Nuclear Propulsion - The best way for space travel

Josh Cryer · 2003-01-28 20:08:04

The supply and demand comment wasn't about nuclear power companies supplying to the consumer, is was about the nuclear material production companies supplying to the nuclear power plants. Think soph. If you had a lot of uranium or thorium mines (and processing facilities) supply would be great... it is always in a companies interest to curtail the efforts of another (by undercutting price and so on).

Giffen Goods are with regard to monopolies (usually natural- which power companies tend to be); obviously, if there is only one supplier as price rises, demand rises. If there is no other source for something [usually cheap and relatively important], where will people go? Supply and demand come into play (what I like to call Darwinian Economics) when there are many suppliers and no monopolies (ie, the real free market).

And as to the pandoras box, well, it's quite simple really. But first you have to accept that nuclear power companies aren't going to be mining a silly, laughable, 3kg a day. If it goes like I say it would (and it would, because I'm right- unless there is a rational govermnet mandate keeping producers from making more than Nkg a day for every contract,where N is how much the contractors need- in other words, a mandate keeping processed stockpiles from occuring), nuclear material poliferation would be great. The more nuclear material you have, the harder it is to keep track of it all. If there is a government mandate, stockpiles would be unprocessed material, but even then they would have to be guarded with care.

BTW, I should point out that processing of 1000 tons of raw ore per day (which I believe translates to around 2 tons of uranium- though this page where I'm getting this is unclear) in the 70's wasn't unheard of, so if we wanted to have this magical 3kg per day figure, we would need a mandate.

And yes, blah blah, I know that coal has a lower energy density than nuclear, we weren't debating that. We were talking about whether or not nuclear power companies would continue to mine regardless. You've failed to show that they would mine this laughable 3kg a day.

soph · 2003-01-28 20:13:30

There should be regulations, like there should be on any mining of any potentially dangerous material. Perhaps the nuclear stockpile could be centrally located and guarded, and siphoned off to regions who need it. Maybe the stockpile could be kept in regional locations, and distributed from there.

Josh Cryer · 2003-01-29 00:11:09

Certainly. A central distribution point would be quite profitable.

Put regulations all over the place, guards, security, the works. It's dooable. But once it's all in place, you gotta wonder if it's really more efficient than other forms of energy.

soph · 2003-01-29 05:40:54

the same level of ridiculous regulations that anti-nukes use to try to kill nuclear power? i dont think so.

fair and reasonable regulations, and the process will be quite efficient.

perhaps it could be guarded by the national guard like they guard our airports, at the governments expense, which is perfectly fair.

Josh Cryer · 2003-01-29 06:09:29

Um, what I said was fair and reasonable, I wasn't trying to exaggerate it, I was just contrasting it with biomass. You don't have or even require guards for biomass. In fact, it would be so decentralized, that towns could use their own policemen to check the facilities out ocassionally. The workers themselves would be more than enough to avert vandlism and so on. Biomass facilities would have to be no more guarded than say, a Wal-Mart.

John_Frazer · 2003-01-29 14:33:27

> It would be quite trivial to show cases where nuclear energy is just as evil as coal or other forms. The only truely benign energy source is solar. Anyone pretending otherwise is in major denial.

I've never heard an answer on the environmental impacts of widrespread solar: production of the cels involves metals leaching and etching, with lots of nasty runoffs. Do all solar cel makers take care of their wastes as well as the "green" packaging implies? What about disposal/recycling of dead cels?

I too favor solar cels on every rooftop and cartop, but covering the entire unused surface area of trhe continent isn't trivial, and how does solar & wind provide for the energy needs of a modern mobile industrial society?

Build nuclear plants to use up the economically mined U and Th ores, then build breeders to deal with most of the waste issues (getting more energy from reprocessed spent fuel than was produced spending that fuel).
Take the Pu end product from the breeders, and make thousands of identical atom bombs to be launched into space in special containment and loaded into Orion space ships (thus blowing our radioactive waste problem off into the solar wind).
These ships plant seed factories at NEAs and maintain interplanetary transportation infrastructure at least as long as needed to allow space resources and infrastructure to be proven, so they can start replacing power generation and transmission industries on the planet with Solar Power Satellite systems, and replacing heavy polluting industries on the planet with space industries. No more power plants, mines, or refineries on the planet.
Use SPS power to produce H2 from seawater, to react with atmospheric CO2 to make CH4 (natural gas) for consumer & industrial fuel needs.

