BharatNotes What is ASAT (Anti-Satellite) Weapon?
An anti-satellite (ASAT) weapon is any system built to neutralise an adversary's satellites — by physical destruction, by disabling their electronics, or by disrupting the signals they carry. Because modern militaries and economies depend heavily on satellites for navigation, communication, surveillance and early warning, ASAT capability is treated as a decisive instrument of space deterrence. India joined this club on 27 March 2019 with Mission Shakti, conducted by the Defence Research and Development Organisation (DRDO) and announced by the Prime Minister, making India the fourth nation with a proven ASAT capability after the United States, Russia and China.
How ASAT Weapons Work — The Main Types
| Type | Mechanism | Debris risk |
|---|---|---|
| Direct-ascent kinetic | Ground-launched missile flies up and physically strikes the satellite (hit-to-kill); does not enter orbit | High |
| Co-orbital kinetic | Interceptor is placed in orbit, then manoeuvres to collide with or grab the target | High |
| Directed energy | Lasers, high-power microwaves or particle beams blind sensors or fry electronics | Low |
| Electronic warfare | Jamming and spoofing disrupt or falsify satellite signals | None |
| Cyber | Attacks on ground stations, data links or onboard systems | None |
Mission Shakti was a direct-ascent kinetic test. The DRDO's Prithvi Defence Vehicle Mark-II (PDV Mk-II) interceptor used hit-to-kill technology to destroy India's own Microsat-R satellite in low Earth orbit at roughly 283 km altitude, completing the intercept in under three minutes.
Significance and the Debris Problem
ASAT capability signals technological maturity in ballistic-missile defence, precision tracking and space situational awareness. However, kinetic tests are condemned for generating orbital debris that lingers for years and can trigger a cascade of collisions known as Kessler syndrome. NASA Administrator Jim Bridenstine called Mission Shakti a "terrible thing," noting it created about 400 pieces of debris, of which roughly 60 were trackable and 24 rose above the apogee of the International Space Station, raising the ISS collision risk by an estimated 44% over 10 days (NASA statement, early April 2019). India argued it deliberately chose a low altitude to ensure debris decayed quickly.
Current Status and Global Governance
There is no treaty specifically banning ASAT weapons. The Outer Space Treaty (1967) prohibits placing weapons of mass destruction in orbit but does not bar conventional ASAT systems. In April 2022 the United States declared a unilateral moratorium on destructive direct-ascent ASAT tests, and on 7 December 2022 the UN General Assembly adopted Resolution A/RES/77/41 calling for such a moratorium — passed with 155 in favour, 9 against and 9 abstentions. Notably, India abstained, consistent with its position as a recent ASAT tester preserving strategic options.
UPSC Angle
Remember the precise facts: DRDO (not ISRO) led the test; the target was in LEO; India is the fourth ASAT power. For Mains, weigh strategic deterrence against space-sustainability costs and the weak international legal framework — and note India's abstention on the 2022 UN resolution as a balance between strategic autonomy and responsible space behaviour.
