Science & Technology
27th Aug, 2019
A majority of the debris created by India’s anti-satellite test seem to have disintegrated according to the latest assessment of space debris by NASA.
- India had shot down its 740-kg Microsat-R satellite on March 27 this year in a demonstration of its capability to destroy the space-based infrastructure of an enemy country.
- That anti-satellite test made India only the fourth country in the world to have demonstrated this capability.
- The destroyed satellite had disintegrated into several small and big pieces, and added to a large amount of debris in space, which is considered a threat to functional satellites and other space assets.
- At that time, India had said that since the test was carried out in the lower atmosphere, it did not expect to add any significant amount of space debris.
- Space debris, also called space junk, 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 (1,200 miles) of Earth’s surface; however, some debris can be found in geostationary orbit 35,786 km (22,236 miles) above the Equator.
- Kessler syndrome postulates that crashes would first be seen between fragments and larger objects like satellites and would eventually be between two fragments. Crashes will continue till the debris becomes very small.
- There is almost 7,000 tons of active space debris—from old satellites and spacecraft to lost components and spent rocket parts—orbiting Earth at any given moment. While some of the space junk in orbit decays with time, debris that is located at a higher orbit can take years to disintegrate.
- There is no binding international legal rule (yet) which prohibits the wanton creation of space debris.
- 1967 Outer Space Treaty bars states party to the treaty from placing weapons of mass destruction in Earth orbit.
- Since 2002, the world's space powers have complied with an informal code of conduct to avoid the creation of space junk and the United Nations has endorsed a resolution along those lines.
Removal of debris
There have been several initiatives to remove debris like global mitigation measures by Committee on the Peaceful Uses of Outer Space, and Inter-Agency Space Debris Coordination Committee (IADC) ; e-Deorbit mission of European space agency etc. However RemoveDEBRIS mission launched by European Union is a significant one.
The RemoveDEBRIS mission is led by the Surrey Space Centre (SSC) at the University Of Surrey, UK, and is co-funded by the European Commission and other partners, including prominent European space companies and institutions.
Rather than engaging in active debris removal (ADR) of real space debris, the RemoveDEBRIS mission plan is to test the efficacy of several ADR technologies on mock targets in low Earth orbit.
- It showcases four methods of capturing artificial debris targets.
- The targets are two CubeSats (miniaturized satellites provided by the SSC) that are carried inside the main platform.
- The first demonstration involves a net that is deployed (net capture) at the target CubeSat.
- The second experiment sees the use of a harpoon, which is launched at a target plate made of “representative satellite panel materials". This is a first-of-its-kind harpoon capture in orbit.
- The third experiment using the other CubeSat involves vision-based navigation. Using cameras and LiDAR (light detection and ranging), the platform sends data about the debris back to the ground for processing.
- The fourth experiment sees the RemoveDEBRIS spacecraft deploy a large dragsail to speed up its de-orbiting process. As it enters Earth’s atmosphere, the spacecraft will burn up, leaving no debris behind.