“You need propellants to accelerate toward Mars, then to decelerate at Mars, again to re-accelerate from Mars to Earth, and finally to decelerate back at Earth. Accordingly, the mass of these required propellants, in short, drives our need for innovative launch vehicles.”

American former astronaut, aeronautical engineer, and fighter pilot

Buzz Aldrin is an American former astronaut, aeronautical engineer, and fighter pilot. He is known for being the second person to walk on the Moon, following mission commander Neil Armstrong. Aldrin served as the pilot of NASA’s Gemini 12 mission in 1966, during which he made three spacewalks. He later flew as the Lunar Module Eagle pilot on Apollo 11 in 1969. He is now the last surviving member of that crew and the oldest living astronaut.