NASA, DARPA enlist Lockheed to build nuclear-powered spacecraft

NASA's ambitions to speed up space travel are about to go nuclear, as its joint project with military boffinry unit DARPA has found a builder for an experimental nuclear thermal rocket vehicle, or X-NTRV: Lockheed Martin. If all goes according to plan, NASA's Demonstration Rocket for Agile Cislunar Operations program (DRACO) …

[Tom Chiverton 1]

Also importantly, they can be refueled and reused until the reactor is cold..

[Anonymous Coward]

Perhaps even more important

Hygrogen won't become radioactive upon exposure to neutrons. Even if a tiny percentage becomes tritium, it's half life is only about 3 years. Deuterium is stable.

[harmjschoonhoven]

Nuclear propulsion

That has been tried before https://www.youtube.com/watch?v=fLK9hYXWZw4.

[Pascal Monett]

Re: Nuclear propulsion

I prefer this link.

It's much shorter, to the point and without any awful CGI.

[Yorick Hunt]

Look, up in the sky!

It's a bird! It's a 'plane! No, it's nuclear fallout :-\

Lockheed Martin, known for not being able to build a reliable 'plane even after receiving $trillions to get it going, is now being given the opportunity to screw something of much more consequence up.

[Anonymous Coward]

Re: Look, up in the sky!

As we know, the Russians have launched boatloads of reactors into orbit. The issue has been they didn't care where they crashed at end of life. Moon rockets can be sent into the sun.

[John Robson]

Re: Look, up in the sky!

"Moon rockets can be sent into the sun."

Yeah - if you happen to have about 30 km/s of delta V lying around.

The sun is very hard to get to.

[very angry man]

Oh goody

Merkins, nuclear powered (no way to scan for nuclear bombs) rocket s built by Merlin's, controlled by Merkin, govt dept yet to prove it self.

Be afraid, be very afraid, run VERY far, run VERY fast .

SPF 2850 sunscreen even at night and even on different planets and moon's, Merkin's don't care,

[fpx]

Having dangerously limited knowledge of the subject, I wonder why you would use hydrogen instead of, say, liquid nitrogen. Wouldn't that be easier to handle and more efficient, given its higher mass?

[Anonymous Coward]

Apparently (based on a very quick read of Wikipedia!) it is actually the opposite. You want high ISP from a rocket and the ISP is linked to the kinetic energy of each unit of propellent mass. But the KE per molecule of propellent is related only to the temperature. As the KE comes from the thermal energy you are better off with lighter molecules as you get more of them per unit of propellent mass (given that the temperature is usually limited by the materials you can use).

The same is technically true of chemical rockets as well but your "propellent" in this case is the exhaust gas and that is determined by what you burn. So there you have the combined effect of the combinations of chemicals that can generate the necessary thermal energy at the appropriate temperature but ideally burn to produce something with as light molecules as possible.

(shamelessly ripped off from here: https://en.wikipedia.org/wiki/Nuclear_thermal_rocket#Principle_of_operation )

[Alan Brown]

You can extract the hydrogen from water at the energies involved. Most of the proposals use water as reaction mass for this reason

[Alan Brown]

As Everyday Astronaut put it, nuclear thermal rocket propulsion is more or less operating a reactor at prompt criticality (as happened at Chernobyl) - on a continuous basis

That's a VERY fine knife edge to be riding, to say the least and it makes Project Orion look reasonable

[JohnTill123]

Whee!

Project Orion for the win!

If we can make a manhole cover go 150,000 mph with a small nuclear blast (Plumbob/Pascal-B only produced a blast equivalent of 300 tons TNT. ref: https://en.wikipedia.org/wiki/Operation_Plumbbob#Missing_steel_bore_cap ) then Project Orion should be considered.

Besides, the launches will be spectacular!

[annodomini2]

Always preferred NSWR

Ultra simple, no liquid hydrogen to handle.

Much better volumetric efficiency.

Probably take an ISP hit in trade for increased safety.

[spold]

...time to dig out the "Flesh Gordon" video...

[Bitsminer]

Ask Russia...

...how much they will charge for HALEU fuel pellets.

They're just about the only country making them. While the US is playing catchup:

https://www.energy.gov/ne/articles/us-department-energy-establishes-high-assay-low-enriched-uranium-consortium

HALEU is not available at commercial scale from domestic suppliers...

Not to mention any number of international players building or planning small modular nuclear reactors (SMRs) which also use HALEU.

https://world-nuclear-news.org/Articles/HALEU-fuel-availability-delays-Natrium-reactor-pro

TerraPower is anticipating a minimum of a two-year delay to being able to bring the Natrium reactor into operation.

It's an example of "supply chain vulnerability" at national scale. I would call it a cluster-fuck but that's rude.