Currently the amount of time astronauts can spend in space is limited because of fears that space radiation causes cancer. Many crew members also need glasses after returning from space because the effects of micro-gravity causes pressure to build up in the optic nerve. There are also fears that astronauts could develop dementia or suffer fertility problems.

The first experiments away from the ISS will take place in cislunar space – the area of space around the Moon – before missions begin venturing further afield.

The final step will see human missions sent into Mars’ orbit or one of its moons, before crews eventually land on the Martian surface and set up colonies using modular architecture and 3-D printing.

“NASA is closer to sending American astronauts to Mars than at any point in our history,” said NASA Administrator Charles Bolden.

“Today, we are publishing additional details about our journey to Mars plan and how we are aligning all of our work in support of this goal. In the coming weeks, I look forward to continuing to discuss the details of our plan with members of Congress, as well as our commercial and our international and partners, many of whom will be attending the International Astronautical Congress next week.”