Attention, everyone between Canada and South America: In the next few days a retired satellite will crash in your area. It will break into pieces during its chaotic descent to Earth, but 26 large fragments weighing up to 150 kilograms will land in an 800 kilometre-long area.

Space junk falls down to Earth every day, but this is the largest satellite to do so.

“For obvious reasons, the amount of space debris has increased since the beginning of the space age,” Nicholas Johnson, NASA’s Chief Scientist for Orbital Debris, tells Metro. “Even though on average one piece of space debris falls down to Earth every day, nobody has been injured. Rockets and satellites burn up in the atmosphere and come down as smaller pieces. Most of those pieces have landed in oceans and places like Siberia.”

But the amount of space junk is growing. Today, some 22,000 large pieces – and countless smaller ones -- fly around in orbit at speeds of up to 12 kilometres per second. “When a spacecraft completes its mission it becomes debris,” explains Johnson. “You can either drop it into an ocean or send it higher into space.”

 

On their way the junk pieces pass the many crucial installations that now inhabit space: communications satellites, spacecraft, even the International Space Station. And the danger of space crashes is growing, too.

“The more objects we put into space, the more ‘junk’ that we create, explains Sigrid Close, a professor of astronautics at Stanford University. “The risk of impact by a meteoroid or space debris increases, simply because the number of objects in space has gone up. Even the smallest particles can cause catastrophic damage due to the relatively high speed of the particle.”

The amount of debris has reached now reached a dangerous level, warns the US National Research Council in a new report. “It reached a threshold where it will continually collide with itself, further increasing the population of orbital debris”, writes the Council. And, Close says, meteoroids – small, natural space pieces that exist by the billion – pose an even larger crash risk. Planes are hit by meteoroids on average once per year.

However, there is some consolation for those fearing an invasion of rocket chunks at the end of this month as NASA will be able to pinpoint the landing area two hours before the pieces crash down.

Robots, fetching debris

NASA and other space agencies know where the old satellites are. In fact, they put them there, in “non-usable” orbits, away from active satellites. But the problem are not the retired space machines – it’s the debris they turn into when they burn up.

“Debris removal is a very big topic right now,” says Sigrid Close. “For the large objects, we talk about sending up robots to grab the debris and throw it away from Earth. For small objects, we look at things like laser ablation that changes the properties of the debris, thereby allowing it to re-enter the Earth and burn up quicker than it would have otherwise.”

As for meteoroids, there’s little humans can do to remove them since they’re attached to a parent comet or asteroid.



“Small risk of space terrorism”

An interview with Petr Topychkanov, Coordinator of the Nonproliferation Program at Carnegie Moscow Center

Another concern is terrorists targeting space installations. How big is the risk of such attacks?

Theoretically terrorists could use missiles stolen from armed forces to target satellites. And they could attempt to send wrong radio signals to satellites to change their activities. During the past several years there have also been a number of incidents of people pointing lasers at airplanes to make pilots’ work harder. This example shows that the technology development can give more options to malefactors. In the near future the new technologies may be available for terrorists who will try to use them against objects in space.



If they targeted space installations, how much damage could terrorists do?

They could damage the satellites’ communication between each other in space or details of the satellites on the ground. The sabotage in space programs on the ground is most likely in the countries where there is a high risk of infiltration of extremist and terrorist elements into government services.

Is there a bigger risk of terrorists attacking space than subways?

Right now the risk of space terrorism is very small because terrorists don’t have enough resources to carry out such attacks. And remember that terrorists want to terrorize people. If you attack a target on the ground, people see it. If you attack a space satellite and knocked out people’s mobile phone networks, they’d feel it was a disaster. Still, you’d have to prove that you did it. Terrorists don’t just want to create havoc, they want to be famous.

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