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)

People pause at a memorial set up for victims of a mass shooting in Las Vegas, Nev., on Tuesday, October 3, 2017. A gunman opened fire on an outdoor music concert on Sunday. It was the deadliest mass shooting in modern U.S. history, with dozens of people killed and hundreds injured, some by gunfire, some during the chaotic escape. (Photo by John Locher/AP Photo)

Lance Cpl. Blas Trevino of the 1st Battalion, 5th Marines, shouts out as he is rescued on a medevac helicopter from the U.S. Army's Task Force Lift “Dust Off”, Charlie Company 1-214 Aviation Regiment after he got shot in the stomach outside Sangin, in the Helmand Province of southern Afghanistan on June 11, 2011. The Army's 'Dust Off' crew needed two attempts to get him out, as they were fired upon and took five rounds of bullets into the tail of their aircraft. (Photo by Anja Niedringhaus/AP Photo/File)

Smoke and flames rise over a warehouse storing ammunition for multiple rocket launcher systems at a military base in the town of Kalynivka in Vinnytsia region, Ukraine September 27, 2017. Ukrainian officials say they have evacuated more than 30,000 people after a fire and ammunition explosions, at the military base on Tuesday. (Photo by Gleb Garanich/Reuters)

Fotos Pole Street Buenos Aires – Miss Pole Dance Argentina 2012. (Photo by Diego Castillo)

English pop singer Shane Fenton, later known as Alvin Stardust, autographing a woman's leg in his dressing room. (Photo by John Pratt/Keystone Features/Getty Images). September 1962

Festivalgoers during the 2018 Coachella Valley Music And Arts Festival at the Empire Polo Field on April 20, 2018 in Indio, California. (Photo by Frazer Harrison/Getty Images for Coachella)

Damselflies covered in dew rest on a wild flower by the Po River, northern Italy on August 15, 2016. (Photo by Alberto Ghizzi Panizza/Barcroft Images)