UK Nuclear Spacecraft Could Halve Time of Journey To Mars (theguardian.com) 145
British spacecraft could travel to Mars in half the time it now takes by using nuclear propulsion engines built by Rolls-Royce under a new deal with the UK Space Agency. From a report: The aerospace company hopes nuclear-powered engines could help astronauts make it to Mars in three to four months, twice as fast as the most powerful chemical engines, and unlock deeper space exploration in the decades to come. The partnership between Rolls-Royce and the UK Space Agency will bring together planetary scientists to explore how nuclear energy could be used to "revolutionise space travel," according to the government. Dr Graham Turnock, the chief executive of the UK Space Agency, said using nuclear power in space was "a gamechanging concept that could unlock future deep-space missions that take us to Mars and beyond."
We had nuclear rocket technology in the early 70s (Score:5, Informative)
https://en.wikipedia.org/wiki/... [wikipedia.org]
Those nuclear rocket engines were much more powerful than chemical rockets - Higher Specific Impulse and Total Impulse.
My father actually did some work on them.
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Yes, this is what we should be pursuing for manned missions, not chemical rockets. Cutting travel time in half or more is extremely valuable. Supplies, shelter and tools could be sent on the chemical slow boats years before in preparation for a fast traveling manned mission.
Also should be researching fission fragment rockets, could power a probe to a few percent of C and get to another star.
Re:We had nuclear rocket technology in the early 7 (Score:4, Insightful)
Cutting travel time in half or more is extremely valuable
It is...except Starship is already being designed with a "three to four months" trip time in mind, and with no nuclear shenanigans to boot.
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Thanks to refueling. Orbital refueling is more valuable than nuclear rockets, at least for the moment.
Re:We had nuclear rocket technology in the early 7 (Score:5, Informative)
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You'll need to send a nuclear reactor to Mars.
"It's a bypass. You've got to build bypasses."
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However a nuclear rocket with orbital refuelling would be the absolute killer application.
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it's a pipe dream, fuel depots everywhere and a fuel production facility on Mars. Nuke rocket doesn't need that.
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Nuke rocket doesn't need that.
Nuke rockets don't need working mass? Are you sure?
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A nuclear rocket can take its working mass from earth for interplanetary round trips. A chemical rocket can't.
And if a nuclear rocket had liquid or gas core the Ve gets even huger, up to 50 km/sec for gas core. Or beyond that for fission fragment a nice percent of speed of light even.
Chemical rockets aren't the way.
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A nuclear rocket can take its working mass from earth for interplanetary round trips.
None that we have can do that. Solid core NTRs just aren't *that* performant. Gas core NTRs perhaps are but those are a pipe dream, and quite likely to remain so.
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what we have or did have were engines on test bed; round trip nuke rockets have had some level of design only but of course I could say no chemical rocket infrastructure for Mar round trip exists either.
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also should add the nuke rocket gets to cheat, not fired from ground but from being assembled in orbit.. with chem rockets of course
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A nuke needs fuel as well. ... uh ... oh ... it is a nuke?
Or do you think it just flies because
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...and shit propellant density, so that for your higher total impulse you need implausibly large tankage.
Liquid hydrogen. The Space Shuttle managed to get to orbit strapped to that "implausibly large" tank. What's the problem?
Nobody is suggesting nuclear thermal for boosters, but it works for second stage and excels above LEO.
We should have had nuclear thermal decades ago for Mars missions, instead of waiting for launch windows on slow-boats every 780 days.
Now we should be working on nuclear-electric ion drives. One thousandth of a G would be enough for interplanetary flight, say 1000N thrust for a 100 ton
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Liquid hydrogen. The Space Shuttle managed to get to orbit strapped to that "implausibly large" tank. What's the problem?
As I said, density. No, that was hydrolox -- not liquid hydrogen -- in that tank. Hydrolox in the tank was five time as dense as hydrogen would have been, and even twice the Isp of nuclear-heated hydrogen wouldn't have been able to get the orbiter to orbit. Delta-v for the Shuttle with 20 tonne payload and the SLWT was around 8.55 km/s. With your hypothetical "nuclear orbiter" and one fifth the mass of propellant, it would have been only 6.75 km/s. Not sure how you'd consider a 1.8 km/s shortfall an improve
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With your hypothetical "nuclear orbiter" and one fifth the mass of propellant, it would have been only 6.75 km/s.
