NASA Wants To Send Nuclear Rockets To the Moon and Mars (wired.com) 111
NASA engineers want to create a rocket engine powered by nuclear fusion. "A nuclear rocket engine would be twice as efficient as the chemical engines powering rockets today," reports Wired. "But despite their conceptual simplicity, small-scale fission reactors are challenging to build and risky to operate because they produce toxic waste. Space travel is dangerous enough without having to worry about a nuclear meltdown. But for future human missions to the moon and Mars, NASA believes such risks may be necessary." From the report: At the center of NASA's nuclear rocket program is Bill Emrich, the man who literally wrote the book on nuclear propulsion. "You can do chemical propulsion to Mars, but it's really hard," says Emrich. "Going further than the moon is much better with nuclear propulsion." Emrich has been researching nuclear propulsion since the early '90s, but his work has taken on a sense of urgency as the Trump administration pushes NASA to put boots on the moon ASAP in preparation for a journey to Mars. Although you don't need a nuclear engine to get to the moon, it would be an invaluable testing ground for the technology, which will almost certainly be used on any crewed mission to Mars.
Let's get one thing clear: A nuclear engine won't hoist a rocket into orbit. That's too risky; if a rocket with a hot nuclear reactor blew up on the launch pad, you could end up with a Chernobyl-scale disaster. Instead, a regular chemically propelled rocket would hoist a nuclear-powered spacecraft into orbit, which would only then fire up its nuclear reactor. 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. [...] But before a nuclear rocket engine gets its first flight, NASA needs to overhaul its regulations for launching nuclear materials. In August, the White House issued a memo that tasked NASA with developing safety protocols for operating nuclear reactors in space. Once they're adopted by NASA, the stage will be set for the first flight of a nuclear engine as soon as 2024. This coincides with Trump's deadline to return American astronauts to the moon; maybe this time they'll be hitching a ride on a nuclear rocket.
Let's get one thing clear: A nuclear engine won't hoist a rocket into orbit. That's too risky; if a rocket with a hot nuclear reactor blew up on the launch pad, you could end up with a Chernobyl-scale disaster. Instead, a regular chemically propelled rocket would hoist a nuclear-powered spacecraft into orbit, which would only then fire up its nuclear reactor. 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. [...] But before a nuclear rocket engine gets its first flight, NASA needs to overhaul its regulations for launching nuclear materials. In August, the White House issued a memo that tasked NASA with developing safety protocols for operating nuclear reactors in space. Once they're adopted by NASA, the stage will be set for the first flight of a nuclear engine as soon as 2024. This coincides with Trump's deadline to return American astronauts to the moon; maybe this time they'll be hitching a ride on a nuclear rocket.
After a few of the fusion rockets are built (Score:3)
Can we make a few extra and keep them here on earth so humanity can have limitless clean practically free energy?
Askin for a friend
Re:After a few of the fusion rockets are built (Score:5, Informative)
The word "fusion" does not appear in the article. The word "fission" appears several times.
And, yes, we will have many similar fission reactors on Earth to provide us limitless, clean, and practically free energy.
Re:After a few of the fusion rockets are built (Score:5, Insightful)
The word "fusion" does not appear in the article. The word "fission" appears several times.
And, yes, we will have many similar fission reactors on Earth to provide us limitless, clean, and practically free energy.
Shame on whoever modded this down; the article is about nuclear thermal rockets, which use fission. (Fusion rockets would have orders of magnitude greater performance, but they're also orders of magnitude further into the future, while nuclear thermal rockets were built and successfully test-fired from the 50s to the 70s.)
First line is wrong: fission, not fusion (Score:3)
Right: the first line of the summary of the article is wrong.
We'd love to have a fusion rocket, but nobody has solved that problem yet. This article is about fission.
About NTREES (Score:3)
Same. Saw fusion in summary... thought how could that be, we don't have fusion in a practical sense on land. Bit of RTFA'ing and Google got me this:
http://large.stanford.edu/cour... [stanford.edu]
Fission.
