A look at plans pitched by scientists to clear space debris

On 27 March, India announced the successful launch of its first anti-satellite (ASAT) weapon. The interceptor destroyed a test satellite at a 300-kilometre altitude in low earth orbit (LEO), thus successfully testing its ASAT missile. With this test, India became the fourth nation after the US, Russia and China with anti-satellite missile capabilities.

Ever since the news came up, some western scientists voiced concern over the space debris that has emerged following the missile test. What are space debris?

* Space debris
Space debris, also called space junk are artificial material that is orbiting Earth but is no longer functional. This material can be as large as a discarded rocket stage or as small as a microscopic chip of paint. Much of the debris is in low Earth orbit, within 2,000 km of Earth’s surface while some debris are 35,000 km above the equator. It is estimated that there are about 2 lakh pieces between one and 10 cm across and that there could be millions of pieces smaller than one cm. Objects below 600 km orbit for several years before reentering Earth’s atmosphere whereas objects above 1,000 km orbit for centuries.

* Dangers of space debris
Junk in space hurl at a speed of over 20,000 km/hr. The chances for them to strike a satellite is always high and this keeps scientists on their toes to bring in ideas to clear the trailing mess. When space debris impact other satellites, it can decimate and cause communication failure. Scientists and aerospace engineers have come up methods to ‘clean’ space.

* The e.DeOrbit mission
First proposed publicly in 2014, the aim is to seek out satellite debris in a polar orbit at an altitude between 800 and 1,000 kilometers. The European Space Agency is considering several kinds of ‘capture mechanisms’ to pick up the debris, such as nets, harpoons, robotic arms and tentacles.

*Phoenix
A mission launched by United States Defense Advanced Research Projects Agency in which the robotic spacecraft will look for derelict satellites and harvest the still usable hardware. The service satellite will be able to attach a module that allows broken or salvaged parts to be reused for new missions. Likewise, there is another project called ‘CleanSpace One’, a robotic janitor that is launched into the space from an airplane. The janitor grapples the faulty satellite and plunges back into the Еarth’s atmosphere. It will destroy itself along with the derelict satellite on the way back.

* Earth-Based Lasers
Earth-Based Lasers might seem like something we see in Star Wars. According to scientists, setting lasers to deorbit might be the easiest way to bring down unwanted floaters. But these lasers wouldn’t be powerful enough to blast a satellite out of the sky. They would rather be shone on the debris for several hours until it slowed down and would gracefully fall into the atmosphere and burn up upon reentry.

NT Bureau