Four years from now, if all goes well, a nuclear-powered rocket engine will launch into space for the first time. The rocket itself will be conventional, but the payload boosted into orbit will be a different matter.
I don’t see much of a difference between this and current technology. NASA has been using nuclear reactors in probes and rovers for quite some time. Presently deep space probes use nuclear reactors to generate electricity. Propulsion is produced by using electricity to accelerate ions. The ions come from gas stored in cold liquid form.
I don’t see any breakthrough technology here. From what I can tell reading the article, it’s just a lightly different way of creating propulsion, pressurizing the gas with heat instead of accelerating it with an electromagnetic field. Seems like a step back actually.
Some satellites and rovers have used Radioisotope Thermoelectric Generators (RTGs), which are very different from a nuclear reactor. They use polonium-210, which generates heat, and that heat is converted to electricity with thermocouples. They are low power and inefficient.
To my knowledge no satellite, with an RTG, has ever used ion propulsion. Few interplanetary satellites have ever even used ion thrusters. Dawn, Hayabusa, and Deep Space 1 are the only I can think of, and they all used solar arrays.
Ion thrusters are super efficient, but produce extremely small amounts of thrust. They aren’t practical for getting large spacecraft to Mars. These proposed nuclear engines produce large thrust while have efficiency somewhere between regular chemical propulsion and ion propulsion.