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We could build a fusion rocket easily enough. We could build a fusion power plant pretty easily too. The issue is the scale required.
https://en.wikipedia.org/wiki/... [wikipedia.org]
https://en.wikipedia.org/wiki/... [wikipedia.org]
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The word "fusion" does not appear in the article. The word "fission" appears several times.
And, yes, we will have many similar fission reactors on Earth to provide us limitless, clean, and practically free energy.
Shame on whoever modded this down;
Shame on you for propping up a troll and a known shill.
Whilst that may be true about fission rockets operated in space we have already proven that fission reactors on Earth to provide us limitless, clean, and practically free energy is an oft repeated lie for people who want a cognitive shortcut to appear smart by using social proof.
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"Limitless" in the sense that all the ready ore will be used up within a couple hundred years if we actually replace our fossil fuel use with nuclear
"Clean" in the sense that we have no waste reprocessing plan, and the decommissioning is a dirty process which always winds up costing the taxpayer a bunch of money.
"Practically Free" in the sense that it is literally the most expensive way to make base load power. "Too cheap to meter" was the original lie upon which Nuclear was sold to the public, and here you
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Why is this modded down when it points out facts.
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"Limitless" in the sense that all the ready ore will be used up within a couple hundred years if we actually replace our fossil fuel use with nuclear
So even if no new sources are found and no technological advances are made we have enough to last for centuries at today's prices?
"Clean" in the sense that we have no waste reprocessing plan, and the decommissioning is a dirty process which always winds up costing the taxpayer a bunch of money.
So it's clean if we legalize known methods and plan better?
"Practically Free" in the sense that it is literally the most expensive way to make base load power.
France has one of the lowest electricity prices in Europe, and it's easy to find well-sourced quotes like "nuclear power had the lowest electricity production costs at 2.10 cents per kilowatt hour", so...
"Too cheap to meter" was the original lie upon which Nuclear was sold to the public, and here you are, telling the same lie, as usual.
No, that was an optimistic hope for the future one person had when talking to science fiction writers.
So you're batting a zero, which is your usual average. Why do you even show up to play any more?
Every argument yo
Re: After a few of the fusion rockets are built (Score:2)
Read. The. First. Sentence.
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I did.
The first sentence of TFA doesn't use the word "fusion". Neither does the second.
Now, the first sentence of TFS does use the word "fusion". Which just shows that whoever wrote TFS doesn't know the difference between fission and fusion....
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The /. editors are morons. They almost never fix even the most rudimentary errors in their articles. I have no idea why.
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Elon Musk and SpaceX have built an efficient methane-oxygen engine, the Raptor. It is the first FFSC (full flow, staged combustion) engine to ever fly. The SpaceX Starship is under construction now and will eventually be able to make a round trip to Mars. Talk of fusion engines in space is just another excuse by people who don't care about going to Mars but care very much about building fusion reactors.
Re:After a few of the fusion rockets are built (Score:4, Informative)
Elon Musk and SpaceX have built an efficient methane-oxygen engine, the Raptor. It is the first FFSC (full flow, staged combustion) engine to ever fly.
There is an excellent article on the Everyday Astronaut website about the technical challenges and advantages of this design, as well as some history on rocket engine development.
https://everydayastronaut.com/... [everydayastronaut.com]
Talk of fusion engines in space is just another excuse by people who don't care about going to Mars but care very much about building fusion reactors.
The summary is in error, nuclear fusion rockets are not mentioned in the article. All proposed nuclear rockets use fission.
People who care about going to Mars, or even going to the moon again, will care very much about space based fission power. As it stands now NASA is in a bit of a panic over a shortage of Pu-238, a byproduct of nuclear fission and a vital isotope for energy dense sources of heating and electricity. Pu-238 heating units were used on Apollo missions up to Apollo 11, and Pu-238 heat and electrical units were used after that. Nuclear fission got us too the moon. We will need nuclear fission to go to Mars.
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Sure, if you want to spend 100x as much on your propulsion system, worsen your mass ratio for the overwhelming majority of missions, and be forced to mine more in-situ resources to refuel, then go ahead and use an NTR. Otherwise use methalox for going to Mars and hydrolox for going to most other places.
