To get an idea of the energy involved in a rocket launch, the NASA Saturn V, moon rocket, fully fueled on the launch pad contained the chemical energy of 2,000 pounds of TNT. This old technology could carry us to Mars and back on missions that would last years. To cut the mission time, the risks, and the mass of supplies required for such a prolonged space mission NASA is looking at alternative means of rocket propulsion. Back in the 1950s NASA's project Orion was a study to investigate propelling a rocket by a series of atomic bomb explosions behind the vehicle. Now a safer and more gentle way of propelling a space craft with nuclear fission is being studied as the result of a NASA grant to BWX Technologies. The concept is to heat liquid hydrogen using a high temperature fission reactor furnace which would expel the gas at a high velocity producing the rocket's thrust. The process would be about twice as efficient in terms of thrust per pound of fuel when compared to burning a hydrogen and oxygen mixture. Since it is unacceptable to release trace amounts of radioactivity in the rocket's exhaust, engineers are investigating a technique developed by NASA in which the hydrogen exhaust is burned with oxygen to produce water which can be caught and decontaminated. Don't expect to buy a round trip ticket on a high speed fission powered rocket any time soon. However, in the long run nuclear technology could revolutionize the exploration and colonization of our solar system.