Circling high above us in space, a mysterious object is being tracked by the US military. The strange object, which has been entitled Object 2014-28E, was secretly launched in May by the Russian military, but nobody knows its purpose and so far Moscow’s ministry of defence is remaining tight-lipped.

2014-28E first came to the attention of the world when it was sighted recently by amateur astronomers. It was initially thought to be space debris originally sent into space by Russia to add communication satellites to existing military space hardware, but its behavior has since been so unorthodox that there are now concerns that it could form part of a more sinister plan, concerns fuelled by the fact that Russia did not declare its launch.

Astronomers have watched 2014-28E guide itself towards other Russian space objects, and then reconnect with the remains of the rocket stage that launched it.The US military is now tracking the object with increasing interest amidst fears that Russia may be reviving its old "satellite killer" programme, originally formed in the late 1980s. This type of "anti-satellite" technology has continued to be developed, with such programmes also being progressed by the US, China and Israel.

Russia has previously declared that it may once again pursue this type of project; in 2010, the head of Russia’s space agency announced that inspection and strike satellites were on its list of future plans. The US military is now tracking Object 2014-28E under the Norad designation 39765, but so far have been unable to determine its mission.

Some theories suggest that it could have been launched as part of a long term plan to build a new Russian high-altitude orbital space station in 2017, a venture that would rival the International Space Station (ISS). This would allow Moscow to become independent of the ISS after 2020: Deputy Prime Minister Dmitry Rogozin said earlier this year: "There are rumours about Russia leaving the ISS project. We will not, the program is set to run until 2020 and we will stick to our international obligations. As for prolonging it till 2024 – that’s what we’re really doubtful of."

The primary concern, however, is whether this piece of secret Russian space hardware is any form of threat to other space installations. Though it is not yet clear whether Object 2014-28E falls into this territory, for defense strategists, the potential weaponisation of space is a growing concern.

Patricia Lewis, space security expert and research director at London-based think tank Chatham House, admitted "I have no idea what it is!"

"Whatever it is, [Object 2014-28E] looks experimental. It could have a number of functions, some civilian and some military.

"One possibility is for some kind of grabber bar. Another would be kinetic pellets which shoot out at another satellite. Or possibly there could be a satellite-to-satellite cyber attack or jamming.

"It would be odd if space were to remain the one area that [militaries] don’t get their hands on."

Until its mission becomes clear, Object 2014-28E will continue to attract attention from the US military and other national security organisations across the globe.