Did you tell the rocket scientists at NASA that they are doing it all wrong? Make sure you get in touch with them, I'm sure they'd appreciate your input. Maybe they'd even offer you a job.
I'm fairly certain NASA is on the right path here. They'll almost certainly need a nuclear thermal rocket for manned missions to Mars. When they get there they'll need something like Kilopower/KRUSTY to keep the lights on in their habitat once they land.
https://en.wikipedia.org/wiki/... [wikipedia.org]
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Did you tell the rocket scientists at NASA that they are doing it all wrong?
NASA has been doing so many things wrong in the past that it's easy to not notice new things being done wrong as well. It's business as usual. And why would I have to tell anything to people toying with things? As long as they're just toying with them, they're harmless anyway. Let them play. Whether they're doing the right things or the wrong things is almost immaterial with research at this stage. Plus, NASA is not the place where new space transportation systems get developed these days after all.
They'll almost certainly need a nuclear thermal rocket for manned missions to Mars.
Don't be
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When they get there they'll need something like Kilopower/KRUSTY to keep the lights on in their habitat once they land.
Yeah, and about that...a few watts per kg of downmass is not going to be competitive here, even considering just today's alternatives, not to mention the future ones. So, they would need something very different than that.
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NASA has had such a splendid saftety record recently, what could possibly go wrong?
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Nuclear fission to the moon does not make sense. ... a nuclear rocket won't cut that significantly (aka down to 3 hours or something).
The Apollo missions took a day or so
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Nuclear fission got us too the moon. We will need nuclear fission to go to Mars.
It wasn't fission, it was decay heat from pu-238 used in Radioisotope thermoelectric generator [wikipedia.org].
As usual you treat everyone here with contempt and never let the facts get in the way of the narrative you make up.
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It wasn't fission, it was decay heat from pu-238 used in Radioisotope thermoelectric generator .
As usual you treat everyone here with contempt and never let the facts get in the way of the narrative you make up.
I didn't claim that the heating units that went to the moon were fission resctors. I made the claim that the Pu-238 came from fission rectors. Something pointed out on Wikipedia.
https://en.wikipedia.org/wiki/... [wikipedia.org]
It's also made clear in my previous post.
As it stands now NASA is in a bit of a panic over a shortage of Pu-238, a byproduct of nuclear fission and a vital isotope for energy dense sources of heating and electricity.
Don't let my relaying facts get in the way of your propping up a straw man.
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Nuclear fission got us too the moon.
It wasn't fission, it was decay heat from pu-238 used in Radioisotope thermoelectric generator .
As usual you treat everyone here with contempt and never let the facts get in the way of the narrative you make up.
I didn't claim that the heating units that went to the moon were fission resctors.
You implied the process got us to the moon when it was the by-products of the process that got us to the moon. As usual you distorted the fact to promote your idealistic view of nuclear energy.
This is a classic example of how you post subtle little lies in an attempt to mess with people's perception of the nuclear industry.
Don't let my relaying facts get in the way of your propping up a straw man.
And don't let reality get in the way of you treating everyone here with contempt.
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You implied the process got us to the moon when it was the by-products of the process that got us to the moon.
It was the process of fission that got us to the moon. The Pu-238 produced from nuclear fission was a vital component for the success of the mission. Without nuclear fission there would have been no Pu-238. Without Pu-238 there would have been too much mass to launch.
If we don't have a source for more Pu-238 then there will be considerable limitations on future space exploration. So much of a limitation that any manned mission to the moon or Mars may not happen. We've lost space probes to a lack of pow
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It took an "Atomic Age" culture to go to space. Abandoning nuclear power is abandoning space exploration.
No it won't. There is and over-abundance of DU and the Neptunium used to make it can be recycled. It is the function of research reactors to create pu-238 and not power reactors. PU238 production restarted in 2015 at INL.
Simply put, your bullshit doesn't work on me.
Your failure to read what I wrote does not make my statement a lie.
The fact that it is demonstrably false makes it a lie.
