To boldly vacuum where no Hoover has gone before

That’s the mission of a £100m British-backed spacecraft in a daring bid to clear up space junk — and prevent an astronomical catastrophe

LARGE, tentacle-like robotic arms stretch out across Space and enclose the spent piece of a rocket, hugging it close as both objects hurtle around Earth at ten times the speed of a bullet.

If all goes according to plan, it will prove a lethal embrace.

The four-armed robot will use its own thruster rocket to ‘de- orbit’ and descend towards the Earth, plunging hunter and quarry down into the atmosphere, where they will burn up.

Anti-litter campaigns have never been quite so dramatic as the British-backed initiative unveiled this week — the first serious attempt to start cleaning up the many million pieces of space junk circling our planet in a potentially catastrophic dance.

After considering a range of competing projects that variously include the use of harpoons, nets, foam and glue, the European Space Agency (ESA) has chosen to fund a Swiss company called ClearSpace to carry out a trial run that aims to capture a piece of ESA space junk.

Launched from a satellite 310 miles above Earth, the ClearSpace-1, in effect a ‘tow truck’, will then increase its altitude to that of its target and try to connect.

The company describes the process of tracking and catching the errant junk as its ‘Pac-Man system’, after the popular 1980s arcade game which involved gobbling up dots in a maze. It has also been likened to a vacuum cleaner — but this is ‘vacuuming’ at more than 20,000mph.

We humans are a messy bunch and Space has not been spared our careless tendencies.

Over the past 60 years, 5,450 space launches have created a vast sea of orbiting junk weighing 8,400 tons.

There are obsolete spacecraft, defunct satellites, spent rocket parts, huge momentum flywheels and even nuclear reactor cores.

There is a lot of smaller detritus, too: cameras, gloves, rubbish bags, bolts, a small screwdriver that an astronaut dropped on a space walk 36 years ago, and even a discarded toothbrush.

The ESA — which has received £10 million for the project from the British Government — estimates there are more than 128 million bits of space debris smaller than 1cm (0.4 inches), and 934,000 pieces bigger than that.

The U.S. Air Force is able to track the larger pieces — some 23,000 items — but the location of the rest is anyone’s guess.

The harsh conditions of Space — extreme temperatures and radiation — mean objects break up all the time, while the remaining fuel in rocket parts will eventually explode, producing yet more junk.

Countries such as India and China don’t help. They have destroyed obsolete satellites with missiles because it is cheaper than retrieving them. This makes the debris field even denser and more hazardous. M

OST national space agencies and private companies just leave the satellites up there. Of the 5,000 in orbit, only 1,950 are active.

Technically all these objects are floating in orbit — although ‘floating’ hardly seems the right word to use, given that in low orbit they are circling the Earth at about 21,600mph, or so- called ‘hyper-velocity’.

At that speed, the kinetic energy of minuscule objects means even a speck of paint can crack the window of a space shuttle, while a piece of aluminium not much bigger than a cricket ball would have an impact with the explosive power of 25 sticks of dynamite. (The cataclysmic effects of bigger space debris colliding with a space shuttle were graphically illustrated in the 2013 film Gravity, starring Sandra Bullock and George Clooney.)

Since 1961, there have been nearly 300 recorded collisions, or ‘fragmentation events’, including a 2009 pile-up between a U.S. and a Russian satellite that created thousands of pieces of debris. The International Space Station regularly has to reposition itself to avoid potentially hazardous space junk.

Often, working satellites suddenly ‘go black’ and scientists can only conclude that they have been put out of action by flying debris. The chance of satellites colliding has soared in recent years, and experts wonder if investors will soon give up on Space, believing it too risky.

The problem is so serious that Nasa produces a publication called Orbital Debris Quarterly News to report on the latest collisions and disintegrations.

And the problem is expected to get much worse.

Every year, tens of thousands more satellites are being sent into orbit — the entrepreneur Elon Musk, for instance, wants to launch 42,000 refrigerator- sized craft to provide worldwide internet access — greatly increasing the probability of collisions.

Not only is a lot of the debris impossible to see, but changes in gravitational pull and solar winds mean satellites don’t always follow an unchanging orbit and can suddenly alter course, perhaps into the path of some high- speed junk.

Worse, space navigation — unlike aviation — is barely regulated, so satellite owners have to rely on the U.S. military or even amateur astronomers to alert them if they are on a potential collision course.

In a nightmare scenario known as the Kessler Syndrome, a single collision could set off a chain of them, creating a field of debris so dense that it would be too dangerous to launch anything more into Space for hundreds of years.

Jan Woerner, European Space Agency director general, said this week that the situation cannot be allowed to continue.

‘Imagine how dangerous sailing the high seas would be if all the ships ever lost in history were still drifting on the water,’ he said.

The agency plans to have launched the ClearSpace-1 by 2020 in the estimated £ 100 million project. Known as a ‘chaser’ spacecraft, it will ultimately be targeting satellites. The pilot mission, however, will go after a leftover from an ESA rocket launch in 2013. It weighs about the same as a small satellite and has a simple shape, which should make it easy to grab.

Although returning to Earth’s atmosphere would destroy not only the satellite but the ‘chaser’ craft too, ESA hopes eventually to develop a system by which the robot safely ejects the junk, so the former can be re-used.

ClearSpace says its goal is to create a spacecraft that can manoeuvre in low orbit with ‘a high level of autonomy’. T

HERE is, of course, a financial motivation. According to a recent study, the global market in cleaning up space junk will generate $2.9 billion (£2.2 billion) by 2022.

Britain is at the forefront of the race to vacuum Space. A consortium led by Surrey University has successfully tested a space robot equipped with a harpoon and a net.

Once the debris has been harpooned or ‘ caught’ in the net, the robot unfurls a drag sail to slow its speed and bring it out of orbit to burn up in the Earth’s atmosphere.

Rival Italian researchers are working on a system that involves spraying debris with an expanding foam that increases its area-tomass ratio to the point where it is knocked out of orbit.

Meanwhile, a Japanese company has devised a system to capture debris using magnets, and Singaporean researchers have developed a glue to stick large pieces of junk to a small spacecraft.

Another option is to fit satellites with balloons that could be activated back on Earth, slowing them so they re- enter the atmosphere and burn up.

Some experts argue that space junk need not be destroyed but could be recycled. Satellites, for example, contain valuable components that could be re-used.

Scientists are optimistic, but retrieving debris remains a hugely complicated technical challenge. The space junk is not only travelling at immense speed but will frequently be rotating, which could send the clean-up craft into an uncontrollable spin as soon as it grabs it.

‘ The dynamics in Space are very interesting because if you touch the object on one side it will be dragged away,’ said Holger Krag, head of the ESA’s Space Debris Office. ‘ So you can basically embrace [ encircle] it before you touch it, then you just embrace it close as you dampen the tumbling motion.’

Nothing in virtual zero gravity is ever simple, but at least those operating these particular vacuum cleaners won’t have to worry about changing the bag.