MARCO WERMAN: Every year, we send more and more material into space. Some would call it a junkyard up there. There are thousands of satellites, working and not, orbiting above the Earth's surface, so accidents happen. NASA scientists have reported a major collision involving two intact satellites about 600 miles above Siberia. The collision has created two huge clouds of debris. John Logsdon is Professor Emeritus at George Washington University, and former director of the Space Policy Institute. He joins us from Washington. I remember seeing a rendering of all the junk floating above the Earth a few years ago. Each dot, of course, wasn't really to scale, but you could barely see the Earth in the drawing. With everything floating up there, John Logsdon, why doesn't this happen more often?
LOGSDON: Well, to use a cliche, there's a lot of space in space. Yes, there is a lot of small pieces of debris, abandoned rocket stages, satellites that are no longer functional, and something like 850-900 operational satellites, in a pretty large volume of space.
WERMAN: Do you know the number of how much stuff is up there; leftover junk from old missions and old launches?
LOGSDON: The U.S. Space Command tracks the objects in space greater than 10 cm in size. They track about 10,000 objects, but there are lots that we don't track that are smaller than 10 cm; lots and lots basically.
WERMAN: If you are aware that satellites orbiting the Earth might crash into each other, are there any options to changing the directions of those satellites to avert the collision?
LOGSDON: One of these satellites ? a Russian military communication satellite ? had been dead for 10 years, and probably there was no way of controlling it. I, frankly, don't know whether the U.S. Iridium satellite had maneuverability aboard. Some satellites do. Certainly things like the space shuttle and the International Space Station do. If there's a prediction of an impact, they can maneuver and get out of the way.
WERMAN: Who predicts? Who's watching this stuff?
LOGSDON: The U.S. Air Force; the Space Command operates a global system of sensors that provides what is called space situational awareness. It's not a perfect system. There've been a lot of proposals to upgrade it, so there's a lot going on up there that we don't have a good visibility into too.
WERMAN: Was the Air Force watching this particular event prior to its happening?
LOGSDON: It's likely they were. These were two fairly large objects on a trajectory that would bring them either near to one another, or in a collision. One would certainly hope that we were aware of that kind of possibility.
WERMAN: Is the Air Force the only body monitoring what's going on up in space?
LOGSDON: Yes, in terms ?
WERMAN: The Russians aren't?
LOGSDON: Europe has some capabilities. Russia has some capabilities. By far, most of the information comes out of this Air Force system.
WERMAN: Are there laws that govern space in the way there are laws that govern international waters?
LOGSDON: Yes. Not surprisingly, the lawyers are buzzing the Internet about this collision. There is a treaty on liability ? to which both the United States and Russia are signatories ? that says whoever is responsible for this must pay the damages.
WERMAN: What does a satellite cost?
LOGSDON: The Russian satellite was a classified military satellite, so ?
WERMAN: We won't know its price tag.
LOGSDON: There's no way of estimating what its cost would be.
WERMAN: The Iridium satellite?
LOGSDON: The Iridium satellites ? there are 66 operating, and a few spares in orbit. Iridium says that losing one satellite is not going to affect its operations. I don't have a number off the top of my head, but I'd guess $50 million; maybe less since there's so many of them.
WERMAN: If lawyers are buzzing today about liability issues, at some point I suspect somebody's going to start talking about how to clean all this stuff up?
LOGSDON: People have been thinking about that for a long time, and haven't come up with any really good ideas. The focus is on preventing future debris creation. The United Nations adopted some guidelines early last year that had been worked up through the Committee on the Peaceful Uses of Outer Space. Those are voluntary guidelines of good behavior.
WERMAN: This may be stupid, but it's my stupid question.
LOGSDON: There are no stupid questions.
WERMAN: Why doesn't all of this fall to Earth and burn up?
LOGSDON: Much of it is at an orbital altitude that's so high that there is no resistance. It's moving at orbital speeds, and there's nothing to slow it down. For it to drop back to Earth it has to slow down below 17,000 miles an hour and re-enter the atmosphere. Some of this stuff will be there for the indefinite future.
WERMAN: John Logsdon, Professor Emeritus at George Washington University, and the former director of the Space Policy Institute. Thanks for explaining this "space junk" to us.
LOGSDON: Okay, good to talk to you.