We begin today with nuclear power in space. The idea of a nuclear-powered spacecraft goes back decades. Now it may become reality. The Defense Advanced Research Projects Agency, DARPA, and NASA are teaming up on a demonstration project. They want to see if a nuclear rocket engine could power flight to Mars. NASA program manager Dr. Anthony Calomino spoke to Federal News Network’s Tom Temin about the project.
Tom Temin So we’re talking about nuclear for propulsion and not nuclear to, like keep the astronauts alive with electricity and to run the microwave oven inside there.
Anthony Calomino Yeah. So. So the DRACO mission that we’re partnering with DARPA on is actually a propulsion system is that really is all that it will do is provide thrust to the vehicle.
Tom Temin And is this thrust that would take it out of Earth into space or would it kick in once the vehicle is in space?
Anthony Calomino So we would actually place the vehicle itself, the nuclear thermal rocket. We would actually place it into orbit around Earth using chemical systems, traditional chemical systems. And then once it is in orbit, a safe orbit around Earth, thousands of kilometers away, that’s when we would conduct the experiment. The nuclear part.
Tom Temin Because the levels of thrust needed to maneuver in space or infinitesimal. Right. Compared to what it takes to get it up and out into space from Earth.
Anthony Calomino It certainly is a small fraction. Once you’re in space, you need a small fraction of the force that it took, actually get the hardware and the mass into space to move around. Yes.
Tom Temin And before we get into some of the details in between for this craft to come back from Mars, I don’t know what the gravitational pull on Mars is, but would this be able to get it out of Mars and back into reentry here?
Anthony Calomino So I just want to make clear that the mission that we’re talking about with DRACO would just be a an in-space near earth demonstration. You know, it wouldn’t be anything what we would call as an operational vehicle. It would just be a proof of demonstration of the technology itself. When we get to an operational vehicle, something that we would want to use for Mars, the nice thing about NTP is it provides us high thrust, you know, so we can generate, you know, up to anywhere from 25,000 up to 75,000 pounds of thrust from that engine. And that’s the kinds of force that you would need to leave Earth, we call Earth departure and get on to a trajectory that would that would give you the sufficient velocity or energy to get to Mars.
Tom Temin And you’ve mentioned the DRACO project with DARPA. That’s demonstration Rocket for Agile Cislunar Operations. Cislunar meaning what?
Anthony Calomino Cislunar means the space between Earth and the Moon is really the way that you could think of. It extends a little bit beyond the moon, but it is certainly the space that that is around Earth and the Moon.
Tom Temin And just in layman’s terms, how would this rocket engine work? Because you think of nuclear power as generating heat and then that he heats up water to produce steam or something like that. How would this work? You’ve got a nuclear reactor then. Then what?
Anthony Calomino It uses some of the very similar principles that you just spoke to. It’s actually it’s an incredibly simple system. It is the reactor which is used as a heat or thermal energy source. So it heats up hydrogen propellant that flows through it. And then we use the heated hydrogen propellant through an exhaust nozzle to move the vehicle forward. And so the reactor is really the energy source for propulsion.
Tom Temin And it would heat up hydrogen and shoot it out a nozzle.
Anthony Calomino Yes. And push it out a nozzle.
Tom Temin What are the chief difficulties of this? Is it simply that people worry what could happen with a nuclear source if something went wrong with it and then you’d have a bad problem.
Anthony Calomino So, you know, we could talk about the safety of of the nuclear aspect to the design. We actually are using quite a bit of knowledge that’s been gained with terrestrial systems on how to manage fuel and how to manage the temperatures of those fuels and keep systems safe. And we’re going to implement that in these systems as well. The real challenge for the NTP system is the reactor, but it’s not the nuclear aspects of the reactor so much as it is the the high temperatures that that reactor is going to operate. And so, you know, eventually NASA would want to have a reactor that can operate at 2,700 or 2,800 degrees Celsius. And so that puts a lot of strain and stress on the materials and that becomes the big challenges is picking the right materials that work for that application and making sure hat they survive the function.
