New Space Fence Could Prevent Real Life 'Gravity'

May 9, 2014

In the blockbuster film “Gravity,” astronauts became stranded, floating in orbit after “space junk” hit their mission at a heart-racing speed. While the film is more science fiction than fact, there are huge concerns about all the debris in the Earth’s orbit, and how that could affect satellite systems.

Sixty years of activity in space have resulted in about 500,000 pieces of space debris. The detritus ranges from left-over pieces of rockets to a glove that an astronaut dropped in 1965. All of that material has the potential to collide with the 1,100 satellites over the Earth.

The House Committee on Science, Space and Technology held a hearing Friday on how to monitor and reduce the space junk. The Air Force is expected to award a contract in the next few weeks for a “Space Fence.” The fence isn’t really a fence. It’s a radar system that projects a wall of energy into space to track all the bits of junk floating around.

The Air Force shut down its old space fence last year, citing budget concerns. The new fence, expected to come online in 2019, would be even more powerful, with the ability to track objects 5 centimeters in size and larger.

Brian Weeden, an expert on space junk and technical adviser with the Secure World Foundation, testified at the hearing. He said another concern is getting rid of all the junk in space. But it isn’t easy.

“You can imagine a city bus that has been undergoing extreme heat and cold changes for decades, also being imposed with hard radiation, and it’s probably very fragile and brittle. And it’s got a bunch of explosive fuel in it. And it’s spinning. Now — go grab it,” Weeden tells Here & Now’s Jeremy Hobson.

Weeden said under a best case scenario, up to ten pieces of the largest debris would be removed from space a year. But he said the better plan would be to ensure that we have a more sustainable approach to space travel, so we leave less junk behind going forward.


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Today on Capitol Hill, lawmakers held a hearing on something that will sound familiar if you've seen the movie "Gravity."


AMY WARREN: (As Explorer Captain) Ready to receive.

GEORGE CLOONEY: (As Matt Kowalski) Houston, elaborate.

ED HARRIS: (As Mission Control) Debris from the missile strike has caused a chain reaction hitting other satellites and creating new debris. Traveling faster than a high speed bullet up towards your altitude. All copy?

CLOONEY: (As Matt Kowalski) Copy all.

HOBSON: In the movie, a field of space junk takes out space vehicles and astronauts, and that was fiction, of course. But the issue of space debris is real, and Congress is considering funding a new space fence to monitor all of it. For more on that, Brian Weeden, space junk expert with the Secure World Foundation joins us. He testified at today's hearing. Brian, welcome to HERE AND NOW.

BRIAN WEEDEN: Glad to be here.

HOBSON: Well, first of all, you say what happened in "Gravity" is pure science fiction, right? That's not realistic?

WEEDEN: Well, there is a kernel of truth there. The growing amount of space debris does present a threat to spacecraft and satellites in orbit. And we have seen collisions between objects in orbit. The part where they departed from reality into what makes a good dramatic movie was how quick it all happened. And then the devastating aftereffect was then created for a very entertaining movie plot.

HOBSON: Okay. Well, how much junk really is up there right now?

WEEDEN: At the moment, there are a little over 1100 active working satellites that provide a whole bunch of benefits down here on Earth. Alongside those satellites, there are an estimated half a million pieces of space debris that are the leftover remnants from the last 60 years of our activities in space.

HOBSON: And they're all moving very fast.

WEEDEN: Absolutely. They could be moving as fast as, you know, 10 kilometers per second, which equates to somewhere around 25,000 miles an hour.

HOBSON: And up until last year, there was this thing that we called a space fence that goes back to the Cold War. Tell us a little bit about the previous space fence, and then I want to hear about what is coming soon.

WEEDEN: Sure. The U.S. military operates a global network of tracking sensors that are largely make up of radars and optical telescopes. These are located around the world, and the military uses them to track not only all the satellites, but a good portion of all that debris in orbit. And the main purpose of all of this is to help protect satellites against threats, both natural and manmade threats.

