Fusion-powered rockets that are only the size of a few refrigerators could one day help propel spacecraft at high speeds to nearby planets or even other stars, a NASA-funded spaceflight company says.
Another use for such fusion rockets is to deflect asteroids that might strike Earth and to build manned bases on the moon and Mars, the researchers say.
Rockets fly by hurling materials known as propellants away from them. Conventional rockets that rely on chemical reactions are not very efficient when it comes to how much thrust they generate, given the amount of propellant they carry, which has led rocket scientists to explore a variety of alternatives over the years.
An option now used in spacecraft is the ion drive, which generates thrust by using electricity to accelerate electrically charged ion propellants. Ion drives are far more efficient than chemical rockets, but are limited by the amount of electricity they can harvest via solar panels or generate using radioactive materials.
Instead of chemical rockets or ion drives, scientists have also suggested using fusion rockets propelled by the same nuclear reactions that power stars. These rockets would not only be efficient, but also generate vast amounts of electricity.
However, so far, no one has built a fusion reactor that generates more energy than it consumes. Moreover, the fusion reactors that are under development are huge, making them difficult to hoist into space.