Tom Temin We’re speaking with Dr. Anthony Calomino. He’s a program manager and a materials and structures engineer at NASA headquarters. Is there lessons learned for this from, say, the Navy’s experience in nuclear submarines?
Anthony Calomino Lessons learned with with you know, it’s not just the Navy reactors. It’s all of the reactors. But certainly the Navy has a lot of safety protocols and safety procedures in the way that they operate those nuclear reactors. And we do have associations and subject matter experts that we’ve talked to and work with on that to make certain that we implement their practices where it makes sense and we utilize their lessons learned on base systems.
Tom Temin Of course, they’re surrounded by cold water that could be, I guess, pumped in to cool things off if need be. Not the case in Cislunar space.
Anthony Calomino Yeah, not the case in Cislunar space. But one nice thing about being in Cislunar space is that you’re outside of the biosphere of Earth. And again, these systems are going to be very safe. We have no reason to believe that there would be a problem. But the one nice thing about it is that the consequences of something should happen is very, very small for Earth itself.
Tom Temin Right. And of course, you’ll be testing it without anybody aboard.
Anthony Calomino Right. The first few instances of this, there will be autonomous vehicles that will be tested without any life form on board.
Tom Temin And tell us about the programmatic aspects of this. What is DARPA bringing to it? What is NASA bringing to it and when will we see something try it out?
Anthony Calomino So NASA’s responsibilities is really on the key thing that we have the you know, the strong technical interest in which is the engine itself. Right. The the reactor design, the reactor operation and all of the turbo machinery that needs to wrap around that to make it an integrated engine and assemble, taking responsibility to manage in and fund that activity. That would really be the core of what we would want to use for some of our missions. DARPA will be taking the responsibility for the overall integrated vehicle that we’ve demonstrated. There’s cryo fluids that need to be designed and placed into that vehicle. Actually, the mission conops the launch requirements to to safely launch it from Earth. And those would be the responsibilities for DARPA on the mission.
Tom Temin So it will go up. This engine will have a some kind of a simulated craft, not simulated, but a model type of craft that it’s attached to. And how will that whole thing get up into space in the first place?
Anthony Calomino So the entire vehicle, space vehicle will actually be assembled on Earth. It’s, you know, relatively small by, you know, launch payload standards, relatively low mass system. Those aren’t really constraints in terms of what we’re doing. So we would launch an integrated system that would be ready to be essentially turned on and operated. It would include all the craft load tanks, all of the avionics, all the controls, including the engine on it to demonstrate.
Tom Temin And this is something I’m thinking minivan sized type of thing.
Anthony Calomino Yeah, I think that’s a fair approximation of what we would consider to be the size of the system.
Tom Temin And of course, you’ll be able to measure all of its activities and parameters by telemetrics. Will it come back or will it just sort of burn out?
Anthony Calomino No. So, you know, on the first we will we will have it fully instrumented and we will have a robust pallet of information will be generated from the just it’ll be recorded, obviously digitally recorded will be transmitted back to Earth. We will be watching the operation of it real time. When the demonstration mission is over, the system will be left in a near circular orbit, thousands of kilometers away from Earth, and it will be safe there orbiting the Earth for as long as it has or represents any radiation concern to Earth itself. It would it would stay out there.
Tom Temin And when is the planned launch of this thing?
Anthony Calomino Right now, we believe that the launch will happen as early as calendar year 27. It’s a very aggressive schedule that we’re looking to conduct this mission on end. So we’re really quite anxious to get started.
Tom Temin And will NASA be fabricating and crafting this engine itself, or do you use contractors that have knowledge of nuclear systems?
Anthony Calomino So NASA will rely on an industry prime and actually NASA will actually be using some of the investments that DARPA has made up to this point to get some of the industry engaged on this. But NASA and DARPA have both had engagements with the industry over the past few years on this. So there’s a good alignment between both communities. We’re pretty well linked in terms of how we would look at that design to go in and how we would build it.
Tom Temin Right. So we won’t see it overhead mixing in with all the mysterious balloons or anything in the next few months. This is years out yet.
Anthony Calomino We’ll be very clear about what it is that we’re launching and what we’re testing.