going to be incompletely different orbits.
Wouldn’t you have to launch a unique grabber just for the orbit of the device that you’re trying to capture? I mean with the amount of energies involved, it would be so hard to shift from one orbit to a completely different orbit.
Pamela: Only if you’re trying to do it quickly. If you’re patient, you can adjust orbits without expending a lot of fuel.
You can use ion drives or lots of different slow acceleration techniques and you can grab things from higher orbits and take them down.
You can grab things from lower orbits and take them back up. The biggest constraint is how much fuel is needed. But it takes less fuel to move something around in orbit than to move something from the surface of the planet to orbit.
Fraser: Well I still think that with the 600,000 objects already up there on completely different orbits, in many cases going maybe even in opposite directions or polar orbit versus equatorial orbit.
Pamela: Yeah it starts to be a tedious job.
Fraser: Yeah tedious is not the word I would go for. Insane might be more apt. I’ve heard ideas of people using lasers. How would that work?
Pamela: Well, laser is light and light can exert a force. This is how stars support themselves and so you can bump things’ orbit by hitting them with a laser. That’s one way to get them out of the way.
In general, you’re not going to blow things up with the laser. People want to blow things up with lasers, but in general the beams spread out too much, it’s just not going to happen.
But you could conceivably move things around. You could get them into a higher orbit where they’re not as dangerous. Or, if you knock them just right, you can knock them so that they hit the atmosphere and burn up in the atmosphere, problem solved. Object gone.
So, changing orbits is one of the keys either bump something high enough so that it’s out or harms way or bump something so that it goes into a lower orbit and again out of harms way.
Fraser: Now, I’ve heard of a one terrifying future possibility where you could get to the point where space junk is so dense and that the objects are colliding and you get this chain reaction.
One object gets smashed up, smashes into other objects and eventually you have this shrieking hail of metal surrounding the Earth, acting almost like a shield that would stop us from launching any new spacecraft outside the planet.
Is this a haunting vision of the future or a myth?
Pamela: Today it’s a myth. It’s not going to happen today. I’ve heard people say that if we mis-launch a satellite we’re going to cause a terrible chain reaction and satellites will run into each other and form a ring of debris.
Today it’s not going to happen. Today you could get two things hitting each other and maybe if everything is lined up and the universe ate the wrong thing for breakfast, maybe three things would hit each other. Which would be bad but not catastrophic in trapping us on the surface of the planet.
In the future, if we’re not careful and de-orbit things or grab things and bring them back down to the planet or put them somewhere useful we could end up with orbits that are so dense that you won’t be able to risk collision because one collision could lead to a chain reaction of thousands of collisions.
We’re not there. It’s not that dense. If you’re on the International Space Station looking around, you’re not going to see half a dozen Motorola cellular telephone satellites. You’re not even going to probably see one satellite.
Fraser: But you could imagine someday where the space station is having to be moved once a month, or week or day or every few hours to move out of the way of some piece of debris and all it takes is one catastrophic impact with the space station to end space stations as a concept, right?
Pamela: This isn’t a problem today. This isn’t something that we have to worry about today.
However, it is something that we do have to worry about for the future. It’s part of why NASA is periodically thinking about building little garbage detecting, garbage grabbing, dead satellite grabbing missions that will help clean up the orbit around the Earth.
Fraser: But the solution today is to be accountable. To make sure that you have a good strategy for dealing with anything that’s going to be left over in Space. Find a way to de-orbit your satellite when you ‘re done with it.
Or park it in some safe parking orbit and leave it there so that it’s out of the way and maybe could even be used for some future junkyard.
But it isn’t going to necessarily impact existing satellites and help set off that chain reaction. Let’s talk about other junk then.
Pamela: Where we smashed things into the planet Mars, the Eagle is somewhere dead and probably cratered.
Fraser: Well, let’s get closer to here first.
Pamela: Okay, so we left behind the moon landers. We left behind corner cubes that scientists shoot laser beams off of because we just like to shoot lasers at things. We have crashed multiple missions as a human race into the moon.
While attempting to do things that were scientific, we missed occasionally. There are dead former missions. There are former missions that worked and happily landed and took pictures. Their batteries are dead and the just sort of hang out cold and dead now.
We’ve scattered stuff all over the moon. It’s not a lot of stuff but it’s the sort of stuff you’re going to notice occasionally.
Fraser: But you can’t end up with a stable orbit around the moon, can you? You can’t have an object orbiting the moon for a hundred years. They all tend to crash.
Pamela: Yes you can.
Fraser: Can you?
Pamela: Yes, not a problem. The moon doesn’t really have an atmosphere. It has some but things can perfectly happily orbit. There’s both a Chinese and a Japanese mission currently orbiting the moon.
