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NASA Wants to Send Nuclear Rockets to the Moon and Mars

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Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#61

Post by mlindner »

SketchySeaBeast wrote: post #7
api wrote: post #3

Earlier quoted context omitted.

I don't know for certain but I'm fairly sure that the idea is that you don't activate the reactor until it's in space. Before a reactor is turned on the fuels are less radioactive. It's once you turn it on that radioactivity increases dramatically and you get all the nasty decay products and such. So not zero but not as much as you might think. Personally I don't like the idea. Environmental concerns are real, but th…

> "The massive amount of energy produced by these reactors could be used to sustain human outposts on other worlds and cut the travel time to Mars in half. >“Many space exploration problems require that high-density power be available at all times, and there is a class of such problems for which nuclear power is the preferred—if not the only— option,” It seems that nuclear reactors has more utility than simple power…

Nuclear reactors will be needed if you're going much further out than Earth/Mars. Solar power falls off rapidly as you go further out.

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#62

Post by mitchty »

ianai wrote: post #19
Bud wrote: post #17

Earlier quoted context omitted.

Um, uh, um, uh...where to start? "Mined" from where? How?

The moon? Asteroids? Or even just ship up unrefined ore such that a catastrophic failure can’t threaten the population.

Neither of the first two are options... at all realistically, nither uranium nor thorium exist in anything below a large planetary size body in any quantity: https://www.quora.com/Do-uranium-and-thorium-exist-in-signif...

And shipping up unrefined ore is also a bit of a ludicrous idea for mass reasons and the rocket equation alone. You do realize you can isolate a nuclear reactor core from explosions on rockets right? What catastrophic failures are you attempting to design your solution of avoiding a nuclear reactor around?

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#63

Post by exhilaration »

om3n wrote: post #43
simonh wrote: post #37

Earlier quoted context omitted.

You do what you would on a terrestrial reactor, and shut down the reactor e.g. by using control rods, or pulling out fuel rods to shut down the chain reaction. These wouldn't be simple radiothermal devices, but proper actively managed reactor cores. Having said that you absolutely would need active cooling even in a 'shut down' state, probably by circulating a cooling fluid to radiator fins. You might use the same fl…

but what cools the radiator fins, in the absence of air?

If you look at diagrams of the International Space Station you'll see they have rather large radiators, so it does work in space. They're always positioned in shade to radiate heat most efficiently. It's the two long pieces labeled 11 in this diagram: https://www.nasa.gov/sites/default/files/thumbnails/image/it...

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#64

Post by NohatCoder »

simonh wrote: post #37
DoctorOetker wrote: post #26

what happens at the end of such a trip, when the propellant is exhausted, and can no longer evaporatively cool the core? it has to contain enough propellant to come back to Earth orbit to refuel the propellant coolant? even if the core is throttled to its lowest levels, it will still produce heat in the vacuum of space? or will radiative cooling balance the remaining production of heat?

You do what you would on a terrestrial reactor, and shut down the reactor e.g. by using control rods, or pulling out fuel rods to shut down the chain reaction. These wouldn't be simple radiothermal devices, but proper actively managed reactor cores. Having said that you absolutely would need active cooling even in a 'shut down' state, probably by circulating a cooling fluid to radiator fins. You might use the same fl…

Absolutely not, in space you have the option of jettisoning the core, carrying coolant for a controlled shut down is a waste of weight. You might even go as far as having 4 disposable cores, one for each acceleration stage.

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#65

Post by marcosdumay »

cr0sh wrote: post #52
BAReF00t wrote: post #22

I’m disappointed. I expected a project-Orion-type interstellar solution. Not a measly ”twice as fast as conventional“ water kettle. Also, no word about what they will acually use. Because classic uranium is a quite limited resource actually. It has been said to run out even before fossil fuels. Also, why not a fusion rocket? Given that we know how to make fusion bombs. Because until we find a massive amount of anti-m…

> Because until we find a massive amount of anti-matter I honestly hope this never occurs, or we never are able to contain/store such a mass for any real length of time. Because if we can do it, it will be used for a weapon. Seriously - I can't even imagine what - for instance - one kilogram of anti-matter coming in contact with regular matter - the amount of energy that would be released...it staggers the imaginatio…

Well, the Tsar Bomba was made as a single of a kind, ust for testing, and at half of its designed size because a bomb of that size is basically useless.