One of these sensors was known as the space fence, and it was a series of installations strung out across the entire southern United States from the West Coast all the way to the East Coast. And it projected a wall of radar energy up into space. And anything passing through that radar wall would generate a return, and then you could know if something went through and you could generate a track for those objects.

Late last summer, early last fall, the U.S. Air Force made a decision to shut down that space fence in part because of budget constraints, but also because they were really interested in making a case to buy a new one.

HOBSON: Well, tell us about the new one and how it's different from the old one.

WEEDEN: First of all, it's not going to be located in the U.S. It's going to be located in the middle of Pacific Ocean at a place called Kwajalein Atoll, which is where the Air Force and the U.S. military already have a number of sensors and facilities. That puts it closer to the equator, which puts it in a little bit better position to track certain kinds of objects in orbit.


WEEDEN: The really big change is that they plan to have this new fence be able to track much small objects than they can currently track. At the moment, the Air Force's network is limited tracking things bigger than about 10 centimeters or about four inches in size. That's only about 23,000 objects out of that half million.

HOBSON: Brian, let's back up and talk about the problem.


HOBSON: Because even if we can track these objects, there are still clearly a lot of things up there that could run into each other and could cause problems, and we're sending more stuff up all the time. Are we putting too much into space?

WEEDEN: No, because the active satellites that we get value from are still a very small portion of it. And they do provide some amazing services, everything from GPS that helps us navigate to satellite TV and global communications to everything we know about the Earth's weather and be able to predict weather forecasting. And also studying climate and understanding the Earth itself.

The vast majority of all of that comes from satellites. So they do provide incredible value.

HOBSON: Sure. But there are a lot of them up there and they sometimes run into each other.

WEEDEN: Well, so it's more about the satellites running into all this leftover debris. And so the question is how can we use space more responsibility into the future. And that means, you know, in our future activities, doing them in a way that generates less debris, and then figuring out how it is we're going to deal with this existing legacy problem.

HOBSON: So how do we do that?

WEEDEN: It's really challenging when you start thinking about removing things from space. You can imagine a city bus that has been undergoing extreme heat and cold changes for decades also being imposed with hard radiation, and it's probably very fragile and brittle. And it's got a bunch of explosive fuel in it, and it's spinning.

HOBSON: That's a problem.

WEEDEN: Now, go grab it. And by the way, there are hundreds of those. So on one hand it's a very difficult engineering problem, but they're making some progress on some ideas. It's not going to be possible to remove it all.

HOBSON: Brian, just give us the stakes here. For us, right here on Earth, if something crashes into a satellite, is it just that HBO goes out or are those consequences bigger?

WEEDEN: That honestly really depends what the satellite is. You mentioned something like HBO. Those satellites are actually located 36,000 kilometers or 22,000 miles above the earth. That is far above where the worst debris is.

The worst debris is concentrated between 800 and 1,000 kilometers or around, you know, 600 miles, somewhere in that region. That's where the worse debris is. And what's really there are a lot of weather satellites, imagery satellites that provide more of like public services and public benefits.

And the concern is not that there's going to be an event that suddenly takes out some massive capability. It's actually the increasing costs. Some people made the comparison between this and climate change, in a way, in that we have to deal with something now that's going to cost us money now to potentially avoid bigger costs in the future.

HOBSON: Which is for climate change has been a very hard case to make, for a lot of people.

WEEDEN: Absolutely. Absolutely. And the two are not completely analogous but there is enough of a similarity there that we're seeing some of the same challenge on the space debris side.

HOBSON: So when could a new space fence be up and running?

WEEDEN: The Air Force plans to award the contract to one of the two companies that bid on it sometime very, very soon. Once that's awarded, they've said that the new space fence will be up and running sometime around 2019.

HOBSON: Brian Weeden, technical advisor with the Secure World Foundation. He testified at today's House hearing on space traffic management. It was called "How to Prevent a Real Life 'Gravity'." Brian, thanks so much.

WEEDEN: You're welcome.

HOBSON: And you're listening to HERE AND NOW.

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