New life for nukes in space

Saving money on space payloads to be sent to the moon is the key to success

A vision of nuclear propulsion to send humans to the planets is taking shape on the high desert of the Snake River plain in eastern Idaho even though there is no spaceport here. A design from the 1960s to send space payloads to the Moon, Mars, and beyond using a nuclear reactor is being updated with new ideas and technologies. Stephen Howe, Director of the Center for Space Nuclear Research (CNSR), in Idaho Falls, ID, says his updated design ideas could, if implemented, carry an additional eight tons of payload on a mission to send astronauts to the Moon.

If you are thinking in terms of moving coal or grain along the Mississippi in a river barge, eight tons is a sneeze in the scheme of things. However, in the rocket ship business, where payloads are measured by the pound, and with costs at liftoff measured in the tens of thousands of dollars per pound of payload, eight tons is a very big number. Howe and his team are getting some attention for his Center's R&D program which is located at the Idaho National Laboratory (INL).

Speaking at the Space Nuclear Conference held in Boston in June, Howe described the new technology as old ideas with updated designs. The NERVA program, which ended in 1972, used a fission reactor to heat up hydrogen and blast it out the thrust end of the rocket. The benefit is lots more propulsion with the nuclear rocket for the same amount of fuel used by a chemical rocket. NERVA was not successful for technical and political reasons. This history doesn't deter Howe who says new R&D will overcome the technical issues and, he adds, the rocket would only be fired outside of earth's atmosphere thus perhaps tempering some of the political reactions to using nukes in space.

Howe points out the higher propulsion power of a nuclear rocket for a mission to the Moon would reduce the number of launches needed to support it and save billions of dollars. According to Howe's calculations, the 250 tons of payloads needed to support a sustained presence on the Moon could be delivered with nine nuclear rockets compared to 12 chemical rockets. At $1.5B per launch three fewer launches would save $4.5B. To paraphrase the famous words of Everett Dirkson, that's real money. Put another way, if Howe's research pans out, a nuclear rocket will be a bargain compared to chemical rockets.

One of the barriers to nuclear rockets is that there is still significant opposition to the use of nukes in space despite the successful track record of NASA's Cassini probe to Saturn and the New Horizons mission to Pluto. Both of these missions used radioisotope thermal generators (RTGs) to make electricity for the deep space probes which cannot use solar power past the orbit of Mars. NASA experts points out Howe's rockets would only work outside the Earth's atmosphere. Astronauts on-board would face higher risks from cosmic radiation than they would from the nuclear rocket.

The prospect of saving billions in costs to set up and supply a moon base has got to be attractive to NASA. So while it is true there is no space port in Idaho, Howe has an idea for a new, nuclear rocket that just might fly.