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 rebel fighter celebrates as his comrades fire a rocket barrage toward the positions of troops loyal to Libyan ruler Muammar Gaddafi April 14, 2011 west of Ajdabiyah, Libya. Rebels exchanged artillery and rocket fire with loyalist troops west of Ajdabiyah April 14 as the confict engulfing Libya continued. (Photo by Chris Hondros/Getty Images)

Visitors watch as Grigory Broverman, a member of the Cryophile winter swimmers club, pours a bucket of cold water over his 6-year-old daughter Liza during a flash mob, part of a celebration of Polar Bear Day at the Royev Ruchey Zoo in a suburb of the Siberian city of Krasnoyarsk, Russia, November 29, 2015. The air temperature was around minus 5 degrees Celsius. (Photo by Ilya Naymushin/Reuters)

Snow covers roofs, streets and the Charles River following a winter blizzard in Boston, Massachusetts January 28, 2015. A powerful blizzard struck Boston and surrounding New England on Tuesday, leaving some 4.5 million people grappling with as much as three feet of snow and coastal flooding. (Photo by Brian Snyder/Reuters)

A 10-year-old pet goldfish named George undergoes veterinarian Tristan Rich's scalpel to remove a life-threatening head tumor in this handout picture taken September 11, 2014 and provided to Reuters by the Lort Smith Animal Hospital in Melbourne, Australia. In a 45-minute long procedure described by Rich as “fiddly”, the fish was sedated by water laced with anaesthetic, the tumour removed and the wound sealed with tissue glue followed by antibiotics and painkillers. (Photo by Reuters/Lort Smith Animal Hospital)

Sun Rongchun, 57, exercises with an improvised cervical traction device attached to a high bar at a sports complex in Shenyang, Liaoning province, China on April 9, 2019. (Photo by Sheng Li/Reuters)

Chile's Mary Dee Vargas (L) reacts after defeating Brazil's Larissa Farias compete in their Judo Women's –48 kg Bronze Medal contest during the Lima 2019 Pan-American Games in Lima on August 8, 2019. (Photo by Guadalupe Pardo/Reuters)

Protesters shout as they hit a pole during ongoing anti-government protests in Beirut, Lebanon on November 19, 2019. (Photo by Andres Martinez Casares/Reuters)