Working? If we convert the Shuttle tank to pure H2, it should hold 150t - OK, that matches your 1/5th. With a reduced launch mass 300t, final mass of 120t and a 9.0km/s impulse, I get 8.4km/s delta-V. But with launch mass well under half that of the hydralox shuttle, there is going to be a much greater delta-V from the boosters. If there is still a shortfall, Kerbal taught me to just strap on more boosters.
Of course, I've ignored the thrust-to-weight problem, and strapping solid boosters on the side o
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Damn! 2 seconds after submit I realise I counted 30t of propellant in the orbiter.
With a mass ratio of 270/120 tons and 9.0isp I we get 7.3km/s delta V.
Might need to stretch that tank 25%, but on the plus side, no bulkhead needed and can use thinner walls due to lower propellant mass.
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The DV is not related to the payload.
No idea about your tank scenarios, does not mater if you have two taks, one for liquid hydrogen and one for liquid oxygen, or a mixed one.
(I doubt anyone ever was so braindead to mix liquid hydrogens and oxygen in a tank already, though)
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The parent said the shuttle had a mixed tank with lox and liquid hydrogen.
Did you answer to the wrong person?
NTR scenario outside of LANTR.
Is it so hard to not use abbreviations everyone has to google?
Where to discard it ?? (Score:2)
Now suppose you use this tech to go to mars, and back.
3 main risks
- exploson of the (conventionnal) launcher on the launchpad or in low athmosphere. Huge quantities of non-activated fuel are dispersed. Very bad.
- accidental re-entry of the used rocket into mars: activated fuel burns up, extreme contamination of mars
- accidental re-entry of the used rocket for the back voyage into earth: activated fuel burns up, extreme contamination of earth
How will we discard and stay away from such extremely dangerous wa
Won't happen. (Score:5, Interesting)
Rolls Royce is in serious trouble right now. They are still on the hook for the 787 engine troubles, they don't earn any money with their power by the hour program thanks to the coronavirus, they sold their power generation branch to Siemens, they fell behind technologically compared to GE and have been forced to freeze the development of their next generation ultrafan engine due to a serious lack of funds. I won't be surprised if Rolls Royce wouldn't survive 2021.
Re: Won't happen. (Score:3, Insightful)
The UK government wouldnt let RR fail, it's a major UK defence contractor. And now we're out the EU it can be given state aid or as a last resort nationalised and no one can prevent that.
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The UK government? You mean Alexander Boris "fuck business" Johnson?
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You vastly over-estimate the impact of leaving the EU.
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Not only that, the UK-Japan trade agreement has, in fact, stricter rules on state aid [ft.com] than the EU asked for.
Re: Won't happen. (Score:5, Insightful)
Not only that, the UK-Japan trade agreement has, in fact, stricter rules on state aid [ft.com] than the EU asked for.
An obvious solution is to camouflage the aid as boondoggle contracts for stuff like nuclear rocket engines.
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Bingo. This is just the Tories giving RR some free money, all they need to do is a bit of paper R&D before concluding it's a waste of time.
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Why yes. Woodburning engines are totally the future of deep space missions.
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But will they be in metric or imperial?
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But will they be in metric or imperial?
UK is totally metric. Except for some odd exceptions they cling to for sentimental reasons (beer pints and road miles), none of which affect engineering. They are not stupid.
Beer pints affect engineering ! (Score:2)
>> (beer pints and road miles), none of which affect engineering.
Infact, beer pints affect engineering !
If an engineer drinks a pint of beer, the rocket goes to orbit.
If an engineer drinks a liter of beer, the rocket explodes.
Re: Won't happen. (Score:2)
BS. It's far more limited than the EU rules and only applies to specific areas. Both you and that so called "journalist" need to do more research on the deal.
Re: Won't happen. (Score:2)
Not for state aid my friend.
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I am just waiting for the screams of outrage from people like you when they realize just how much influence the EU still has over the UK and how little control the UK has now.