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No it won't. There is and over-abundance of DU and the Neptunium used to make it can be recycled. It is the function of research reactors to create pu-238 and not power reactors. PU238 production restarted in 2015 at INL.
So, you are saying we don't need nuclear reactors because we have nuclear reactors? So, you concede that it takes Atomic Age technology to go to space. Thanks.
Tell me, how are we supposed to "recycle" neptunium that's been launch on a probe into deep space? You use that word but I don't think it means what you think it means.
Simply put, your bullshit doesn't work on me.
Whatever. Give it a few years and we will see what happens. My prediction is another 100 nuclear power reactors getting built in the USA to replace the 100 we have now reaching the
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No it won't. There is and over-abundance of DU and the Neptunium used to make it can be recycled. It is the function of research reactors to create pu-238 and not power reactors. PU238 production restarted in 2015 at INL.
So, you are saying...
That you lie.
Everything in your reply is an irrelevant distraction to attempt to hide that. Clearly you don't understand how pu-238 is produced and how abundant source material is. Research reactors are not power reactors and the likelihood of Canadian reactors being approved for construction in the US extremely remote.
There was no fission process functioning on the moon missions as you attempted lead people to believe when you said "Nuclear fission got us too the moon".
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Research reactors are not power reactors
I did not say that they were, only that fission reactors (both the kind used primarily for power and the kind primarily used for research) were used to produce Pu-238 for NASA.
and the likelihood of Canadian reactors being approved for construction in the US extremely remote.
I agree, because (as I recall) the PHWR reactors have a positive void coefficient which disqualifies them for a license under current NRC rules. I merely stated that I believed it would be wise for the USA to use this same design, knowing that it would be unlikely. Stating that we should have them is different than stating we would,
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Like I wrote earlier, your misinterpretation of what I wrote does not make me a liar.
The onus of clear communication is on the person delivering the message, yet here you are trying to shift the blame and employ pedantic over qualifications of your statements. You have a history of ambiguous communication designed to mislead people and treat them with contempt which excludes errors on your part. You have demonstrated you have a political agenda and have been exposed lying in the past.
That is what makes your statement a lie.
Nuclear *fission*, not fusion (Score:5, Informative)
Error in summary. From the article: "This time NASA engineers want to create something deceptively simple: a rocket engine powered by nuclear *fission*."
Re: Nuclear *fission*, not fusion (Score:5, Informative)
Unfortunately the article itself is full of errors too. ... That would be scary!
The writer clearly does not understand the advantage of nuclear - that it lets you use hydrogen propellant, which means a much higher specific impulse than from combustion products.
Also, a launchpad failure would not be remotely comparable to Chernobyl. Aside from the reactor being tiny in comparison, it would contain almost no fIssion products when first started.
But doing a propulsive landing after returning from Mars
Re: Nuclear *fission*, not fusion (Score:5, Funny)
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the advantage of nuclear - that it lets you use hydrogen propellant
That's hardly an "advantage", since it's ~5x more voluminous than the same mass of hydrolox propellant, or ~12-14x as voluminous as other common propellant mixtures. With the result that for the same performance, you actually need significantly bigger tanks - or, you get lower performance for a vehicle of the same size (that's even ignoring the significantly higher engine mass which decreases payload performance further for reason of increasing dry vehicle mass).
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I think you missed the part where this would be used in space and not in gravity Wells
Yes, you're right, but those are really only issues when talking about escaping Earth.
Going between planets, it's not a big deal. We would probably need chemical Landers until better engineering comes along.
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TFA is wrong on this, unfortunately. The advantage of nuclear thermal engines is that you can get your propellant righteously hot, far hotter than material science permits us to use safely. It gets you an ISP of around 1,000. This gives you the efficiency of an ion engine without the power requirements and slow-as-molasses acceleration. Also you can use (abundant) hydrogen instead of (rare) xenon.
You are correct regarding the tanks. You certainly wouldn't fly one of these in an atmosphere. If you coul
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The advantage of nuclear thermal engines is that you can get your propellant righteously hot, far hotter than material science permits us to use safely.
