Robert Zubrin (born April 9, 1952) is an American
aerospace engineer and author, best known for his advocacy of the manned exploration of
Mars. He and his colleague at Martin Marietta, David Baker, were the driving force behind
Mars Direct, a proposal intended to produce significant reductions in the cost and complexity of such a mission. The key idea was to use the
Martian atmosphere to produce oxygen, water, and
rocket propellant for the surface stay and return journey. A modified version of the plan was subsequently adopted by
NASA as their "design reference mission". He questions the delay and cost-to-benefit ratio of first establishing a base or outpost on an asteroid or another
Project Apollo-like return to the Moon, as neither would be able to provide all of its own oxygen, water, or energy; these resources are producible on Mars, and he expects people would be there thereafter.