We’re planning to launch LRO and LCROSS later this summer to orbit the moon. Things orbit just fine. We do sometimes make mathematical errors or equipment errors and crash things. It’s what we do.
Fraser: Okay, so we’ve got the moon and then we have some comets, right? We’ve got deep impact.
Pamela: We have deep impact that we sent a chunk of into Temple 1 and then we’ve left things on Mars multiple times. We plunged Galileo into Jupiter.
Fraser: There’s a probe sitting on Titan, it’s the Huygens probe.
Pamela: There’s the Huygens probe on Titan and what’s fascinating is along with carrying metal and random chemicals and all sorts of other crazy stuff, they’ve also probably carried biologicals.
As well as leaving all sorts of random objects, we’ve also probably left random microbes all over the solar system. Most of them are probably dead, but you never know.
You never know what we might have inadvertently sent to Titan that could be unhappily attempting to survive on the surface of Titan right now.
Fraser: Right, I know that with a moon probe that was landed on the moon and with one of the Apollo missions they went and plucked off the camera from the mission and brought it back to Earth.
They found that microbes that had made the entire journey to the moon, sat on the moon several years, and then came back were still viable and were able to survive after given food and light they came back to life and were ready to go.
Pamela: There is an experiment done in some of the early days of the space shuttle where they launched a bunch of tomato seeds and exposed them to space for way longer than they meant to because of some problems with the space shuttle program.
When they brought the seeds back down, they gave them to schoolchildren all across the United States and the seeds grew.
Fraser: It really shows that for us space is very hostile but for bacteria, it’s really just a chance to have a nap. So beyond just the metal and bacteria, what else are we throwing into space? What trash are we creating?
Pamela: I’m not quite sure if trash is the right word but we’re also sending light waves, all different wavelengths. There is your cell phone communications.
Because of the cell phone signals that we all use, there are different frequencies that can no longer be used to look at galaxies because we can’t look through the wall of cell phone noise.
Fraser: Really? So there’s like pollution. Radio pollution has now made it so that we can’t look in certain wavelengths.
Pamela: Yes. It’s very problematic. There are different no fly zones where for instance the Iridium satellites used for some of the satellite cell phones they have to be turned off when they go over the Aricebo Observatory. They work in the same wavelengths that Aricebo is trying to observe the cosmos.
So pretty much the only place your satellite cell phone won’t work is at a radio observatory because we’re trying to protect the ability to see radio waves from the outer parts of the galaxy. The only way to do that is to not have all the cell phone signals.
Fraser: How much of a problem do you think this is? I’ve heard people wondering if extraterrestrials are going to be able to pick up our communications. Are they going to be annoyed by the amount of electromagnetic radiation that is leaking off of our planet?
Pamela: I don’t think we’re going to necessarily annoy anybody. It’s like the neighbor who has the Christmas light in their window that they never take down. It’s just sort of hanging out there and you’re aware of it.
You can see it. But it doesn’t necessarily cause you to have so much light coming into your bedroom that it keeps you awake at night.
Fraser: Right, with the vast distances and because we’re broadcasting in all directions not very much radiation is actually going to reach any other star.
Pamela: Pretty much the only people it is going to annoy are aliens who are trying to study the sun in radio light. Then there would just be this weird background hiss. It wouldn’t be that significant.
It would be this weird background hiss, accented with ‘I Love Lucy’, and the Olympic games and all sorts of other broadcasts that have now been traveling for fifty or sixty years across the Solar System and out of the Solar System to other stars.
Fraser: Can you think of anything else? What about neutrinos? Are we throwing out neutrinos from our reactors?
Pamela: We are throwing out neutrinos. I think there the numbers are just so low it doesn’t even matter. It’s like you and I are both producing dust. We’re human beings, we shed skin cells.
But in the grand scheme of all the sources of dust, my one source of skin cells on my body in my house really doesn’t change the dust levels.
The amount of neutrinos that the Earth is creating through all of its nuclear reactors compared to the sun is such a small number. It’s probably not that bad, but it’s there and it could be that they’re just enough different from the sun that someone who has perfected technology we haven’t yet, might be able to notice but probably not. The numbers are just way too low.
Fraser: But you never know what advanced technologies might be able to discover.
Pamela: So always leave room for miracles in scientific discovery.
Fraser: Right. Can you think of any other trash that we’re leaving out there or does that cover it?
Pamela: Metal space junk, biological junk and light junk pretty much sums it all up.
Fraser: All right. Thanks for that Pamela and we’ll talk to you next week.
This transcript is not an exact match to the audio file. It has been edited for clarity. Transcription and editing by Cindy Leonard.