Detect harmful radiation, pilot a rover module, learn better sleep and body maintenance: astronauts aboard the International Space Station are preparing for future missions even further afield—from the Moon to, one day, Mars.

The latest arrival of four more astronauts to the ISS, due to blast off aboard a SpaceX rocket from Florida on Thursday, will open the door for new experiments aimed at priming humans for long-distance space travel.

"We're trying out technologies for exploration," said Remi Canton, director of Cadmos, the division of France's National Centre for Space Studies (CNES) undertaking 12 new experiments.

Whether it is humans revisiting the Moon for the first time since 1972 or eventually travelling as far as the Red Planet, the challenges are overwhelming.

Firstly, how can engineers ensure that astronauts and their equipment are protected from the flow of particles thrown out by solar storms and cosmic rays?

In two decades orbiting the Earth the International Space Station has become a cutting-edge cosmic laboratory, with astronauts researching everything from black holes to disease and even gardening in microgravity.

The ISS, which orbits about 250 miles above Earth, is as large as a football field inside and divided up like a beehive into spaces where the crew can carry out experiments with guidance from researchers on the ground.

Often, the astronauts are also the guinea pigs.

More than 3,000 scientific tests have been carried out at the ISS since its manned missions began in 2000.

"From a science perspective, there have been some major discoveries," said Robert Pearlman, space historian and co-author of "Space Stations: The Art, Science, and Reality of Working in Space".

Astronauts who spend extended time in space face stressors such as isolation, confinement, lack of privacy, altered light-dark cycles, monotony and separation from family. Interestingly, so do people who work at international research stations in Antarctica, where the extreme environment is characterized by numerous stressors that mirror those present during long-duration space exploration.

To better understand the psychological hurdles faced by astronauts, University of Houston professor of psychology Candice Alfano and her team developed the Mental Health Checklist (MHCL), a self-reporting instrument for detecting mental health changes in isolated, confined, extreme (ICE) environments. The team used the MHCL to study psychological changes at two Antarctic stations. The findings are published in Acta Astronautica.

"We observed significant changes in psychological functioning, but patterns of change for specific aspects of mental health differed. The most marked alterations were observed for positive emotions such that we saw continuous declines from the start to the end of the mission, without evidence of a 'bounce-back effect' as participants were preparing to return home," reports Alfano.