Build nuke power stations and bombs, to save the planet from heavy industry!

> Bill White has it right on target. American interest in space in and heck, science in general, is at an all time low. It would take some sort of space race to get us interested in space again.

See www.marssociety.org for one organization which has the intention and stated purpose to kick-start exactly that. See Zubrin on public enthusiasm for Mars: the number of people who hit the NASA pathfinder mission website in the week the probe landed being greater than the number of people who vote -greater than the number of people actively either for or against a balanced budget, campaign finance reform, gun control, and abortion combined!
CBS bought the exclusive rights to the Atlanta Olympics for $2 billion... and see this article for more such ideas. "Those who think it's not possible should get out of the way of those who are doing it" --Chinese proverb

> John Frazer says that nuclear is basically necessary for routine [human] Mars travel. Though at the moment it may be true, I'm confident there will be solar breakthroughs which are cheaper, and more effective than nuclear, at least in the inner solar system.

With nearly 50% of the mass in LEO being cargo to Mars on a 6 week trajectory?!? Show a single shred of evidence for believing that kind of breakthrough is physically possible -with sunlight... (and I said routine, robust & rugged, above all rapid human space travel.)

> NASA has shown that they don't need nuclear to get the job done, and NASA has shown that probes are the best candidates for planetary exploration

Only because as you said, they've not made a large, goal-oriented human space program part of their goals.
Chemicals may be fine for sending probes on multi-year trajectories.
And probes are not the best for planetary exploration.
NASA did a study: planetologists studied an interesting and varied area of the Mohave and catalogued all the interesting finds and the conclusions to be made from that evidence. They next released several other teams of scientists to study that patch of desert through telerobotics. Truly dismal results.
Zubrin wrote that you can hardly hike through the Rocky Mountains without finding a good area to search for and find fossils, but you could drop a thousand rovers into the Rockies and they wouldn't find a fossil until the next ice age -and they wouldn't be able to outrun the glaciers.
Carol stoker did a presentation on this at the 1st M.S. conference: she showed images from Sagan Memorial Station (the pathfinder lander) showiwng some interesting geologicalclues the cameras could see. The rover had no hope of ever getting to these rocky outcrops a couple of km away, but a human could have strolled over to them within an hour of landing there.

clark · 2003-01-29 16:26:38

http://www.spaceref.com/news/viewnews.html?id=714

NASA Set to Unveil 'Jupiter Tour' Mission

When NASA rolls out its FY 2004 budget on Monday a large new planetary exploration mission will be revealed. The Bush Adminstration has signed off on a multi-billion-dollar-class mission dubbed "Jupiter Tour' - a mission which embodies a radical departure from the past four decades of planetary exploration.

Jupiter Tour would utilize a sophisticated spacecraft capable of multiple jumps from an orbit around one jovian moon to an orbit around another. Such a capability will allow close, detailed, and long-term studies to be made of many of the members of Jupiter's retinue of 40 (or more) moons.

The mission is slated for the 2009/2010 time frame and is expected to last more than a decade. Jupiter Tour will use an advanced nuclear-powered propulsion system developed under the umbrella of the newly-focused "Prometheus" program.

The cost of the program is projected to be at least $3 billion through Fiscal Year 2008.

Here it is, Project Prometehus, in all her glory.

Monday it wil be official

nebob2 · 2003-01-29 19:18:27

A NEP powered probe to Jupiter would be a great first step. Too many nuclear programs have faltered because they tried to move too far to fast (SP-100 for example). Once a succesful mission is acomplished, then we can move on to bigger and better things.

And after what Galileo brought back, a new mission could answer a lot of questions.

soph · 2003-01-29 21:23:55

Um, what I said was fair and reasonable, I wasn't trying to exaggerate it, I was just contrasting it with biomass. You don't have or even require guards for biomass. In fact, it would be so decentralized, that towns could use their own policemen to check the facilities out ocassionally. The workers themselves would be more than enough to avert vandlism and so on. Biomass facilities would have to be no more guarded than say, a Wal-Mart.

