NASA says it could be another 20 years before humans touch down on Mars, but in a sense, the Mars Society has been exploring the red planet for more than a decade – in Utah. Photo: Csilla Orgel, a geologist of Crew 125 EuroMoonMars B mission, makes her way back to the Mars Desert Research Station (MDRS) in the Utah desert March 3, 2013. The MDRS aims to investigate the feasibility of a human exploration of Mars and uses the Utah desert's Mars-like terrain to simulate working conditions on the red planet. Scientists, students and enthusiasts work together developing field tactics and studying the terrain. All outdoor exploration is done wearing simulated spacesuits and carrying air supply packs and crews live together in a small communication base with limited amounts of electricity, food, oxygen and water. Everything needed to survive must be produced, fixed and replaced on site. (Photo by Jim Urquhart/Reuters)

A Sorb egg painter decorates an Easter egg while using bent spoons full of melted wax as coloring at the annual Easter egg market on March 16, 2013 in Schleife, Germany. Easter is a particularly important time of year for Sorbs, a Slavic minority in eastern Germany, and the period includes the tradition of painting Easter eggs that include visual elements intended to ward off evil. Many Sorbs still speak Sorbian, a language closely related to Polish and Czech. (Photo by Adam Berry)

A demonstrator holds up a picture depicting Russian President Vladimir Putin with make-up, during a protest by the gay community in Amsterdam April 8, 2013. Russia does not discriminate against homosexuals, Putin told reporters in Amsterdam on Monday where he was greeted by gay rights and other activists critical of Russia's track record. Putin is on one-day visit in the Netherlands for the start of the Netherlands-Russia Year. (Photo by Cris Toala Olivares/Reuters)

A girl joins other novice nuns for a lunch at the Sathira-Dhammasathan Buddhist meditation centre in Bangkok April 21, 2013. A group of Thai girls are choosing to spend part of their school holidays as Buddhist nuns, down to having their heads shaven at the meditation centre. The centre, founded in 1987, is a learning community for peace and harmony that has programs open to people regardless of age and gender. (Photo by Damir Sagolj/Reuters)

In this Sunday, April 28, 2013 photograph, people watch as Indian Sailendra Nath Roy attempts to cross Teesta river suspended from a zip wire attached to his ponytail moments before his death in Siliguri, West Bengal state, India. Roy who was named a Guinness World Record holder in 2011 for travelling the farthest distance on a zip wire using hair died during the stunt Sunday when he suffered a heart attack. (Photo by AP Photo)

A German contestant adjusts his helmet during the “Battle of Nations” in Aigues-Mortes, southern France, Friday, May 10, 2013 where Middle Ages fans attend the historical medieval battle competition. The championship will be attended by 22 national teams, which is twice the number it was last year. The battle lasts until May 12. (Photo by Philippe Farjon/AP Photo)

A five meters high sculpture “Pentateuque” created by Contemporary French artist Fabien Merelle, is displayed in Central, business district of Hong Kong, Tuesday, May 21, 2013. The artwork brings to real life the fantastical and seemingly impossible act of an average man balancing a gigantic elephant. The elephant and the man are modeled on one at the Singapore Zoo and on the artist himself. (Photo by Kin Cheung/AP Photo)

A demonstrator waves Turkey's national flag as he sits on a monument during a protest against Turkey's Prime Minister Tayyip Erdogan and his ruling AK Party in central Ankara June 2, 2013. Erdogan accused Turkey's main secular opposition party on Sunday of stirring a wave of anti-government protests, as tens of thousands regrouped in Istanbul and Ankara after a lull and trouble flared again in the capital. Police used tear gas on protesters in Ankara but the clashes were relatively minor compared with major violence in Turkey's biggest cities on the previous two days. (Photo by Umit Bektas/Reuters)