Question
we all know that there are conventional propulsion systems like liquid fuel and solid fuel rocket propulsion. I think Ion propulsion is the latest technology in propulsion systems.
I wonder if there is any propulsion system that is based on neuclear energy (reactor). I have come to know that neuclear reactors can produce huge amount of electrical energy for years with little fuel. can't we convert that electrical energy into a form of energy that will propell the space craft continuously. does any that type of system exists?
Thank you in advance.
Answer
Naveen, <br /> <br />This is a very interesting question. The answer is "We do use nuclear power, but not in the way you mean." Back in the 1950's and 1960's, the U.S. government invested a fair amount of money to develop a nuclear reactor-powered rocket engine that could be used to propel spacecraft at great speed. Test of the rockets showed great promise. However, by the mid 1970's, the program (Project NERVA) was finished. Why? Cost was one reason; the necessary technological advances were another. However, even if those had been overcome, it is unlikely that we would have ever seen such a vehicle because of safety concerns. These nuclear reactor-powered rockets used a great deal of uranium/plutonium as a fuel source. If there had been an accident during the launch of the vehicle, it would have spread large amounts of radioactive materail all over the face of the planet. It would have been the kind of disaster that would make the Chernobyl accident look like a walk in the park. <br /> <br />This is not to say that we do not use nuclear energy, or that we might never use nuclear energy. Most of the deep space probes that we have sent (Pioneer's, Voyager's, Galileo, Cassini) use nuclear energy to power their electrical systems. However, they do not have mini nuclear power plants on board. What they do have is a much smaller amount of nuclear material that decays naturally. In the process of doing so, it produces heat, which can be used by a thermoelectric generator to produce electricity. <br /> <br />And one day, we might actually have a nuclear reactor powered space craft. However, if we do, it will be a nuclear fusion reactor, not a nuclear fission reactor. The reason why is that a fusion reactor will use 1) lighter fuels like hydrogen and helium and 2) fuels that are not as radioactive and would not cause a horrible environmental disaster if there were an accident on lift off. To get to a point where we would have such a rocket, though, we need to first create a nuclear fusion reactor here on Earth that works. <br /> <br />To find out more about this, check out this NASA site. <br />http://science.nasa.gov/newhome/headlines/prop12apr99_1.htm <br /> <br />To learn more about Project NERVA, go to <br />http://www.aemann.pwp.blueyonder.co.uk/spacecraft/nerva/nerva.html <br /> http://vrd.askvrd.org/services/answerschema.xml