Not with the current ones, actually. If you had an open cycle NTR, you could get to Isp levels where the low density drawback is eliminated (that would be maybe around 3000 s of Isp). But we don't have those (yet - and considering how they work, it might be a problem to convince people to build them).
It gets you an ISP of around 1,000. This gives you the efficiency of an ion engine
That would be a very bad ion engine. It would also be slightly worse than a solar thermal engine. *That* (at least in a direct heating form) would allow you to make the propellant measurably hotter than any exi
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The advantage of nuclear thermal engines is that you can get your propellant righteously hot,
No, that's not it at all. You still have the same limits on temperature as conventional rockets. But hydrogen gas as propellant gives you a much higher specific impulse at the same temperature, compared to the H2O and CO2 combustion products. Average speed of a gas is inversely proportional to the square root of the molecular mass. So smaller molecule is better.
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Perhaps you did not read carefully.
Launchpad only refers to using nuclear fission engines for launch, and yes: if that would fail it would be a Chernobyl like disaster.
So the conclusion is to have small contained reactors for the final stage. Easy to grasp actually ...
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Vixen https://en.wikipedia.org/wiki/... [wikipedia.org]
ie "Vixen B scattered 22.2 kg of plutonium"
Nothing near a Chernobyl event. Depending on the amount used.
Re: Nuclear *fission*, not fusion (Score:2)
Fresh uranium reactor fuel is relatively harmless. The problem from Chernobyl was the months or years of accumulated fusion products, notably iodine, strontium and caesium . There would not be significant release of these in a launch failure of a nuclear thermal rocket, if it had fresh clean fuel rods.
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Consider this: we're already having a nigh-unto impossible time
getting NIMBYs and other scared little rabbit-types to
accept that we need nuclear power here on Earth
The only fear most people have regarding nukes is the fear of bankruptcy.
Virtually every nuke plant in the last 30 years has come in
far over budget. And that doesn't include the cost of cleanup, or the fact that the
taxpayers end up indemnifying the project since no private insurance firm would touch one.
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? Comparing to Chernobly is laziness because it is what people know. The risk is completely different from a earth based nuclear reactor. A hot reactor could spread something like plutonium far into the atmosphere
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Conventional nuclear reactors
You keep using that phrase. I am afraid I have some bad news for you. The name you were looking for is RTG or radioisotope thermoelectric generator. A nukular reactor is something else. Something not great, but not terrible.
Re: Nuclear *fission*, not fusion (Score:2)
Yes, and furthermore, "ability to launch a full earth type nuclear reactor into space, " has been there since the 1960s. The Russians launched dozens of TOPAZ reactors. Americans tested one in space, and tested a nuclear rocket on the ground, though it was never launched. As now, it was considered as upper stage, where the advantage is much greater.
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Actually, they only launched two TOPAZ reactors, not "dozens". You might be thinking of BES-5, perhaps?
Oops, thanks for correcting that :-) Both are small fission reactors, not RTG.
The real precedent is NERVA https://en.wikipedia.org/wiki/... [wikipedia.org]
With a weight of 18 tons and a thrust of only 24 tons, it was never going to be used in a first stage.
Fission. Not Fusion. (Score:2)
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Rechargable (Score:1)
FREE to Colonize Mars (Score:1)
Project Orion again? (Score:1)
https://en.wikipedia.org/wiki/... [wikipedia.org]
The reason they didn't build it was the Partial Test Ban Treaty of 1963. So the US would have to leave that, too.
Re: Project Orion again? (Score:3)
No, the article is about a nuclear thermal rocket, ie using a small reactor. Orion was way cooler: riding into space on the shockwaves of hundreds of atomic bombs.
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Even better, fusion bombs, to make the summary more accurate.
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No. NERVA again.
Orion never got beyond a conceptual stage, and would never be built in the manner conceived, test ban treaty or no.
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Depends. We might do it if a bunch of elephant-like aliens arrived in the solar system, dropped an asteroid on us, and announced they were our new overlords.
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No worries. They don't have thumbs.
The Fithp had bifurcated trunks.
IOW (Score:1)
"But for future human missions to the moon and Mars, NASA believes such risks may be necessary."