I am also waiting for the outrage when people going on holiday in Spain realize that they have to buy medical insurance.
And, today, I see that the fisheries deal is making things worse for UK-based boats and may drive many out of business.
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To address this directly, did you perhaps read the news that Airbus was suing Boeing over state aid to Boeing? Since the USA is not in the EU, please explain how this is possible, but it's not possible for the UK's trading partners to sue over state aid to Rolls Royce?
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And? A european court can rule all it likes, it has no authority in the US and vice verca. Have you just brought a bridge for sale?
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Are you trying to be cute? It is a WTO lawsuit and the USA lost it. [wto.org]
Re: Won't happen. (Score:2)
Watch them ignore it.
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It's going to be like the 1950s all over again.
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Not really. There is a reason why Boeing chose GE for their newer 777 versions and the 747-8. On the 787 the GEnx engine has a slightly better fuel burn on longer missions thanks to its higher pressure ratio, is also more reliable. Even Airbus tried to get the GE engines for the A350 and the A330neo, but GE refused. And unlike GE, Rolls Royce has nothing to offer for narrow bodies.
Rule Brittania (Score:5, Funny)
One thing you Yanks have forgotten is that there are no space dentists on Mars. Doesn't bother us brits.
As long as we don't run out of space tea and warm space beer.
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As long as we don't run out of space tea and warm space beer.
lol -- as long as you don't let Lucas subcontract any of the parts, a brit rocket should be just fine. (We know why you guys like warm beer -- you all have Lucas refrigerators...)
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Spot on, +1
I want an Orion spacecraft (Score:3)
But not in my neighborhood.
orbit contamination (Score:2)
In this case "Not in my solar system".
Seriously, anything you use contaminate earth or mars orbits will collide back with those planets over time and pose big radiation problems.
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"In this case "Not in my solar system"."
That's my neighborhood. :-)
Again? (Score:2)
What a hyperbole. (Score:2)
OK, so we have: ..."
"... British spacecraft could travel to Mars in half the time it now takes by using nuclear propulsion engines built by Rolls-Royce
Yet the article later specifies:
'... “This study will help us understand the exciting potential of atomic-powered spacecraft, and whether this nascent technology could help us travel further and faster through space than ever before,” he said.'
Well, I'd be glad to see some development of nuclear space propulsion, but the headline can clearly stat
Take off safety (Score:2)
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Not a dirty bomb, reactor doesn't have to be critical before launch, could be non-activated fuel that would only give off alphas. After a reactor is made critical for first time and run in space then yes, fuel becomes a dangerous neutron and gamma emitter even after shutdown. But then no one on the ground needs to care.
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Dirty bombs aren't a thing. I'm sure they make great plot devices but they are terrible devices for war or terror.
The more radioactive something is the shorter it's half life. Which means blowing up a dirty bomb involves first accumulating something highly radioactive, which will be highly dangerous to the people making the thing. Then they'd have to attach it to something explosive. That's hard as well because any electronic timers or triggers will be eaten up by the radiation, as will the explosive ma
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> . Which means blowing up a dirty bomb involves first accumulating something highly radioactive,
It's the same material as a "clean" bomb. Neutron bombs are typically based on reducing the yield of the weapon, shielding it less effectively and allowing more of the neutrons from the weapon to escape the shielding that helps concentrate the explosion. It's notably _easier_ than an efficient, clean nuclear weapon of maximum yield.
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A neutron bomb is something different than a dirty bomb. At the core of a neutron bomb is a conventional explosive but it is carefully constructed to trigger a fission explosion, the neutrons are then used to irradiate the area and lead to large numbers of people to get sick and potentially die. A variation on this uses the neutrons to transmute some stable element into some highly radioactive element, which is then spread through the environment by the explosive force of the fission core. This is called
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I would call a neutron bomb a form of dirty bomb, focused on fallout. I see your point that the Wikipedia definition does not equate them. I'd call the distinction one of degree, not of type, and certainly any fission bomb involves "accumulating something highly radioactive". Either is notably easier to build than a modern atom bomb, and built of much the same materials.
