To protect people on the ground, NTP spacecraft would not lift-off directly from Earth, Mr. Sheehy, and any NTP design would place the living quarters at the other end of the rocket to the reactor. The distance between the crew and reactor also provides a buffer, says Mr. The liquid propellants, stored between the engine and the crew area, block out radioactive particles, acting as “a tremendously good radiation shield,” he says. This would be mitigated through the rocket’s design, Mr. Shorter missions would limit the crew’s exposure to space radiation, but there is still concern about the radiation emitted from the nuclear reactor inside the spacecraft. This means the technology could get astronauts to Mars and back in less than two years. NTP rockets produce twice the thrust per unit of propellant than a chemical system which is like saying it does “double the miles per gallon,” says Mr. That thermal energy heats a liquid propellant, usually liquid hydrogen, which expands into a gas and is shot out the back end, producing thrust. An NTP system uses a nuclear reactor to generate heat from a uranium fuel. That’s why the space agency is looking to develop nuclear-powered rockets. “The longer you’re out there, the more time there is for stuff to go wrong,” he adds. It would also decrease the overall risk of the mission. This would reduce their exposure to space radiation, which can cause health problems including radiation sickness, increased lifetime risk of cancer, central nervous system effects and degenerative diseases. NASA wants to get there faster, to minimize the crew’s time in outer space, he says. These could get you to Mars, but it would take a long time, says Jeff Sheehy, chief engineer of NASA’s Space Technology Mission Directorate. Most rockets today are powered by chemical engines.
Along enabling human space travel, it could open up space for galactic business opportunities, he adds. “Nuclear technology will expand humanity’s reach beyond low Earth orbit, and into deep space,” he said. Michael Eades, director of engineering at USNC-Tech, says that nuclear-powered rockets would be more powerful and twice as efficient as the chemical engines used today, meaning they could travel further and faster, while burning less fuel. Currently, the shortest possible trip for an unmanned spacecraft is seven months while a crewed mission is expected to take at least nine months.