“’We need to develop a much larger vehicle, which would be a sort of Mars colonial transport system, and this would be, we’re talking about rockets on a bigger scale than has ever been done before. It will make the Apollo moon rocket look small,’ said Musk in a recent CBS interview, referring to the 363-foot (110-meter) behemoth that was the Saturn V.”
Currently the United States is building a heavy lift Space Launch System that would initially loft 70 tons to low Earth orbit and eventually 130 tons. What Musk seems to be envisioning is something far greater, however. “Requirements: it has to be big, and it has to be launched frequently to send millions of people and tons of cargo spaceward.”
Musk did not elaborate about what this super rocket would look like or what technology it might contain. However, back in the late 1950s and early 1960s a group of researchers developed a concept of a spacecraft that would be propelled through the use of nuclear bomb detonations under Project Orion. The project was terminated soon after the Nuclear Test Ban Treaty. In any case the problems of nuclear fallout and electromagnetic pulse caused by the detonation of hundreds of nuclear bombs in the Earth’s atmosphere were never resolved.
Certainly a nuclear bomb propelled spacecraft, as large as a World War II battleship, carrying hundreds of colonists, would certainly fit Musk’s vision. One way to make it work might be to build the ship in pieces in Earth orbit, beyond the magnetosphere, and then only use the nuclear bomb drive in deep space. Assembling such a vehicle would take a considerable number of launches of conventional heavy lift rockets and a construction project that would dwarf the International Space Station.