> a nuclear thermal rocket than undergoes a rapid unscheduled disassembly on lift off will not produce any fission
Have you seen any nucl
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I would call a neutron bomb a form of dirty bomb, focused on fallout.
I guess there's plenty of similarity in their intended result but they are quite different in function.
certainly any fission bomb involves "accumulating something highly radioactive".
No, a fission bomb does not involve accumulating highly radioactive material. The uranium and plutonium used in nuclear weapons have half lives in the thousands or millions of years, and the primary decay modes are alpha and beta decay. They pose very little radiation hazard and would be worthless in a dirty bomb.
Either is notably easier to build than a modern atom bomb, and built of much the same materials.
A dirty bomb is quite simple to construct, it's just conventional explosives wrapped in some
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Solar sails could do well, do not require handling nuclear materials in bulk in new environments, and are far safer to test. The low thrust from light pressure and/or solar wind is continuous, and far safer to build, than nuclear engines. There are many good articles about the approach, including:
https://iopscience.iop.org/art... [iop.org]
https://ntrs.nasa.gov/citation... [nasa.gov]
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Solar sails could do well,
Obviously not well enough, otherwise nobody would consider nuclear thermal rockets. Solar sails are still theoretical while nuclear thermal rockets use technologies that are well understood and were proven feasible 50+ years ago.
do not require handling nuclear materials in bulk in new environments,
Irrelevant. Space travel already involves dealing with radiation, nobody is going to care much about radiation from a nuclear thermal rocket engine. What also makes this irrelevant is that any manned mission to Mars is going to have a nuclear reactor for power. They will no doub
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Nuclear rockets got significant research because of their military possibilities. A rocket whose energy source could last for years without topping up is appealing. So is a rocker the enemy dare not shoot down without causing nuclear debris. And no, the fuel in a nuclear rocket is _not_ safe. Unless the rocket is very low thrust, it has to have enough fuel concentrated enough to provide chain reactions. Not enough to go critical, but enough to enhance the radioactive output of its core and improve the mass
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It's Mr. Hallucination again!
Dirty bombs are perfect weapons for war and terror, eh? Can you describe how they function? How big must this city killer weapon be? What is it's mass? Will it fit in a typical bomber aircraft? Can they be dropped from a smaller aircraft like a F-35? Or are these so large that they can only be dropped from a cargo plane like the GBU-43/B (aka MOAB)? What radioactive element or elements do they disperse? Are these elements alpha, beta, or gamma emitters? What is the half
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Dirty bombs are perfect weapons for war and terror, eh? Can you describe how they function? Google it.
Looking at your other posts in this threat, you have no clue about anything. Not worth discussing with you.
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I'd assume they'd be assembled in orbit for just such reasons.
Yes, M'lady (Score:2)
Is this the nuclear salt water engine? (Score:3)
Scott Manley recently talked about the fascinating nuclear salt water engine: https://www.youtube.com/watch?... [youtube.com]. Also https://en.wikipedia.org/wiki/... [wikipedia.org].
Fascinating stuff. Unlike most proposals including the idea of detonating nuclear bombs behind the spacecraft, this one is actually feasible. It's a brilliant idea. And it's super efficient. Way more efficient than chemical propulsion. I think it's right up there with ion propulsion, except that it's on a much bigger scale (way more thrust obviously).
Obviously something like this wouldn't be used in the atmosphere. But out in space it would be just fine.
Like most nuclear things, though, fear of weapons-grade enriching has and will stifle its development.
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I saw that the other day and when I saw this I immediately wondered if it was great coincidence, but the article is lacking in details in terms of what the UK wants to do.
I know when I saw Scott's video though, I immediately realized that we'd never be able to reasonably launch these vehicles on Earth. I think its more likely these Nuclear engines are launched from the Moon or maybe a high Earth orbit. Maybe you mine the Uranium on the moon, if there are veins available and build the engines there. Either w
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Low earth orbit would be fine. The exhaust has such high velocity that it would leave earth's orbit if what Scott said is true.
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I also really wish that the article had more detail. "nuclear rocket" could mean a whole lot of things, from nuclear thermal rockets, (probably what they're talking about) to nuclear salt water, to Orion, to... technically, if you put an RTG on a craft with an ion thruster, it's a nuclear powered propulsion system, and both of those are currently fielded, though I can't find a single craft that uses both.
