Ever since Sputnik first beeped its way around a stunned world, space has been a largely peaceful endeavour. But in the background, the threat of war from above – the ultimate military high ground – has coloured the huge technological advances.

Today the world economies, telephones, TVs and navigators are utterly dependent on the hundreds of orbiting bundles of electronics above our heads.

Those who seek to keep the world’s militaries out of space have had a hard time, yet it is only recently that the spectre of offensive weapons being tested on orbiting satellites has become a hot topic.

In the last 18 months, the Chinese and the US have demonstrated their abilities to shoot down their own satellites. Both tests were greeted with dismay in some parts, and delight in others.

And many international observers have hinted at the real possibility of an arms race in space that could jeopardize the safety of all satellites – even the ones through which you might listen to this programme.

Do weapons in space constitute a new and reckless use of valuable international real estate, or are they a legitimate defence of the world’s most vulnerable technology?

Sue Nelson is joined by three experts to discuss the legal and technological implications:

Ben Basely-Walker is a legal and policy consultant at the Secure World Foundation – a US-based think tank that wants to strengthen global security via an international cooperative system.

Dr Will Marshall is a NASA space scientist but also Science and Security Fellow at the George Washington University Space Policy Institute, and a researcher for the Space Securities Index, an annual review on all space military activities.

Duncan Lennox is the editor of Jane’s Strategic Weapon Systems, which analyses all offensive and defensive weapons systems either in use or under development. Show less