So I don't think we would get larger warheads. It's more likely we would get smaller ones, at power levels that can be used, and use their small weight as a feature. (Not something great, but I don't think we will ever use an Earth Crust removing bomb.)

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#66

Post by ceejayoz »

sq_ wrote: post #60

> which will almost certainly be used on any crewed mission to Mars. This is interesting. I hadn't seen anything about NASA plans to get humans to Mars requiring nuclear-thermal propulsion. Does NASA even currently have a serious plan for Mars missions with the whole Artemis thing going on?

They branded Artemis as part of a larger "Moon to Mars" plan, with logo and all. https://www.nasa.gov/moontomars/

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#67

Post by sq_ »

ceejayoz wrote: post #66
sq_ wrote: post #60

> which will almost certainly be used on any crewed mission to Mars. This is interesting. I hadn't seen anything about NASA plans to get humans to Mars requiring nuclear-thermal propulsion. Does NASA even currently have a serious plan for Mars missions with the whole Artemis thing going on?

They branded Artemis as part of a larger "Moon to Mars" plan, with logo and all. https://www.nasa.gov/moontomars/

Interesting. I'm kinda down on Artemis overall, as it seems like the whole thing is getting bogged down in political maneuvering, as usual.

NASA keeps saying it's more than boots on the ground, but all the plans they announce seem to be boots on the ground or overly complicated paths to the surface meant to please contractors.

This gem of a line from this week's Orbital Index kinda sums up why I'm preparing for disappointment:

>"Meanwhile, contractors (cough Boeing? cough) are pushing for the Gateway plan to be nixed in favor of… The Exploration Upper Stage, a large interplanetary upper stage (launched on SLS Block 1B) in development by (wait for it) Boeing."

Boeing and the SLS have taken forever already, and the version that may launch soonish isn't even the "real" SLS.

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#68

Post by dvdhnt »

NohatCoder wrote: post #64
simonh wrote: post #37

Earlier quoted context omitted.

You do what you would on a terrestrial reactor, and shut down the reactor e.g. by using control rods, or pulling out fuel rods to shut down the chain reaction. These wouldn't be simple radiothermal devices, but proper actively managed reactor cores. Having said that you absolutely would need active cooling even in a 'shut down' state, probably by circulating a cooling fluid to radiator fins. You might use the same fl…

Absolutely not, in space you have the option of jettisoning the core, carrying coolant for a controlled shut down is a waste of weight. You might even go as far as having 4 disposable cores, one for each acceleration stage.

Serious questions...

Would the core just float off into space? Couldn't it make its way back to Earth? Or compromise potential life on Mars?

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#69

Post by ceejayoz »

sq_ wrote: post #67
ceejayoz wrote: post #66

Earlier quoted context omitted.

They branded Artemis as part of a larger "Moon to Mars" plan, with logo and all. https://www.nasa.gov/moontomars/

Interesting. I'm kinda down on Artemis overall, as it seems like the whole thing is getting bogged down in political maneuvering, as usual. NASA keeps saying it's more than boots on the ground, but all the plans they announce seem to be boots on the ground or overly complicated paths to the surface meant to please contractors. This gem of a line from this week's Orbital Index kinda sums up why I'm preparing for disap…

I'm skeptical of any human exploration plans NASA has beyond 2-4 years or so. Anything more and the next President winds up nixing it to put their own stamp on things.

My money's on a commercial program like they one they've been doing for ISS resupply.

Re: NASA Wants to Send Nuclear Rockets to the Moon and Mars

#70

Post by ceejayoz »

dvdhnt wrote: post #68
NohatCoder wrote: post #64

Earlier quoted context omitted.

Absolutely not, in space you have the option of jettisoning the core, carrying coolant for a controlled shut down is a waste of weight. You might even go as far as having 4 disposable cores, one for each acceleration stage.

Serious questions... Would the core just float off into space? Couldn't it make its way back to Earth? Or compromise potential life on Mars?

It's pretty straightforward to put it in a safe, permanent orbit.

https://en.wikipedia.org/wiki/Graveyard_orbit

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