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The US government is taking a step toward space-based nuclear propulsion

arstechnica.com

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Re: The US government is taking a step toward space-based nuclear propulsion

#31

Post by pdntspa »

somenameforme wrote: post #7
mdorazio wrote: post #2

Finally! This is one of the few fission uses I'm genuinely excited about. Nuclear-thermal just makes so much sense for in-space propulsion of large vessels compared to chemical rockets.

I think the obvious concern would be failure scenarios. There will always be failures in space technology. As space expands exponentially (as it is likely to do so in the future), failures will become relatively regular. So the obvious question would be what would happen if a nuclear rocket, with reaction in process, crashed to Earth. Or even if it broke up in the atmosphere.

Isn't there a way you can shoot the whole apparatus into the sky while it is inert and then activate in space?

Re: The US government is taking a step toward space-based nuclear propulsion

#32

Post by moffkalast »

65a wrote: post #11
flangola7 wrote: post #9

Earlier quoted context omitted.

RTGs do not use fission and do not create fission products. Nuclear fuels are harmless in comparison to Strontium-90 and Cesium-137.

Then you are going to love SNAP-10A https://en.wikipedia.org/wiki/SNAP-10A

And the 31 RORSAT reactors https://en.wikipedia.org/wiki/BES-5

Re: The US government is taking a step toward space-based nuclear propulsion

#33

Post by dotnet00 »

dtagames wrote: post #13

This might be a good time to review the number of failed rocket launches we've seen in the last few years. Now, imagine them with nuclear materials aboard.

Well that's the most obvious way to put FUD out there.

It might be a good time to review the number of failed launches on crew rated rockets (the safety requirements on which are roughly equivalent to the requirements for carrying nuclear material). Particularly ones which led to a loss of crew, as those would correspond most closely to a possible nuclear material release.

It's far less scary, but alas not as convenient for FUD.

Re: The US government is taking a step toward space-based nuclear propulsion

#34

Post by aziaziazi »

somenameforme wrote: post #7
mdorazio wrote: post #2

Finally! This is one of the few fission uses I'm genuinely excited about. Nuclear-thermal just makes so much sense for in-space propulsion of large vessels compared to chemical rockets.

I think the obvious concern would be failure scenarios. There will always be failures in space technology. As space expands exponentially (as it is likely to do so in the future), failures will become relatively regular. So the obvious question would be what would happen if a nuclear rocket, with reaction in process, crashed to Earth. Or even if it broke up in the atmosphere.

It already happened with Kosmos 954 and will probably happen again soon: ~20 other satellites had been sent in space with the same tech. Kosmos crashed away from (human) life centers but that was a huge stroke of luck. Research area was 100k+ km2.

Launches are less to be feared because they are oriented toward sea and the most critical moment are the first minutes. The device discussed is intended to travel away from earth so as you noted it won’t be dangerous after it quit orbit.

Disclaimer: not skilled in any related field, just a consumer of space science popularization videos for newbies.

Re: The US government is taking a step toward space-based nuclear propulsion

#36

Post by 0xDEF »

jamesaurichs wrote: post #21
mdorazio wrote: post #2

Finally! This is one of the few fission uses I'm genuinely excited about. Nuclear-thermal just makes so much sense for in-space propulsion of large vessels compared to chemical rockets.

US seems to be in a hardware/science renaissance, now that there is a new Cold War enemy, and manufacturing and research are being brought back to US.

From across the pond it feels like American millennials and Gen-Z have already declared their country to be a failed state.

How much can a nation progress if its youth is pessimistic about everything? It doesn't matter whether the pessimism is based on actual problems (healthcare, housing prices etc.) or learned through terminally online reddit/twitter consumption.

Re: The US government is taking a step toward space-based nuclear propulsion

#37

Post by asu_thomas »

ben_w wrote: post #16
dtagames wrote: post #13

This might be a good time to review the number of failed rocket launches we've seen in the last few years. Now, imagine them with nuclear materials aboard.

Depending on the design, failure during launch can be anywhere from "meh" to "basically high-altitude Chernobyl" — random actinide decay products (and plutonium fuel) are bad, unreacted uranium fuel is mostly a heavy metal hazard rather than a radiation hazard. (Could be worse, but the Orion drive is currently illegal by treaty and hopefully nobody is dumb enough to use that in Earth's ionosphere anyway).

What does "meh" mean? Is that english?

Re: The US government is taking a step toward space-based nuclear propulsion

#38

Post by zaptrem »

asu_thomas wrote: post #35
mdorazio wrote: post #2

Finally! This is one of the few fission uses I'm genuinely excited about. Nuclear-thermal just makes so much sense for in-space propulsion of large vessels compared to chemical rockets.

[flagged]

Investment in space has historically led to a disproportionate return in economic growth.

Re: The US government is taking a step toward space-based nuclear propulsion

#39

Post by db48x »

aio2 wrote: post #18
ben_w wrote: post #16

Earlier quoted context omitted.

Depending on the design, failure during launch can be anywhere from "meh" to "basically high-altitude Chernobyl" — random actinide decay products (and plutonium fuel) are bad, unreacted uranium fuel is mostly a heavy metal hazard rather than a radiation hazard. (Could be worse, but the Orion drive is currently illegal by treaty and hopefully nobody is dumb enough to use that in Earth's ionosphere anyway).

I remember learning that when they started testing atomic bombs (I think?) the nuclear debris in the air spread basically throughout the whole united states and the government tried to keep quiet about it. Something similar will probably happen here if they mess up with the launch. Btw, the video I saw was on Veritasium.

The thing to remember about that is that we can measure tiny amounts of radiation very cheaply, and tiny amounts are harmless. In fact we are bathed in a constant, but tiny, background level of radiation all the time. Thousands of nuclear weapons were tested all across the world, in the United States, in the Soviet Union, on Pacific Islands, etc, etc. The radiation from that certainly caused a small uptick in the background level of radiation, but it hasn’t actually harmed people.

The main reason that the US was secretive about it was that nuclear weapons were a secret, not because there was a shameful health problem to hide.

Incidentally, the best way to reduce your exposure to radiation is to move away from the mountains and go live at the beach. Mountains are mostly made of granite, and granite always contains small amounts of uranium and thorium which decay to radon gas. Also, live as far away from coal power plants as possible, those things are horrifying.

Re: The US government is taking a step toward space-based nuclear propulsion

#40

Post by bogota »

0xDEF wrote: post #36
jamesaurichs wrote: post #21

Earlier quoted context omitted.

US seems to be in a hardware/science renaissance, now that there is a new Cold War enemy, and manufacturing and research are being brought back to US.

From across the pond it feels like American millennials and Gen-Z have already declared their country to be a failed state. How much can a nation progress if its youth is pessimistic about everything? It doesn't matter whether the pessimism is based on actual problems (healthcare, housing prices etc.) or learned through terminally online reddit/twitter consumption.

Don’t confuse what you read online or in the news with what is actually happening.
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