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Explained: The ABC of India’s anti-satellite missile test

Why shooting down a satellite, apart from being a technology stride, gives India a new strategic weapon

Written by Amitabh Sinha | Pune |
Updated: March 28, 2019 9:05:00 am
Explained: The ABC of India's anti-satellite missile test Called ASAT in short, it is the technological capability to hit and destroy satellites in space through missiles launched from the ground.

India announced to the world Wednesday that it had carried out a successful anti-satellite missile test, becoming only the fourth country to do so. With Prime Minister Narendra Modi coming on television himself to make the announcement, the test is being described as a giant technological and strategic development for the country.

What is an anti-satellite missile test?

Called ASAT in short, it is the technological capability to hit and destroy satellites in space through missiles launched from the ground. Early Wednesday, scientists and engineers at Defence Research and Development Organisation (DRDO) launched a missile from the Dr A P J Abdul Kalam Island launch complex near Balasore in Odisha that struck a predetermined target: a redundant Indian satellite that was orbiting at a distance of 300 km from the Earth’s surface.

But why would one want to hit and destroy a satellite?

The technology is aimed at destroying, if necessary, satellites owned by enemy countries. The test, however, can be carried out only on one’s own satellite. There are a large number of satellites currently in space, many of which have outlived their utility and orbiting aimlessly. One such satellite was chosen for the test. India did not identify the satellite it had chosen to hit for the test. But official sources said the satellite that had been knocked out was Microsat R, a micro-satellite launched by ISRO on January 24 this year. The satellite was manufactured by DRDO.

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Satellites are extremely critical infrastructure of any country these days. A large number of crucial applications are now satellite-based. These include navigation systems, communication networks, broadcasting, banking systems, stock markets, weather forecasting, disaster management, land and ocean mapping and monitoring tools, and military applications. Destroying a satellite would render these applications useless. It can cripple enemy infrastructure, and bring it down on knees, without causing any threat to human lives.

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If it is so potent, why do only few countries have it?


It requires very advanced capabilities in both space and missile technologies that not many countries possess. But more than that, destroying space infrastructure like satellites is also taboo in the international community — at least till now — just like the use of a nuclear weapon. Almost every country agrees that space must not be used for wars and has spoken against weaponisation of space. There are international treaties governing the use of space, that mandate that outer space, and celestial bodies like the Moon, must only be exploited for peaceful purposes.

There is a Outer Space Treaty of 1967, to which India is a signatory, that prohibits countries from placing into orbit around the Earth “any objects carrying nuclear weapons or any other kinds of weapons of mass destruction”. It also prohibits the stationing of such weapons on celestial bodies, like the moon, or in outer space. “The moon and other celestial bodies shall be used by all state parties to the treaty exclusively for peaceful purposes,” it says.

There are at least four more multilateral treaties that deal with specific concepts agreed to in the Outer Space Treaty. None of these, however, prohibits the kind of test that India carried out Wednesday.


But there is a more compelling, practical and selfish reason for countries not wanting to destroy each other’s satellites — the problem of space debris.

Click image to enlarge

Why is space debris such a big problem?

Anything launched into the space remains in space, almost forever, unless it is specifically brought down or slowly disintegrate over decades or centuries. Satellites that are past their life and are no longer required also remain in space, orbiting aimlessly in some orbit. According to the September 2018 issue of Orbital Debris Quarterly News, published by NASA, there were 19,137 man-made objects in space that were large enough to be tracked. These included active and inactive satellites, rockets and their parts, and other small fragments. Over a thousand of them are operational satellites.

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Besides these, there are estimated to be millions of other smaller objects that have disintegrated from these and keep floating around in space. According to the European Space Agency, there were an estimated 7,50,000 objects of size one cm or above in space.


A satellite that is destroyed by a missile disintegrates into small pieces, and adds to the space debris. The threat from the space debris is that it could collide with the operational satellites and render them dysfunctional. According to the ESA, space debris is one of the principal threats to satellites.

When China carried out its first anti-satellite missile test in 2007, destroying its Fengyun-1C weather satellite, it created more than 2,300 large pieces of space debris, and an estimated 1.5 lakh pieces of objects that were larger than 1 cm in size. Each of them could render a satellite useless on collision.


With countries launching more and more satellites, each one of them being a strategic or commercial asset, avoiding collisions could become a challenge in the future. Countries do not want to complicate matters by creating more debris in space.

Didn’t Indian test add to the debris?

It did, but it is too early to say by how much. The Ministry of External Affairs, in its statement Wednesday, said the Indian test was done in the lower atmosphere to ensure that there was no space debris. “Whatever debris that is generated will decay and fall back on to the earth within weeks,” it said. The satellite hit during the Indian test, as stated, was orbiting at 300 km from Earth’s surface. Several analysis of the Chinese test of 2007, which had targeted the satellite placed at more than 800 km from Earth’s surface, said that the debris created in that test would remain in space for several decades, possibly centuries.


Read | India had capacity to build anti-sat missiles for long: DRDO ex-chief

What signal does the test send to the world?

While the government has conceded that India has long had ASAT capabilities, this is the country’s first demonstration to the world. It has shown that it is capable of bringing down a satellite, and disrupting communication. Because the test was carried out on a satellite placed in the low-earth orbit, one might question whether India can hit any satellite. Targeting satellites in the higher orbits, however, is only a matter of scale — of powering the rockets enough to go deeper in the space. Many of the most strategic satellites are placed in orbits that 30,000 km from earth’s surface or even higher. DRDO scientists claim India has the technology to target these as well.

The BMD Interceptor takes off from the Dr A P J Abdul Kalam Island, off Odisha. (PTI)

But could this trigger similar tests by other countries?

Unlikely. The countries that have the capability, and intended to carry out the tests, have already done so. The first anti-satellite test (ASAT) was carried out by the US military way back in 1959. The then Soviet Union followed a year later. Thereafter, the two countries carried out a series of such tests up till early 1980s. After that there was a lull, broken only by the Chinese test in 2007. A year later, US brought down a non-functional spy satellite. Other countries which could have the capability, like Israel, have not shown an intention to test.

How does the world generally react to such tests?

Technically, if the Prime Minister had not announced it himself, the world would not have known, at least immediately, of the test since only India’s own satellite was affected. As is mandatory for any missile test, India did issue a Notice to Airmen (NOTAM) to airline authorities across the world informing them about an impending missile test. This notice does not have to specify the kind of missile being tested, only the flight path and the region affected, so that airborne systems are able to avoid it.

The Chinese had withheld the information about their 2007 test for 12 days before announcing it. It had triggered an international outcry, but that was also because of the very large amount of debris created.

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Is this the only way to target enemy satellites?

In the last few years, countries have explored alternative options of making enemy satellites dysfunctional, options which do not involve direct destruction of the target or creation of the debris. For example, technologies have been developed to jam the communication from the satellites by interfering with its radio signals. This can be attempted during the uplink or the downlink.

Another option that has been explored is the possibility of sending satellites that could just approach a target close enough to deviate it from its selected orbit, without destroying it. Several countries and organisations including China, Japan, Russia and the European Space Agency are said to be working on developing these ‘close proximity’ anti-satellite technologies.

The third option is the possible use of ground-based lasers to ‘dazzle’ the sensors of the satellites and make them at least “partially blind” so that they are unable to work efficiently.

None of these technologies is mature enough to be deployed or tested.

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First published on: 28-03-2019 at 03:44:13 am
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