How To Clean Up Space Junk
On October the fourth, 1957, the first satellite, Sputnik I, was launched into space. Although it burned up in the atmosphere three months later, many satellites launched since then have not, leaving us with a virtual junk yard orbiting the earth. Now, those debris represent a real threat to the television communications and GPS satellites, not to mention the astronauts. But luckily, the Swiss have a plan to clean up space. So I have come to Lausanne to figure out how they are going to do it.
Most of the space junk orbiting earth is within 2000 kilometers of the earth’s surface. There are over 22,000 objects larger than this softball and over half a million larger than this marble. Now, all of the orbiting debris is going about seven to eight kilometers per second, but since the objects are moving relative to one another, the average speed of a collision is about 10 kilometers per second. And an object this size going 10 kilometers per second has about the same impact as a midsize car going nearly 200 kilometers per hour. That is enough force to destroy any satellite in orbit.
As a veteran of four space flights, Swiss astronaut Claude Nicollier knows the dangers first hand.
“Only the large debris are tracked. By radar we know the orbit exactly and sometimes we have to be a small change in the orbiter characteristics that our spaceship, the space shuttle...”
“Space shuttle Endeavor...”
“...because it is foreseen that next day or two days later we are going to have a close approach with a debris, such that NASA was not feeling too good about that, and we translated our orbits so to make that distance a little bit larger.”
Fortunately, to date, there haven’t been any serious collisions with manned spaced craft. But in 2009, a single crash between two satellites added a whopping 2000 new pieces of debris.
“If we don’t do anything, space will become soon inaccessible because of the large amount of debris and the high risk of collision.”
So the Swiss, determined to do something about that problem, are extending their clean country reputation into outer space.
“The Swiss space center has launched a program called Clean Space One that is a demonstrator of the capability to remove debris. And the idea is to go and to remove one of two satellites from Switzerland.”
“One of these two satellites is appropriately named Swiss Cube.”
“Swiss Cube is a small satellite which you see. This is a one to one model. So this is in the right scale. It belongs to Switzerland. So we had to do something about this.”
“You can’t have Swiss junk just floating around in space.”
“No. No. That is not acceptable.”
So the mission for Clean Space One is a proof of concept that a janitor satellite can be sent into space to grab a piece of space junk—in this case Swiss Cube and bring it back into the atmosphere where it will burn up. To rendezvous with the space junk, the small janitor needs an incredibly efficient engine. Working on the challenge is Professor Herbert Shea, an expert in micro mechanics.
“This is your propulsion system.”
“This is our propulsion system. Little silicone micro machine chips. We use something called electro propulsion, which allows you to emit single atoms that are electrically charged and use an electric field to accelerate them out. So you are not burning them. You are emitting your propellant. And that is what many small satellites use, but nothing has been, to date, been able to make something this small. So we do zero to 60 miles an hour in about three days. But laughable as it seems to all of us, because there is no friction in space, or negligible friction, then if we wait six months, we have a huge change in speed. And that is how the mission will be done.”
“Once propelled into the correct orbit, the next challenge is to grab the space junk, an object tumbling around uncontrollably without creating more debris.”
“Our idea is to use a very compliant system. Kind of think of an octopus arm. An octopus arm is very soft, but it can grab any strange shape and wrap around it and hold it. And we will have a grabber that looks, in a very, but that real one will be more sophisticated. But it looks like this. So it is basically very, very soft elastomer. I will turn it on in a minute. You can see how soft it is. And the idea is this will be rolled up so it doesn't take up much room. You get into... and it will have 10 of these in a series. You get into space, you unroll it. And then these things can open when you turn the voltage on. You are able to open this and you turn the voltage off and it wraps it around and it holds the satellite.”
“Is this going to be a little bit like those games where you are trying to pick up a stuffed toy in the arcade and drop it somewhere? Is it going to be like that?”
“Essentially, yes.”
“Because those games... those games can be incredibly frustrating with those little arms.”
“They are built to be frustrating.”
“Whereas this, this is built to be...”
“This is built to succeed.”
“Can I ask? Has anyone ever successfully gone up and grabbed a piece of space junk and gotten rid of it?”
“To my knowledge, no. It has never been done before.”
“And it grabs on.”
Ambitious as it may sound, the Swiss know how vast this junk yard is. So their ultimate aims are more modest.
“Hopefully starting in, say, 2020 to do systematic removal of the large debris at the rate of five or more per year in order to contain the increase of the debris density in lower earth orbit. Then space will continue becoming accessible. Of course, the exposure to the space environment is a wonderful thing.”