Lockheed Martin Jets into Nuclear Electrical Spacecraft Power | Hacker News Reader

Lockheed Martin Jets into Nuclear Electrical Spacecraft Power

lockheedmartin.com

27 pointsulrischa16 comments

The nuclear-powered jet engine:

In 1954, GE even put a nuclear-powered jet engine on a test stand in Arco, Idaho. It ran for more than 100 trouble-free hours before the project was shelved. The idea was that the the engine would use heat produced by a nuclear reactor aboard the plane to generate thrust. A plane with these engines could theoretically stay in the air for days and weeks. Although the U.S. Air Force did modify a B-36 Peacemaker bomber to carry a nuclear reactor, it never used the engines.

From https://www.ge.com/news/reports/the-nuclear-powered-jet-engi...

The soviets flew nuclear powered planes for a while. http://www.aviation-history.com/articles/nuke-bombers.htm

I don't believe so? Your link doesn't say that those nuclear aircraft actually flew. (?)

I understand that the (claimed, alleged) 2023 nuclear cruise missile test [0] was the first, and only, nuclear-powered aircraft that has flown. All of the Cold War stuff was static-fire tested, at most.

[0] https://www.reuters.com/world/what-is-burevestnik-missile-th... ("What is the Burevestnik missile that Putin says Russia has tested?")

Huh. I thought I remembered that they had, and I thought the link agreed with me, but rereading it sounds like they just put a nuclear reactor on a plane and flew it to see if it would kill the crew.

"Between May and August 1961, the Tu-95LAL completed 34 research flights. Much of them made with the reactor shut down. The main purpose of the flight phase was examining the effectiveness of the radiation shielding which was one of the main concerns for the engineers. The massive amount of liquid sodium, beryllium oxide, cadmium, paraffin wax and steel plates; were the sole source of protection for the crew against the deadly radiation emerging from the core."

This died out because ICBMs mostly made cruising bombers obsolete as a first strike weapon, and also because people don’t like flying reactors.

It’d be so cool if we can make safe and light nuclear propulsion for commercial ships & planes.

The more we can boost human wealth, the better.

Whatever happened to the LockMart fusion reactor, announced with so much fanfare?

Let's just stipulate that LockMart has a long history of tragically over budget, and sometimes under-delivered hardware. Seems like a bad choice of vendor.

This was one of the coolest space projects NASA ever cancelled:

https://en.wikipedia.org/wiki/Jupiter_Icy_Moons_Orbiter ("Jupiter Icy Moons Orbiter")

(for background context on "what's nuclear-electric propulsion for?)

How would rocket propulsion work with nuclear fission or fusion? It would need to expel mass right?

I think they intend to use Hall Effect thrusters

Does that not produce a tiny thrust that’s only practical for small unmanned space probes?

If you want high thrust you just superheat reaction mass and expel it. Hydrogen gives you the best efficiency I think but is hard to handle. Water, carbon dioxide, and hydrocarbons are easy to handle. The nuclear engine can sustain much higher temperatures longer than a chemical engine to achieve both high thrust and higher specific impulse. You get a lot more delta V per unit rocket mass than just chemicals.

If you want maximum specific impulse (propellant efficiency) then you want what you are thinking of: a reactor powering ion engines. Ion engines can use very little propellant but generate low sustained thrust for a long time. Solar can power ion engines too, but I think a reactor can do so with less mass and solar becomes increasingly useless much beyond the orbit of Mars. If you want to visit Europa or Titan you need nuclear energy… or it’s a very very long trip.

Hybrids are possible too like a reactor that can run in either or both modes.

Nukes have the potential to be any-fuel reactors. Superheat your working fluid and throw it out the back. Fluids can be anything, within reason. Perfectly reasonable engine design for in-situ exploratory contexts.

Furthermore, I grow very convinced America fucked itself and the whole planet when it abandoned nuclear power several decades back. Unnameable ills and more on everyone involved in bailing on nuclear.

They feed the fuel into the reactor to superheat it and then it comes out the back like a normal rocket, but then doesn't need oxygen for the reaction to take place.

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