Spacecraft Propulsion via Nuclear Power

Watch this video to see NASA Marshall Space Flight Center’s Dr. Kurt Polzin describe concepts for using power generated by a nuclear reactor to propel spacecraft. Doc also describes proposed designs for nuclear powered spacecraft and the challenges of safely deploying these systems.

Transcript

00:00:00 [Music] I'm Kurt poen I am the chief engineer for the space nuclear propulsion project I work at the NASA Marshall space flight center in Huntsville Alabama my role is to oversee the development of nuclear thermal and nuclear electric propulsion concepts for the agency electric propulsion is uh a means of propelling a spacecraft where you use

00:00:34 electricity as the power source the power then is put into the propellant and you can do that a couple different ways one is you can use that energy to heat the gas those are called electrothermal thrusters that's the least efficient way to use my electricity the other is to take my gas and use a little bit of that electricity to ionize it so I form a plasma and from

00:01:00 from there I can apply electric and magnetic fields to directly accelerate the atom to generate thrust those are your general plasma thrusters it is lower thrust that's kind of the trade-off over time thousands of hours of operation that doesn't matter and I can do some really great missions with it but I do have to take that into account when I'm planning my mission

00:01:22 especially when you start talking about doing uh missions that involve people because now I have a constraint where I might want to get there at a certain amount of time and that does prove to be a challenge for plasma thrusters the electric propulsion system needs power um most of everything that's flown now is solar uh but if you want to go further out or if you want to do

00:01:46 human missions say to Mars which is what we're working on now uh you need lots of power in space and that pushes you away from solar into nuclear the kind that that we're really focused on at the agency now which is fion based this is taking uranium like you having a nuclear power plant on the ground and you fion it to create a bunch of fision fragments but also release a

00:02:12 certain amount of power of of energy per fision event much more power dense than radioisotope more controllable because I can adjust how many fions are occurring at any one time and then I take that energy which is thermal and I can convert it to power just like I do on the earth we're talking about something for space nuclear propulsion right now that's megawatts the reactor itself for

00:02:37 a couple megawatts of electric power is only about the size of a large trash can mean it's not very big because you've got so much energy stored in those atoms that confusion up until recently those reactors have been built using what's called hu or highly enriched uranium so it's the same type that you would find in nuclear warheads and that's not good right because if that goes missing

00:03:03 you've got big problems with proliferation regulatory environments especially when it comes to nuclear have kept people out of the game recently there's been a big push to try things with something called Le or low enriched uranium below 20% enrichment the proliferation risk is not nearly as big I go to lower enrichment more organizations have that license the

00:03:28 barrier to getting that license license is a lot lower so the cost is a lot lower it allows me to engage a lot more of the nation's industrial base intellectual base and this is where there's been a big growth because nuclear is so clean and so self-contained and so self-sufficient and it runs for such a long period of time that's all been kind of enabled by

00:03:52 going to this low enriched uranium I've got multiple ideas now starting to be brought to the Forefront they're different and I like like that because not any one person has all of the answers so you're really looking for this period of growth and invention and Discovery to really see which ideas are the best which ones percolate to the top and I think that's great right because

00:04:16 we're going to benefit from that