Yeah, but they will be much larger and less efficient per space taken up. You waste a lot of land. If we used the land needed to create 1,000 MW of power for nuclear plants, we could probably generate many times that, and recycle the fuel through breeders.

i never said you were being unreasonable. my point was that regulations are often taken far and away too far. yucca mountain material should be sent through breeders. i dont see how these environmental groups can protest high level wastes and breeders at the same time. its a circle of false logic.

TJohn · 2003-01-30 07:18:36

Quote: Here it is, Project Prometehus, in all her glory.

Monday it wil be official\

Will this be broadcast on TV somewhere or will it be posted at the NASA website?

Josh Cryer · 2003-02-05 03:51:09

I read the ISP of nuclear rockets is rather high, but that their maximum thrust isn't anything to be impressed about. Comments?

RobS · 2003-02-05 15:49:51

Actually, it's the other way around. The ISP of nuclear thermal rockets is much lower than ion engines (900-1000 seconds; now maybe they're talking about 1,500 seconds) but the thrust is much higher. Ion engines are lucky if they can make an ounce of thrust. The NERVA program in the late 1960s and early 1970s tested a nuclear rocket with, I think, 250,000 pounds of thrust. It's much easier to make heat than electricity, and thus all of the reactor's heat output can go to heating hydrogen and expelling it. But to make electricity you needs tonnes of generators and heat expulsion equipment and your conversion efficiency is 5-25%.

-- RobS

TJohn · 2003-02-13 14:52:44

There is an excellent article over at www.nuclearspace.com by Anthony Tate about the advantages of nuclear power use in space. In particular, the GCNR. I haven't seen anything about the Liberty Ship but it looks amazing. I'll have to do some searching and see what I can find.

TJohn · 2003-02-13 14:53:09

There is an excellent article over at www.nuclearspace.com by Anthony Tate about the advantages of nuclear power use in space. In particular, the GCNR. I haven't seen anything about the Liberty Ship but it looks amazing. I'll have to do some searching and see what I can find.

Gennaro of Scandinavia · 2003-02-15 06:08:49

Why nuclear reactor rockets?

The way a true amateur sees it.

Outside the magnetic field, the interplanetary medium is riddled with radiation. Massive Coronal Ejections take place several times a week. Not all are equally powerful by far, but the big ones will fry an astronaut standing on the Moon.

Evidently, interplanetary spacecraft require heavy shielding and other protective measures. Which adds to mass significantly. Which in turn calls for extremely powerful lift viechles.

You can't load a manned, several month mission spaceship into a shuttle (or equivalent), unless you plan to assembly it on top on the gravity well. How we do that in the foreseeable future? I doubt we possibly can. If we need some sort of 'shipyard' it will take orbital intrastructure which we probably will not possess for at least 50 years, the way our political system works.

In other words, a manned Mars spacecraft will have to be able to make it out of the gravity well on its own power. Thrust to weight ratio therefore is paramount, specific impulse less so.
From my, perhaps restricted viewpoint, if we want hardware readily available near-term, I really see no alternative to thermonuclear rockets. Advanced Ion drives are all very nice, but you cannot launch them from Terra Firma, because the T/W ratio is insignificant.

Maybe the VASIMR is an exception from this, or so I've heard, because of the ability to modify thrust, but I still doubt it would be enough to actually propel it off Earth. Essentially, it's a nuclear powered Ion drive. Perhaps someone in the Forum knows?

I think NASA has done a wise decision to reopen the file on nuclear propulsion. I suggest that ESA should do the same.

See you on Mars!

soph · 2003-02-15 08:03:02

Well, there is also the interplanetary "hybrid" option, NTP (NERVA type) and NEP (ion drive) spacecraft, that are capable of high thrust for liftoff, and interplanetary cruise, which allows higher isp. This gets you thrust when you need it, and saves you fuel outside of the atmosphere (a lot of fuel).

Gennaro of Scandinavia · 2003-02-16 16:06:39

Well, there is also the interplanetary "hybrid" option, NTP (NERVA type) and NEP (ion drive) spacecraft, that are capable of high thrust for liftoff, and interplanetary cruise, which allows higher isp. This gets you thrust when you need it, and saves you fuel outside of the atmosphere (a lot of fuel).

