Russia tests 'satellite catcher'

Russia may be testing a satellite capable of chasing down other orbiting spacecraft, the BBC reports quoting observers as saying.

Such technology could be used for a wide variety of uses, including to repair malfunctioning spacecraft, but also to destroy or disable them.

The Kosmos 2499 satellite separated from the upper stage of its rocket two years ago and then chased it down.

The Russian mission follows similar on-orbit tests this year carried out by the US and China.

Kosmos 2499 was launched on 25 December 2013 as part of a seemingly routine mission to add new Rodnik communications satellites to an existing constellation.

Previous Rodnik launches had carried a trio of spacecraft, but on this occasion a fourth object was released into orbit.

The US military initially classified the object as debris, but in May 2014, the Russian government told the United Nations that the launch had sent four satellites into orbit instead of three.

In the meantime, satellite observers had seen the object using engines to perform a series of unusual maneuvers in space that changed its orbit.

These maneuvers culminated on 9 November with a close approach to part of the rocket that originally launched the satellite into orbit.

According to satellite observer Robert Christy, who has been recording the craft's movements, Kosmos 2499 appears to have got to within a few tens of meters of the inactive Briz-KM rocket stage.

"I think this mission is a test, and you test these things with your own satellites, because if you do it with other peoples' they get upset. The Americans don't want bits of Russian hardware sitting alongside their satellites," Mr Christy told BBC News.

Mr Christy says he predicted this in August, tweeting "Cosmos 2499 - Maybe an inspector satellite? Its most probable target is the Briz-KM that launched it."

A satellite inspector is designed to sneak up on another satellite and photograph it or eavesdrop on its communications. But the same technology could also potentially be used to disable spacecraft - an anti-satellite weapon.

However, explicit testing of such weapons in space is prohibited by international treaties.

"The point is that each side sees the other can do it," said Mr Christy.

But the potential uses of such technology are not solely hostile - it could also be valuable to civilian satellite operators, allowing them to extend the lifetime of high-value assets in space through servicing, re-fuelling or repair on-orbit.

Though the mastery of such systems is highly desirable, it has proven extremely difficult in the past, with several failures.