Florida, you're fucked!
Re:IOW (Score:5, Informative)
"But for future human missions to the moon and Mars, NASA believes such risks may be necessary."
Florida, you're fucked!
Did you even read the fine article? Oh, right, this is Slashdot. You apparently didn't even read the summary. The first stage engines, those in operation to lift off from Florida, will be traditional chemical rockets. The engine that sends the manned craft from Earth orbit to Mars orbit will be the nuclear engines. On take off from Earth the nuclear engine will be inert. If there is a loss of the rocket while in the atmosphere then the enriched uranium core will land in the ocean. Since uranium is a naturally occurring element in seawater the addition of whatever amount of uranium on the rocket will pose no danger. Well, no more danger than any other rocket that falls into the sea.
The uranium core will likely be made of uranium oxide, something already occurring naturally on Florida beaches.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Return Flight (Score:2)
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Since uranium is a naturally occurring element in seawater the addition of whatever amount of uranium on the rocket will pose no danger.
Unless it hits a place close to where you live.
Why posting bullshit all the time? You have nothing better to do?
The uranium concentration in the ocean is so low it is not even worth trying to harvest it.
If a few kg drop into your food supply: you die. It is more poisoness than mercury or cadmium.
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That was a lot of "uranium concentration" all over oceans and on land.... for many years.
We already did it - project NERVA (Score:3, Insightful)
As several commenters have pointed out, the article talks about using fission - not fusion.
Also, nuclear fusion (not fission) could indeed be used to launch rockets.
My final point is the horrendous waste the government produces. The US government had created a highly successful nuclear fission rocket engine during the 1960s. It was Project NERVA. After seven prototypes and a huge amount of money, it was canned because. Such waste.
Using nuclear fission in space is perfectly safe. Space is full of radiation anyway. And if one has a meltdown, just send the engine into the Sun. The Sun could goggle up the entire Earth and not even burp. There is no waste disposal problem in space.
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Just don't accidentally send the Stargate towards the sun...
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Umm, no. DeltaV required to reach the sun is on the order of 30km/s. With an Isp 1000 fission drive (pretty high-end solid core drive), we're talking 95% of the ship's mass is fuel required to abort into the Sun.
That said, if you start having issues, rotate 90 degrees, and push reaction mass through the core until you have none left. Which
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The plus side of a nuclear drive (orbit to orbit, not going to land it on Mars, nor back on Dirt) is that we get to reduce the reaction-mass load of the spacecraft from about 85% fuel to about 45% fuel. Which means a LOT more useful stuff (food, living space, men, rovers, landers, etc, etc, etc,...)....
But without something like LANTR, your spacecraft will significantly increase in size, *or* your "useful stuff" will actually go down.
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Re:just send the engine into the Sun (Score:2)
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OldMugwump blathered:
Sending things into the Sun is not at all easy. You'd have to cancel the entire solar orbital velocity of whatever it is you want to send there.
Oh, please.
All we'd have to do is to cancel a relatively insignificant part of its orbital velocity - which is to say "accelerate it to escape velocity for the Earth-Moon system's gravity well, in the opposite direction of that system's orbit around the Sun" - and let Sol's gravity do the rest.
What we don't have to do is to fire it directly into our star - which is what you're erroneously claiming. If we cancel enough of its solar-orbital velocity to let it fall toward the Sun, and it
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If we cancel enough of its solar-orbital velocity to let it fall toward the Sun, and it will eventually end up there. Who the fuck cares if it takes decades, or even centuries, to get there?
How many decades before Mercury falls in the sun, you reckon ?
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It is amazing how much confidence some people have in their incorrect understanding of orbital mechanics. It can't be from playing Kerbal Space Program either, because the fudging they use doesn't produce unrealities anywhere near this bad.
Do you imagine that as soon as you "escape Earth's gravity well" you start spiralling into the sun? Like Earth is somehow holding everything up from the irresistible sucking gravity of the sun?
Re: just send the engine into the Sun (Score:2)
ceoyoyo sneered:
It is amazing how much confidence some people have in their incorrect understanding of orbital mechanics. It can't be from playing Kerbal Space Program either, because the fudging they use doesn't produce unrealities anywhere near this bad.
