India had A-SAT capability in 2007 but lacked political will: Ex-ISRO chairman on 'Mission Shakti'

Nair said the DRDO had anti-missile technology, including the algorithms required for setting the trajectory to hit the moving target.

"Marrying the two technologies (of ISRO and DRDO) was required which happened over the last few years," Nair told PTI.

He said it would have taken about two years for scientists to perfect the missile launch once the go-ahead for the test was given by the government. 

Asked if India could have demonstrated the anti-satellite missile capability in 2007 itself, Nair said "certainly", but it could not be done due to absence of "political decision" to go ahead with it at that time.

"Now, Modiji has courageously taken the decision," he said. The prime minister on Wednesday announced India had demonstrated the capability by shooting down a live satellite, describing it as a rare achievement that puts the country in an exclusive club of space superpowers.

"...now (Prime Minister Narendra) Modiji has taken the initiative and he had the political will and courage to say that we will do this. We have now demonstrated this to whole world," Nair told PTI.

Dr VK Saraswat, former of the Defence Research and Development Organisation (DRDO), also expressed similar sentiments and said they did not get a positive response from the UPA government. 

"We made presentations to National Security Adviser and National Security Council when such discussions were held, they were heard by all concerned, unfortunately, we didn't get positive response (from UPA), so we didn't go ahead," Saraswat said. 

"When the proposal was put up by Dr Satheesh Reddy (current DRDO Chairman) and NSA Ajit Doval to PM Modi, he had the courage and based on that he gave a go ahead. If the clearances were given in 2012-13, I'm quite certain that the launch would have happened in 2014-15," he said. 

Experts said India has possessed the anti-missile technology for several years but needed the political go-ahead to actually test it in live conditions. They said the Defence Research Development Organisation (DRDO) received the green signal to prepare for the test two years ago, which came to fruition on Wednesday.

In 2012, India conducted simulated tests, establishing the capability but the then Manmohan Singh-led UPA government had not given permission for a live test, likely over concerns that a destroyed satellite would result in debris that would damage satellites of other countries.

India is only the fourth country to acquire such a specialised and modern capability after the US, Russia and China. There has been no instance of a space war but the countries have demonstrated their capabilities by testing on their own satellites, like India did on Wednesday.

The United Nations Institute for Disarmament Research (UNIDIR) defines A-SAT (Anti-Satellite) as "any capabilities aimed at destroying or disabling space assets for any reason, whether military or civilian, offensive or defensive". 

Following the announcement, experts said the anti-satellite missile capability will be a deterrent in the event of a war where space may be the theatre of action with countries seeking to down enemy satellites.

The United Nations Institute for Disarmament Research (UNIDIR) defines A-SAT (Anti-Satellite) as "any capabilities aimed at destroying or disabling space assets for any reason, whether military or civilian, offensive or defensive". 

In 2007, China destroyed its FengYun 1C weather satellite with an SC-19 missile, leaving behind space debris consisting of 3,280 pieces of trackable debris, as well as up to 32,000 pieces that are non-trackable.

The following year, during Operation Burnt Frost, the US destroyed its own satellite, USA-193, with an SM-3 interceptor creating 174 pieces of trackable debris, plus non-trackable shards. 

Now, the spectre of space war has spilled over from the realm of Hollywood fiction into Indian reality.