Sounds interesting. I'll go and see if I can find some reference to such a hybrid option.

soph · 2003-02-16 16:14:44

Hybrid

Phobos · 2003-02-22 18:16:32

Do we really want to launch nuclear powered rockets from the ground? I used to be a big supporter of the idea but I've been having second thoughts lately. Even though there's no doubt a nuclear rocket could be cheaper, more efficient, and all around better than a chemical based rocket, I just haven't been sold on the safety issue yet. At the very least if we do use nuclear rockets to launch from Earth, we should launch them away from major population centers, perhaps build a platform out in the ocean for the task. I do support unequivocally though the use of nuclear power reactors in space even though I think, as Josh Cryer mentioned, we'd be better off trying to develop more efficient non-nuclear power sources. Since I believe that private interests will be the ones to make spaceflight possible in a big way, and since they likely won't be allowed to use a lot of nuclear options, I think we might be better off trying to develop better solar cells and other non-nuclear power sources.

soph · 2003-02-22 18:18:59

You could launch from the sea, that is an option, or a coastal airstrip (i like that, easier to send payload over land, and an airstrip is easier to prepare), where the entire launch occurs over water.

Safety could be ensured, but to quell any fears, you could still launch over water, just to be more safe.

Josh Cryer · 2003-02-22 18:27:43

Hmm, replying to something John Frazer said.

With nearly 50% of the mass in LEO being cargo to Mars on a 6 week trajectory?!? Show a single shred of evidence for believing that kind of breakthrough is physically possible -with sunlight... (and I said routine, robust & rugged, above all rapid human space travel.

http://www.newmars.com/cgi-bin/wiki.cgi?Dusty-M2P2

Now, you asked for a shred of evidence. There ya go. Whether or not its feasible in the future, who knows. But the concept is sound, from what I understand of it.

if Dusty-M2P2, or Plasma Sails are feasible, then they would undoubtedly be the cheapest, easiest way around the interplanetary solar system. Not to say that nuclear wouldn't have a place.

soph · 2003-02-22 18:37:36

But then you have to deal with fusion Josh! Faster and more payload!

And the propellant for fusion is water, which incidentally makes a great radiation shield! Killing two birds with one stone!

I hope solar and magnetic sails work, but they will not have the same capacity as fusion, i think. As fusion becomes more viable and efficient, it will not only produce fast, high payload vehicles, but also a viable power plant.

Josh Cryer · 2003-02-22 19:26:51

Heh, M2P2 sheilds you naturally, since it creates a mini-magnetosphere. So shielding is certainly taken care of. I can envision small Dusty-M2P2 / Plasma Sail ships wich hold a few people, being used as quick transport vessels. (BTW, Sheldon calls them Plasma Sails, so I'll start using that term exclusively later on, I just want to make sure people know what I'm talking about.)

Fusion might be more efficient than M2P2, but that doesn't change the fact that M2P2 is extremely simple. You could potentially build an M2P2 engine from parts from Loes.

Just a glass jar, some metal bits, and a spinning magnet, and there ya go. The real issues, at the momment, aren't with building or designing the engine, but rather, finding the best particles which suspend the best within a mini-magnetosphere.

soph · 2003-02-22 19:48:45

Right, but how big does this sail have to be to get a large vehicle (100 tonnes or more) anywhere?

How much Delta V can it generate?

How far out in the solar system is the plasma sail effective (in terms of reasonable speed)?

How do you generate your power (a fusion reactor takes care of this itself)?

Josh Cryer · 2003-02-22 20:28:02

Depends on how good of particles we can get.

The Plasma Sail itself is effective to out to Jupiter, generally. But the magnetic sail could be effective for much much further than that, since it always has a constant rate of pressure.

Power can be generated from simple sources, you could use solar power if the sail was big enough. A superconductor could keep its field for a long time, without any power pumped into it.

Since the sail grows well, it doesn't matter how big it needs to be. You could have several of them, attached via carbon fibers or whatever.

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Re: Nuclear Propulsion - The best way for space travel

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