FP ExplainersApr 11, 2022 15:03:21 IST
We have a space problem and when we say space, we don’t mean area wise, but we are talking about the cosmos!
According to the most recent report of Orbital Debris Quarterly News, published by NASA’s Orbital Debris Program Office, there are 25,182 pieces of space debris, of sizes larger than 10 cm, in the lower earth orbits which are within 2,000 km of earth’s surface.
Of these, India is responsible for only 114 space debris objects, whereas the United States has 5,126 objects that can be categorised as space debris in the earth’s orbit and China has 3,854 objects, including spent rocket bodies, orbiting the earth.
The report also mentioned that India’s space debris levels had come down to the 2018 levels after it saw a spike in 2019 when it conducted its first-ever anti-satellite test.
Also read: 27,000 man-made objects in Earth orbit, and counting: Space junk is here to stay
Before we delve into the report more, let’s understand what space debris is and why it could be a problem.
What’s space debris?
Space debris, also known as space junk, is any man-made object in orbit about Earth which no longer serves a useful purpose.
Big objects such as dead satellites that have failed or been left in orbit or smaller things, like bits of debris or paint flecks that have fallen off a rocket are all prime examples of space debris.
Britannica explains that 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, though some debris can be found in geostationary orbit 35,786 km (22,236 miles) above the Equator.
According to experts, all space junk is the result of us launching objects from Earth. Debris or satellites left at higher altitudes of 36,000 kilometres — where communications and weather satellites are often placed in geostationary orbits — can continue to circle Earth for hundreds or even thousands of years.
In other cases, space junk can be caused when two satellites collide or during anti-satellite tests.
Anti-satellite tests are rare, but there have been instances when the US, China and even India used a missile to blow up their own satellite, causing thousands of new pieces of debris.
India’s anti-sat test and resulting debris
The issue of space debris first became big news when India conducted Mission Shakti, an anti-satellite missile test, from the Dr A P J Abdul Kalam Island launch complex on 27 March 2019.
.@DRDO_India successfully launched the Ballistic Missile Defence #BMD Interceptor missile, in an Anti-Satellite #ASAT missile test #MissionShakti engaging an Indian orbiting target satellite in Low Earth Orbit (LEO) in a ‘Hit to Kill’ mode from the Dr. A.P.J. Abdul Kalam Island pic.twitter.com/n5DEWLQpSp
— PIB India (@PIB_India) March 27, 2019
In the test, India destroyed a defunct Indian satellite orbiting at 300 km. The incident became big news as India became only the fourth nation behind the US, China and Russia to possess such technology.
Prime Minister Narendra Modi had hailed the move and said it was ‘historic’.
In the journey of every nation there are moments that bring utmost pride and have a historic impact on generations to come.
One such moment is today.
India has successfully tested the Anti-Satellite (ASAT) Missile. Congratulations to everyone on the success of #MissionShakti.
— Narendra Modi (@narendramodi) March 27, 2019
However, the move attracted NASA’s criticism with its administrator — Jim Bridenstine — saying the test had created 60 pieces of orbital debris big enough to track, 24 of which rise higher than the International Space Station’s orbit around Earth.
Bridenstine had then said that such moves were unacceptable. “That is a terrible, terrible thing, to create an event that sends debris in an apogee that goes above the International Space Station,” Bridenstine said at a town hall meeting, which was livestreamed on NASA TV. “And that kind of activity is not compatible with the future of human spaceflight that we need to see happen.”
A year later, NASA found at least 28 pieces of debris from the A-SAT missile test, according to a report published in The Print.
According to Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, NASA has tracked at least 101 pieces of debris from the A-SAT test initially, of which 28 were in low Earth orbit.
Perils of space junk
The biggest problem with space junk is the danger it poses is to other satellites in orbit. The space debris can hit and potentially damage or destroy these satellites.
The debris can also increase the cost for satellite operators. Industry experts have estimated that protection and reduction efforts dealing with space junk make up about 5-10 per cent of satellite mission costs.
Space debris could also potentially create unusable regions of orbit due to pollution.
Can we clean up space junk?
According to NASA, debris in orbits below 600 kilometres will fall back to Earth within several years, but above 1,000 kilometres it will continue circling the Earth for a century or more.
Japan’s Aerospace Exploration Agency tied up with Astroscale, a Japanese start-up, to find and retrieve used satellites and other space debris.
The European Space Agency is working with Swiss start-up ClearSpace for launching a mission in 2025.
In India, the Indian Space Research Organisation (ISRO) was looking into the technologies required to undertake active debris removal.
Minister of State in the PMO Jitendra Singh said ISRO had set up the Directorate Space Situational Awareness and Management to deal with issues related to space debris.
With inputs from agencies
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