Knowledge of the past and an optimistic view of the present give you great opportunities.
Buzz AldrinHaving walked on the Moon, I know something about what we need to explore, really explore, in space.
Buzz AldrinThe energy varies with the square of the velocity, so if you need five times the velocity, that's 25 times the energy.
Buzz AldrinTo send humans back to the moon would not be advancing. It would be more than 50 years after the first moon landing when we got there, and we'd probably be welcomed by the Chinese. But we should return to the moon without astronauts and build, with robots, an international lunar base, so that we know how to build a base on Mars robotically.
Buzz Aldrin