A new skin-tight onesie has been designed to help astronauts on space stations protect their muscles and backs.

Although the effects of weightlessness look fun - doing floating tumble turns around your spaceship, sleeping in a pod, even brushing your teeth with a ball of water - the human body has evolved over millennia to work under the influence of Earth’s gravity. Without it, things go wrong.

Astronauts start to lose muscle tissue and minerals from their bones because there is less pressure on the weight-bearing parts of their body - the legs, hips and spine. Their spines also elongate by up to 7cm, as the discs between the vertebrae are not being pushed downwards, which creates back problems.

To prevent bone and muscle loss, astronauts currently have to exercise for two hours a day while they are in space. But now scientists from the Massachusetts Institute of Technology (MIT), King’s College, London, and the European Space Agency’s Space Medicine Office are working on a special suit that replicates the effects of gravity and counters negative effects to the body.

The suit could play a vital role in any future expeditions to Mars, when space travellers will be without gravity for months on end.

“There is a great risk that we will be too weak to function optimally on the surface of Mars,” said David Green of King’s College, London. “When we replicate that ‘first step for man, giant leap for mankind’ moment on the Martian surface there’s this great risk [that the astronaut could] trip, fall and fracture their hip.”

The sleeveless gravity loading countermeasure skinsuit is made of hundreds of layers of elastic material that squeeze the body but remain comfortable. The suit is tighter near the feet than the head, mimicking the way that gravitational pull works on Earth.

It is hoped that the skin-tight outfit will mean the astronauts have to spend less time exercising. Instead, they will protect their muscles simply by wearing the suit as they go about their everyday tasks.

The suit has so far been tested only on the ground, but it is due to be worn by Danish astronaut Andreas Mogensen during his 10-day mission to the International Space Station (ISS) in September 2015. Tim Peake, the British astronaut, may also get the chance to try it out when he sets off to spend five and a half months on the ISS later that year.

As with many developments in space technology, it may turn out that you don’t have to be an astronaut to benefit. Researchers hope that the technology behind the skinsuit also has the potential to help those here on Earth with lower-back problems or with conditions that cause muscles to atrophy.