![A 2014 publicity poster for NASA’s plans to send humans to an asteroid.](/sites/default/files/styles/large/public/SB1%20Journey%20to%20Mars.jpg?itok=_NCe6UG_)
Journey to Mars
![NASA’s Mariner 2 spacecraft data.](/sites/default/files/styles/large/public/SB4%20Mariner%202%20Data.jpg?itok=E356sSPQ)
Mariner 2 Data
![Viking landers were sterilized with heat.](/sites/default/files/styles/large/public/SB5%20Viking%20Sterilization.jpg?itok=e10Xiqph)
Viking Sterilization
![SpaceX CEO Elon Musk giving President Barack Obama a tour of the SpaceX facility.](/sites/default/files/styles/large/public/SB6%20Obama%20and%20Musk.jpg?itok=EkDavnb_)
President Barack Obama and Elon Musk
![Cosmonaut Alexei Leonov.](/sites/default/files/styles/large/public/SB7%20Alexei%20Leonov.jpg?itok=RdZr5sCH)
Alexei Leonov
![A panoramic image of the Mars Pathfinder mission.](/sites/default/files/styles/large/public/6%20Mars%20Pathfinder.jpg?itok=hjFMgIQk)
Mars Pathfinder
![Jeff Bezos (third from left) and and Lori Garver (fourth from left).](/sites/default/files/styles/large/public/9%20Jeff%20Bezos%20at%20Blue%20Origins.jpg?itok=202-vq60)
Jeff Bezos at Blue Origin
![Elon Musk speaking at a Mars Society Conference.](/sites/default/files/styles/large/public/10%20Elon%20Musk%20and%20the%20Mars%20Society.jpg?itok=-pFXMi4f)
Elon Musk and the Mars Society
![Concept art for a Mars settlement.](/sites/default/files/styles/large/public/12%20Mars%20Settlement.jpg?itok=51KT5LFm)
Mars Settlement
![NASA Administrator Charles Bolden congratulating SpaceX CEO Elon Musk.](/sites/default/files/styles/large/public/18%20Elon%20Musk%20and%20Charles%20Bolden.jpg?itok=vu9fRWEk)
Elon Musk and Charles Bolden
![Astronauts practicing microgravity techniques.](/sites/default/files/styles/large/public/19%20Neutral%20Buoyancy%20Lab.jpg?itok=ISMrpwFR)
Neutral Buoyancy Lab
![Members of the Mars Research Society.](/sites/default/files/styles/large/public/21%20Mars%20Arctic%20Research%20Station.jpg?itok=YlpL-miw)
Mars Arctic Research Station
![The Human Exploration Research Analog at the Johnson Space Center.](/sites/default/files/styles/large/public/22%20Human%20Exploration%20Research%20Analog.jpg?itok=jl0i-tV3)
Human Exploration Research Analog
![The Mars Desert Research Station in Utah.](/sites/default/files/styles/large/public/23%20Mars%20Deseert%20Research%20Station.jpg?itok=jeEFx63u)
Mars Desert Research Station
![Members of the Apollo-14 team.](/sites/default/files/styles/large/public/27%20Craters%20of%20the%20Moon%20National%20Monument.jpg?itok=h8YuC7Xg)
Craters of the Moon National Monument
![Equipment testing in Nevada in 1972.](/sites/default/files/styles/large/public/28%20U.S.%20Geological%20Survey%20and%20NASA%20Test.jpg?itok=BQz8JunP)
U.S. Geological Survey and NASA Test
![First American female astronaut, Sally Ride.](/sites/default/files/styles/large/public/31%20Sally%20Ride.jpg?itok=9cPIrQUW)
Sally Ride
![President George H. W. Bush announcing his Space Exploration Initiative.](/sites/default/files/styles/large/public/32%20Space%20Exploration%20Initiative.jpg?itok=a0CyV2O1)
Space Exploration Initiative
Tourist Attraction
![The Flashline Mars Arctic Research Station crew.](/sites/default/files/styles/large/public/42%20Flashline%20Mars%20Arctic%20Research%20Station%20Surveying.jpg?itok=c-5jaxRC)
Flashline Mars Arctic Research Station Surveying
![The Flashline Mars Arctic Research Station with two crew members.](/sites/default/files/styles/large/public/43%20Flashline%20Mars%20Artic%20Research%20Station%20Surveying.jpg?itok=WLfvSClB)
Flashline Mars Arctic Research Station Habitat and Rover
![NASA and researchers from the Mars Institute and SETI Institute.](/sites/default/files/styles/large/public/44%20Mojave%20Field%20Test.jpg?itok=DphkOiA0)
Mojave Field Test
![Crew members performing operations outside the NASA NEEMO Station.](/sites/default/files/styles/large/public/46%20NEEMO%20Station.jpg?itok=MvGmLI1w)
NEEMO Station
![Crew members of NASA Extreme Environment Mission Operations.](/sites/default/files/styles/large/public/47%20Aquarius%20Reef%20Base.jpg?itok=kg0nprvA)
Extreme Environment Mission Operations
![An astronaut and geologist in Arizona testing a lunar rover.](/sites/default/files/styles/large/public/20%20Desert%20Research%20and%20Technology%20Studies.jpg?itok=SmlLzpko)
Desert Research and Technology Studies
![The Mars 3 was the first spacecraft to land on Mars.](/sites/default/files/styles/large/public/Mars3_lander_vsm.jpg?itok=QkSg7lod)
Mars 3 Lander