9 ms·
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 comp
by mdorazio 3y ago
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.
- somenameforme 3y agoI 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.
- ethbr1 3y agoThe idea is also to use this for solar system propulsion, rather than Earth to orbit. Consequently, reactor payloads would be carried on a very small fraction of launches, then used in space for an extended amount of time.
- semi-extrinsic 3y agoI assume here you mean to denote by "space" the number of human spacecraft, and not the negative pressure contribution in the cosmological stress-energy tensor. In that case, why should it be likely to expand exponentially in the future?
- sebzim4500 3y ago>As space expands exponentially (as it is likely to do so in the future), failures will become relatively regular. It's possible that reliability/safety will improve as fast as the launch cadence does, in which case we could see the accident rate staying flat or decreasing.
- pdntspa 3y agoIsn't there a way you can shoot the whole apparatus into the sky while it is inert and then activate in space?
- nukeman 3y agoYes, you can have the reactor offline, with control rods inserted for launch. Then when you reach the requisite altitude, withdraw the control rods and start up the reactor. In the event of a launch accident and potential destruction of the reactor, the enriched uranium fuel would be a chemical hazard (uranium is a heavy metal like lead), but only a mild radiation hazard (since there are no high-gamma fission products, and the uranium has undergone heavy purification prior to fuel fabrication).
- m4rtink 3y agoI think this is the default for any launch of reactors from Earth - launch inert, possibly in pieces and ideally in re-entry proof capsules so you prevent contamination and can re-launch after a failure.
- aziaziazi 3y agoIt 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.
- flagrant_taco 3y agoIt's crazy to me that people largely consider it safe as long as the unspent fuel or nuclear debris is dumped into the ocean. (Not a direct comment on your opinion specifically, just building of the general idea)
- adastra22 3y agoBecause it largely is? It ends up on the sea bed, covered in sediment, then eventually recycled into the Earth’s mantle some millions of years from now. It doesn’t enter the biosphere.
- aziaziazi 3y agoOceans, marine fauna and marine flora are part of the biosphere.
- adastra22 3y agoNone of those exist in the regions where these satellites and rocket stages crash. These are natural dead patches.
- aziaziazi 3y agoAny evidence/reference to back this up? Oceans are the cradle of life and are still populated by fishes, mammals, zoo and phytoplancton even away from coastlines. http://comlmaps.org/gallery/footprints/ http://comlmaps.org/gallery/footprints/
- avar 3y ago> Or even if it broke up > in the atmosphere. The atmosphere we've already detonated over 500 nuclear weapons in?
- pixl97 3y agoMostly about the ocean it would typically fall into in the most common failure shortly after launch scenario.
- Retric 3y agoNuclear testing got to carefully select locations to minimize harm, uncontrolled reentry of nuclear rockets has significantly less control. It’s not the 99 rockets falling into the ocean shortly after launch that are problematic, it’s the 1 that almost works but then lands in the city we should be concerned with.
- TheSpiceIsLife 3y agoHow often do failed rockets, or any space debris, fall on cities?
- askvictor 3y agoNot falling on a city, but debris from Russia's launch last week was seen and heard in Melbourne, Australia: https://www.abc.net.au/news/2023-08-08/space-junk-leaves-trail-across-melbourne-sky/102700674 https://www.abc.net.au/news/2023-08-08/space-junk-leaves-tra... That's pretty close for what would be high level nuclear material.
- flagrant_taco 3y agoWe might see more obvious direct human impact from debris landed in cities, but nuclear debris falling into the ocean or land that isn't densely populated by humans still has plenty of bad side effects.
- m4rtink 3y ago
- SkyMarshal 3y ago>As space expands exponentially (as it is likely to do so in the future), failures will become relatively regular. Or it could go the way of the airline industry where failures become less regular as the industry develops ways of systematically reducing them. Also, nuclear rockets should probably be launched to earth orbit in pieces, separately, so that if any one launch fails it won’t create a nuclear accident in the biosphere. Then assemble and power up the nuclear rocket as far away from earth as possible.
- numpad0 3y agoThe solution to this is to build it in the moon from moon rocks and send it by maglev trains. Full scale spaceships can be 3D printed in parts, assembled on-orbit, and Dragon/Starliner class rowboats can be used to board it.
- m4rtink 3y agoLonger term - definitely thats the way to go. But first we need to build all this infrastructure & nuclear termal propulsion might be already necessary to get there.
- jamesaurichs 3y agoUS 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.
- echelon 3y agoPeace time = smart phone incrementalism, social media, ad tech, Bitcoin, NFTs, WeWork, low interest rate malinvestment, Twitter/Tumblr pessimism Cold war = rocket science, new fuels, materials science, major computing advancements, supply chain changes, innovation, science hype, broad optimism I know most of this is happenstance and that peace time doesn't itself cause lackluster development, but it is interesting and palpable. I was so down on 2000 - 2020, but the decade ahead is exciting, and I'm filled with motivation.
- vkou 3y agoBroad optimism? Science hype? Are we living in the same country?
- rbanffy 3y agoOne thing I learned from the outside, the US - like any large country, BTW - is wildly diverse in pretty much every aspect.
- cheese_van 3y agoIt's almost intuitive if you consider the distance from Bangor to LA is pretty much the same distance as Madrid to Moscow. Think of the diversity between Madrid and Moscow. Bangor to LA won't take you through an equal amount of diverse cultures, the US is a single country after all, but the diversity is certainly there.
- rbanffy 3y agoNot that intuitive, as the country has a language in common and one can simply drive from Bangor to LA without any local government asking questions. I have the impression cultural differences spring more from the economic and educational ones, unlike Madrid and Moscow, which have very long histories that are almost completely disconnected for most of that time.
- asu_thomas 3y ago[flagged]
- zaptrem 3y agoInvestment in space has historically led to a disproportionate return in economic growth.
- FirmwareBurner 3y agoProbably because there is no oil in space and nobody to sell ads to.
- version_five 3y agoIt's funny because it's this, turning inward and waging war on ourselves after there wasn't an obvious enemy anymore that's responsible for the decline the upstream comment was talking about. Post WWII through the 90s saw massive increases in global standard of living, 2020's the west has gone back to religious squabbles over absurd ideological things. Watchmen had a similar idea.
- pixl97 3y agoPost WWII understood how terrible war was. Post 90s those that experienced it in mass were going extinct. We forgot what fascism did to the past and too many are embracing it again.
- WalterBright 3y agoOr the definition of fascism has expanded to cover all one's political enemies.
- pixl97 3y agohttps://youtu.be/9XTJNy_OrjE https://youtu.be/9XTJNy_OrjE Why does the definition need expanded?