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Yes it's theoretical. But at least it's also feasible. Wikipedia says there's still uncertainty as to whether the water flow can really hold back the neutrons and the reaction from destroying the inside of the engine. Would love to see it tested!
diff between halve and half. (Score:2)
Re: I'd like to see.... (Score:5, Informative)
I dont think they're planning on throwing radioactive material out the rocket nozzle you clown. The nuclear reactor simply provides massive heat energy to a propellant, its not a nuclear bomb.
Re: I'd like to see.... (Score:5, Informative)
They are. Current viable nuclear thermal rocket designs are all open cycle, meaning that the hydrogen that you accelerate comes into direct contact with the nuclear fuel, and takes the fission biproducts with it. Closed cycle designs are theoretically possible, but no one really works with them because they have lower Isp.
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That makes zero sense. Shielded uranium releases as much heat as if it were unsheilded. Unless you think the heat somehow gets stored in the material? The only issue is finding shielding that can survive the heat.
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I dont think they're planning on throwing radioactive material out the rocket nozzle you clown. ... its not a nuclear bomb.
For now, that is true. But if you really want to go fast, maybe even send probes to other solar systems, you need a *real* nuclear rocket, which in NSFE. (not safe for Earth). Two types have been proposed:
Nuclear salt-water rocket [wikipedia.org]
Project_Orion_(nuclear_propulsion) [wikipedia.org]
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Nice Theory.
Problem is: Once the launcher explodes on the pad, you have a big wasteland around you.
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FML does one really need to explain on /. that a nuclear pile/generator/plant *is*not*a*nuclear*bomb*?
Re: I'd like to see.... (Score:2)
But nuclear material near a combination of potentially explosive chemicals is potentially a dirty bomb. Even if it looks like a chemical rocket launching a nuclear rocket.
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No, it's not a potential dirty bomb. Not even close.
A dirty bomb is a weapon that poses a radiation hazard to people that enter the contaminated area. The fuels useful for a nuclear thermal rocket would be either uranium or plutonium. Uranium is a naturally occurring element so if it's spread about by a chemical explosion then it's going to be really hard to even find the radioactive rocket bits from the naturally radioactive bits. If there is plutonium in the rocket engine then people might be able to
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It would mean radioactive material from Earth gets shot into space. So it's gone from our planet's environment and that's a plus.
If it then burns up in the vacuum of space into gas and dust (at a certain distance away from Earth ofc) then the solarwind will carry it to the edge of our system by which time it will have distributed and stretched out so far that it won't stand out against the constant storm of charged particles coming from the sun itself.
But knowing mankind will we use it far more often than w
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But knowing mankind will we use it far more often than we should and create problems just because we can, and ignore it, to leave it for another generation to fix.
Right. I just look around and see everyday how fucked up the world is from all the mess left by generations before. Except it's not like that at all.
If people think the world is going to get worse then I'm guessing it's because they are expecting to make it worse themselves. Nothing predicts the future better than making it. If you believe your generation is making things worse for the next then it's because YOU are making things worse for your children. You are projecting your own bad behaviors on oth
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Except it's not like that at all.
So you're blind. What else is new?
https://www.theguardian.com/en... [theguardian.com] ...
https://www.sciencealert.com/h... [sciencealert.com]
https://www.scientificamerican... [scientificamerican.com]
https://www.forbes.com/sites/j... [forbes.com]
https://www.elitereaders.com/d... [elitereaders.com]
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I don't think there is a space agency that has a perfect launch record. One of the risks with launching a payload are the consequences if it fails at various stages of launch. Each is a different consideration bet it a disaster at the launch pad, sub-orbital, and at high orbit. The amount of material that could be dispersed, and where it might land is also a consideration. A relatively small radioisotope decay power module ("atomic battery") is a different level of consideration than an nuclear propulsion m
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Indeed. This is another reason we need fusion reactors.
