"[4] He and his colleague at Martin Marietta, David Baker, were the driving force behind Mars Direct, a proposal in a 1990 research paper 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.

He questions the delay and cost-to-benefit ratio of first establishing a base or outpost on an asteroid or another Apollo program-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.

[8][circular reference][9] He has developed a number of concepts for space propulsion and exploration, and is the author of over 200 technical and non-technical papers and several books.

He was also "a senior engineer with the Martin Marietta Astronautics company, working as one of its leaders in development of advanced concepts for interplanetary missions".

[12] In his book, Entering Space: Creating a Spacefaring Civilization, Zubrin would write about how both large aerospace firms, and the US Government, would fail to reduce the costs of spaceflight.

For example, a written account of some of these debates is available in On to Mars: Colonizing a New World, as a joint article, "Do indigenous Martian bacteria have precedence over human exploration?"

177–182) An aged Robert Zubrin also appears as a background character in The Martian Race (1999) by Gregory Benford, a science fiction novel depicting early human explorers on Mars in the very near future.

[19] In 2010 Robert Zubrin was featured in the Symphony of Science video "The Case for Mars" along with Carl Sagan, Brian Cox, and Penelope Boston.