Relevance: mains: G.S paper III: Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology.
Why in News?
- The amount of Indian space debris may have almost doubled in the aftermath of the Mission Shakti antisatellite strike but this is still significantly less than the existing space debris generated by China, Russia and the United States.
What are anti-satellite weapons?
- Anti-satellite missiles can be deployed against enemy satellites, disrupting crucial intelligence during war.
- Such a weapon allows for attacks on enemy satellites – blinding them or disrupting communications – as well as providing a technology base for intercepting ballistic missiles.
What is mission Shakti?
- Mission Shakti is an anti-satellite missile test conducted by India. · This was a technological mission carried out by DRDO.
- The satellite used in the mission was one of India’s existing satellites operating in lower orbit.
- With this test, India joins an exclusive group of space faring nations consisting of USA, Russia and China.
- DRDO’s Ballistic Missile Defence interceptor was used, which is part of the ongoing ballistic missile defence programme.
- The test was done in the lower atmosphere to ensure that there is no space debris.
What is space debris?
- Space debris is also called space junk.
- They 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 (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.
- As of 2018, the United States Space Surveillance Network was tracking more than 14,000 pieces of space debris larger than 10 cm (4 inches) across.
- It is estimated that there are about 200,000 pieces between 1 and 10 cm (0.4 and 4 inches) across and that there could be millions of pieces smaller than 1 cm.
- How long a piece of space debris takes to fall back to Earth depends on its altitude.
- Objects below 600 km (375 miles) orbit several years before reentering Earth’s atmosphere.
- Objects above 1,000 km (600 miles) orbit for centuries. Why concern about space debris?
- Because of the high speeds (up to 8 km [5 miles] per second) at which objects orbit Earth, a collision with even a small piece of space debris can damage a spacecraft.
- For example, space shuttle windows often had to be replaced because of damage from collisions with manmade debris smaller than 1 mm.
- The amount of debris in space threatens both manned and unmanned spaceflight.There are two key elements to addressing this global risk.
First, we need to start removing the most volatile and biggest pieces from the most congested orbits.
A number of companies, such as Astroscale and Saber Astronautics, are looking at this very complicated and technical solution already. The idea is essentially to grab a piece of debris with a special satellite and de-orbit both of them, in the process burning up both objects above the aforementioned ‘spacecraft cemetery’.
Other technologies include moving objects with a powerful laser beam. It is important to start doing that soon – current scientific estimates predict that without active debris removal, certain orbits will become unusable over the coming decades.
Though it is hard to capture objects that are moving as fast as this debris, it is certainly possible. After all, spacecraft dock with the ISS all the time.
The bigger issues are financing and international cooperation. The question of who pays for these ‘garbage collection’ missions is a tricky one. Perhaps even trickier, is negotiating the international diplomatic space and persuading, for example Russia, that their old military satellite needs to be de-orbited by a technology company.
The second part of the puzzle to ensure the long-term accessibility of orbits is to adjust our current behaviour in space in order to minimize the creation of new debris. We need to be more careful with existing operational satellites and new missions.
The UN guidelines on space debris mitigation are among the key international efforts to get different actors to follow proper rules of the road, but they are voluntary.
There are over 1,500 active satellites in various orbits, but this figure is set to grow dramatically over the coming years.
Large constellations that number hundreds and thousands of satellites, such as OneWeb and SpaceX, are being developed currently (mostly for LEO orbits), and promise to provide affordable connectivity to all parts of the world.
New governments are also entering the race to get access to space. The question is, with such an increase in traffic, how do we get all the private and public actors to think more sustainably?
The Global Future Council on Space Technologies is working on an industry framework to incentivize private actors to step up their act. Other efforts are needed.
Orbits are a critical part of the Earth environment, a global commons just like the oceans, and we need to protect this resource for future generations.