Trips to Mars - on Earth

Here on the slopes of the volcano Mauna Loa on Hawaii, a Mars simulated test "journey" will begin on August 28. For a whole year, six people will live in a dome-shaped tent - surrounded by nothing more than rocks.

German physicist Christiane Heinicke is part of the mission, called HI-SEAS 4. The project, funded by NASA, simulates a research trip to Mars and consists of several missions using different crews. Its aim is to find out how interpersonal problems might affect the performance of future astronauts. In other words: can they get to Mars without killing each other first?

Heinicke and five other scientists from the US and Europe will move into this tent, which is about 11 meters, or 35 feet, in diameter. Twice a week, the crew will don fake space suits to do simulated field tasks, such taking rock samples. For the rest of the week, they'll stay inside, communicating with the outside world via e-mail and recorded messages.

The Mauna Loa volcano is perfect for a simulated journey to Mars (pictured here), according to scientists from the University of Hawaii. Both have very limited plant life, almost no animal life, similar geology, and you can't even see the ocean.

Flying to Mars takes at least eight months, and that's just one way. That's why scientists want to be well prepared for a future Mars mission, and how such a long trip might affect the astronauts. How do people cope with isolation? Or with conflicts that arise? Researchers are particularly concerned that Mars astronauts might develop depression or lethargy.

The Mars 500 study conducted in Moscow in 2010-2011 simulated a complete mission to Mars, including a return flight. It lasted 520 days - longer than any other isolation study. Some of the astronauts invovled developed mild depression due to the unnatural day/night cycle.

Things were a bit different for participants in the Amadee-15 study, who traveled to their fake Mars habitat... by gondola. The two-week simulation project took place on a glacier in the Austrian Alps during summer, when the area, with its debris and masses of ice, is quite impassable - just like the rocky surface on Mars. The team also got to test out Mars rovers.

Mars Society, a space advocacy non-profit, has erected three Mars surface exploration habitats for running analogues. One of them, the Mars Desert Research Station, is in the desert of the state of Utah in the US. A fourth habitat is planned for South Australia, north of Adelaide.

Mars is dead, cold and extremely isolated - a bit like Antarctica. That's why Mars journey simulations are also happening at the French-Italian Concordia Research Station on the Antarctic Plateau. Life is hard there, especially during the dark winter. Researchers investigated the effects of confinement and isolation on participants' stress levels, circadian rhythms and sleep disruption.

Without technology, people cannot live on Mars. Or underwater. So why not simulate a Mars mission far away from breathable air in the ocean? NASA's Extreme Environment Mission Operations takes place at the Aquarius underwater research station off Key Largo, Florida, 19 meters (62 feet) below the surface. Scientists spend up to three weeks at a time there.

Apart from Mars journey simulations, researchers are investigating the complications that would result not only from flying to Mars, but from living there too. Envihab, for example, a medical research facility at the German Aerospace Center, is currently investigating how conditions on other planets might impact the human body.

Nothign grows on Mars. So what will astronauts eat? Researchers at Envihab are experimenting with plants to find out which of them can be grown easily in glass jars, and thus nourish future Mars visitors. Tomatoes could do.

And to Mars we... go? The world's leading space nations are locked in something of a bureaucratic footrace to be the first to get there - likely by 2030 or 2035. Meanwhile, their nimbler, privately financed counterparts (e.g. SpaceX, Mars One) have far more optimistic timeframes, but little to show for it. For now, scientists will have to stick to Mars habitats on Earth. And wait.