Re: *RED ALERT!! RADIATION POISONING!!* (Score:2)
Thereâ(TM)s a point at which specific impulse doesnâ(TM)t matter hugely though once itâ(TM)s easy to get fuel in space. I mean, Iâ(TM)m not opposed to more efficient vehicles, but Iâ(TM)d much rather see us send up 3 tankers with methane & oxygen on board than send up rockets that could spread radioactive uranium across the earth. I personally donâ(TM)t believe that the 1 in 250ish rate of major failures of nuclear reactors that weâ(TM)ve had on earth is acceptable,
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if you can make fuel in space, you're in really good shape in terms of economics. But you still need to carry a lot of fuel to go to Mars and back, even if you get to start from Earth orbit with a full tank.
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You are worried about "rockets that could spread radioactive uranium across the earth"? I'm sorry to inform you that there is already radioactive uranium spread across the earth. Where do you think uranium comes from? We dig it up out of the dirt. If a nuclear rocket blows up on it's way to space then it will just return to earth the uranium that was dug up from it. Any sane nation launches rockets over water so that if there is a failure then it's not likely to hit anyone or start anything on fire. I
Re: *RED ALERT!! RADIATION POISONING!!* (Score:2)
I think it comes from centrifuges that hugely refine the uranium we dig up from the ground, and that itâ(TM)s hugely more concentrated both in terms of the contents being Uranium not rock, and in terms of the isotope in there being radioactive. Dropping chunks (even small) of nuclear fuel back to earth is a terrible plan!
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Those small chunks of nuclear fuel can not contaminate the planet any more than it already did when it was in the ground in the first place.
Consider the pollution from something like chlorine gas such as used in World War One. The military would create this gas from salt they mined. Then they release it on enemy soldiers to kill them. That was indeed a bad thing since it made an area deadly for a time. After the gas was released it would dissipate, get "washed" out of the air by rain, then eventually re
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I think it comes from centrifuges
Stop thinking then, and do some reading from reputable sources. Enriched uranium is still not very dangerous.
Nobody was worried about uranium from Chernobyl - it was the fission byproducts such as iodine and caesium-137.
Coal smoke-stacks pour countless tonnes or uranium and thorium into the atmosphere. But they are not why coal smoke is bad.
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I avoid breathing the stuff when I can.
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Thereâ(TM)s a point at which specific impulse doesnâ(TM)t matter hugely though once itâ(TM)s easy to get fuel in space. I mean, Iâ(TM)m not opposed to more efficient vehicles, but Iâ(TM)d much rather see us send up 3 tankers with methane & oxygen on board\
This post shows you are as ignorant about rockets as you are on nuclear safety or using quotes in slashdot posts. (Try preview FFS!)
1) The rocket equation. Rockets are all about the "delta V".
For an interplanetary mission, suppose final mass is 5% of initial, you get around 10km/s delta-V from chemical. A nuclear thermal rocket engine can double that.
To do that with extra chemical propellant, you would need twenty times the initial mass, in reality that means an extra stage of twenty times
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A relatively small radioisotope decay power module ("atomic battery") is a different level of consideration than an nuclear propulsion motor with a significant amount of fissile material on board.
Sorry, but you have it arse backwards.
The RTG ("atomic battery") contains highly radioactive isotopes, but nuclear reactor fuel is barely active at all at launch, and would be harmless if dispersed.
Only once safely in space is the reactor started up, and begins to generate more radioactive isotopes.
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In space, speeding up and slowing down are exactly the same thing; It just depends on where you are pointing. There is one asymmetry in that you can use planetary atmospheres for braking.
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Depending on where you are going, you can plan the burn so you only accelerate and never decelerate.
burn up, or crash (Score:2)
you can plan to burn up, or to crash. :)
No need for fuel for that decceleration
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[previous comment that in some cases no decel needed]
you can plan to burn up, or to crash.
No need for fuel for that decceleration
Completely wrong. The solar system isn't a collection of objects with zero relative velocity. If you set up your path so that you have to accelerate to match velocity with your destination, then in the rest frame of the destination you are already "stopped."
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Heinlein described this, decades ago, as "delta V". His old stories described the trade-offs of time and fuel and energy and human lives very well: i highly recommend them for youngsters who need to appreciate the harsh limitations of physics, and of humanity.