Do you imagine that as soon as you "escape Earth's gravity well" you start spiralling into the sun? Like Earth is somehow holding everything up from the irresistible sucking gravity of the sun?
No, numbskull, I imagine no such thing.
Do you imagine it's possible to deorbit a payload into the Sun without first accelerating it to escape velocity from the Earth/Luna system's gravity well?
I didn't think so.
Now that we're agreed on that point, do you believe it's actually possible to accelerate that same payload to escape velocity from Sol's gravity well employing less fuel than it would take to slow its orbit around our home star enough to ensure it would eventually fall into the Sun?
Ye
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Ah, you found that StackExchange discussion! You must have found it while you were desperately trying to find some way of spinning your post to make it sound like it was actually correct.
Unfortunately, you've got this line:
When
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Well, as cool as it was, NERVA was cancelled because there was no mission for it and so no reason to spend more money on it. By the time NERVA got towards a test flight in the early 70's it was clear that there was not going to be any multi-billion crewed Mars missions any time soon. Apollo was nearly over with the last three landings cancelled so there wasn't going to be any gigantic lunar exploration followups either. So, a shame to cancel it, but continuing to spend taxpayer dollars would have been th
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Dump nuclear waste on the Sun? Sounds like a right-wing plot to prop up coal by tainting our clean solar energy with radiation!
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Also, nuclear fusion (not fission) could indeed be used to launch rockets.
Nope. The only way to get into orbit using fusion is: launch a big bomb under your ass and say your ass good bye.
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Because fusion as we do it only is either a bomb or a near vacuum plasma. A near vacuum plasma does not work that well at atmospheric pressures (and requires a reactor far beyond the size and weight of a missile).
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Hi - You mean conventional nuclear power? Or fusion?
I was a newly minted nuclear engineer the year that Three Mile Island happened. That event caused me to realize that companies cannot be trusted on Earth with nuclear power, so I quit my job, went back to school, and changed my career.
But in space things are different. It is not a closed ecosystem. And the value of nuclear energy for rocket propulsion is enormous. On Earth, we have viable alternatives to nuclear energy: solar, etc. In space, if you want to
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so long to pipe dream (Score:2)
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Too bad we don't make nuclear fuel anymore and Russia won't give us any anymore.
That's fine. We'll just buy, or take, the fuel from Iran.
And before you even ask, no, I am not serious.
Reaction mass (Score:2)
Thinking science fiction for a minute, surely you could use anything as reaction mass if you could vapourise it in the nuclear core - so random rock would do nicely. You just need a containment vessel / heat exchanger for the nuclear reaction with a higher melting point. The current best material I found on the web is tantalum hafnium carbide (Ta4HfC5), a refractory compound with a melting point of 4488 K (4215 C, 7619 F).
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Oh I agree you can achieve thrust without high temperatures, a rail gun or other electromagnetic gun would do nicely. I am concerned about the efficiency of the engine. The highest efficiency is achieved when the velocity of the departing reaction mass is the highest.
I was thinking that molecules at a high temperature are probably the fastest thing you can make to throw out the back of your rocket but perhaps I am wrong and an electromagnetic gun would be more efficient? What is the velocity of the molecule
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Molecules in the gas phase - well you're talking about under about 4000K there (things like titanium dioxide start to show up in the spectra of cooler stars). At 4kK, hydrogen moves at 223m/s, while TiO2 moves at 32m/s (and for comparison, U235 and U 238 at 20.61 and 20.47 m/s respectively, providing the basis for the industry of uranium enrichment). Of course, you can use pressure to incre
Green energy rockets (Score:5, Funny)
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That whooshing noise you just heard was the sound of the joke going over your head.
To the GP: Well played. Well played indeed!
Size and amount? (Score:1)
Not just energy for a huge new thermionic converter.
ie nuclear electric propulsion? eg a huge Kilopower https://en.wikipedia.org/wiki/... [wikipedia.org]
Re: In light of the Boeing massacres (Score:3)
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