Ballistic Missile Defence (BMD) Interceptor missile being launched by Defence Research and Development Organisation (DRDO) in an Anti-Satellite (A-SAT) missile test ‘Mission Shakti’ engaging an Indian orbiting target satellite in Low Earth Orbit (LEO) in a ‘Hit to Kill’ mode from Abdul Kalam Island, Odisha, Wednesday, March 27, 2019. With this India joins a select group of four nations, which have such capability

India's success in demonstrating the anti-satellite (ASAT) capability came after nearly two decades of painstaking research by Indian defence scientists to put in place a ballistic missile defence system that supplied the building blocks for the ASAT.

The development of the BMD – a missile shield - began in the late 1990s with the objective of creating two types of interceptors that can hit an enemy missile at an altitude of about 50-80 km outside the atmosphere (Exo-atmospheric) and within the atmosphere at a height of 30 km (Endo-atmospheric).

The result was Prithvi Air Defence (PAD) and Advanced Air Defence (AAD) interceptors, developed under the watchful eyes of then Defence Research and Development Organisation (DRDO) chief V K Saraswat and his successor Avinash Chander.

PAD's first test in November 2006 was a success. Within two months, China shocked the world with the announcement of its own ASAT, compelling India to step up on the gas.

While the components of the indigenous BMD are still being put in place for an effective missile shield, government officials on Wednesday said DRDO’s BMD interceptor was used to hit the target satellite in the ASAT program.

Even though there are ways to demonstrate ASAT capabilities like "fly-by tests” and jamming, there's no clear answer on why the government allowed a trial of the 'kinetic kill' technology.

“This is a technology where we have developed the capability. Space technologies are constantly evolving. We have used the technology that is appropriate to achieve the objectives set out in this mission,” officials said responding to the query.

DRDO scientists said targeting a satellite in a low-earth orbit is an easy job for an interceptor missile because the satellite has zero manoeuvrability and plenty of time is available to study the satellite to know its parameters so that the target can be accurately plotted in the kill vehicle. “It's a benign target,” said a former DRDO scientist.

Technology wise ASAT is not something really very new. Russia, China and the USA had several projects involving terrestrially based missiles hitting out at the satellite payloads. As early as in the 1980s, the USA launched missiles from an F-15 fighter jet with that objective.