Sealed Nuclear Reactors and Private Atomic Rockets.

My point is that if sealed self contained NTR cores could be built, then private ownership, and eventually possibly homebuilt launchers could become possible. I was NOT talking about home-building the reactor just as most homebuilt airplane makers don't build their own engines.

Legality aside, I would never attempt to build a reactor without being a nuclear engineer, and realistically, considering the laws, I would never do it at all.

These tiny sealed electric-power reactors do exist. I mis-remembered the point to which they were used but many isolated communities are looking at them, and some may be installed already, and will be in about 5 years.

Although NERVA had low thrust, DUMBO had much higher thrust to weight ratio, by far. And some other less developed NTR ideas have even better t/w.
One solution to the overly heavy LH2 tank problem is to use methane fuel. The specific impulse is not as good but much better than methane/lox chemical. (because the methane decomposes. Artificial dense decomposing fuels might be even better) The soot cloggup is a problem though. Maybe a stirred pebble bed reactor? Or puffs of oxygen, a bit like a LANTR?

The person who came up with the Liberty Ship seems to think that nuclear lightbulbs can have greater than 1 t/w. He might be wrong.


Just a thought: What if the fuel was solid, like frozen methane, that was heated and melted into the reactor? This is probably more for interplanetary travel, but it means very light tanks, or none at all. The "push up popsicle rocket".

Zubrin has an idea for a nuclear, lox-afterburning aerospiked SSTO.

Is there + any electric propulsion capable of earth liftoff? Or any other near term tech besides NTRs? (I'm counting strictly rockets, scramjets, etc. Not space elevators and the like)


Do you think that the autonomous sealed reactor could be applied to NTR cores?
 
Assuming it's real, a few grams of nuclear material is hardly a nuclear reactor.

If that's what you consider a nuclear reactor, then I built one in school in my experiment class...

It was real, there was a book written about it. Fascinating story. The kid was crazy smart but didn't have any common sense.
 
The kid was crazy smart but didn't have any common sense.


The average scientist then, huh? :lol:


Jokes asside...

ikrase: You seem to suggest that with a ~100 MW thermal power nuclear reactor, a SSTO would become a possibility for a backyard project. The cost of the 75 MW thermal power reactor seems to be in the 25 to 30 million dollar range. Assuming that with research and mass production, we can get the cost down to... what? 5 million? That's still not exactly within the financial capability of your usual home made plane builder type... not to mention the remainder of the vessel...

Home built planes are confined to mainly small sports planes. You don't see peeps building 747's in their back yard.



Private companies? Well, if we can straight out the politics, then I'd say that's a possibility. Though a strict control of nuclear fuel would be needed...

Evil lies implicit in the gift of enlightenment...
 

According to that article, the nuclear lightbulb gets a 10:1 thrust/weight ratio, gets an Isp of 3060s (with a theoretical max of 5000!), and that seven such engines could be used to lift a 1000-ton payload reusable SSTO booster to LEO!

Sounds very optimistic. sputnik's post above seems to be in conflict with that.

Also interesting in that article is that the author says nuclear lightbulb reactors were tested in the 60s and 70s, which I was unaware of. I alwasy thought the NLB was only theoretical. Cool that they have real test data on them.
 
5 million... That's way too much for homebuilt, but not bad for commercial space lift. I wonder just what the absolute minimum cost is, and have read of a technology which would allow huge amounts of nuclear fuel recycling.

If the fuel was something requiring enrichment to make a bomb, and the test firing of each reactor was long enough that it would be hot inside, fuel theft would not be a risk.

I think that many advanced engines are optimized for specific impulse, not thrust. In fact, the only high thrust engines I know of are chemical, Orion, NSWR, and NTR. If we were willing to make nuclear takeoffs, we would put more research into making high thrust engines, and DUMBO did have pretty high thrust.

Do you think there is any cheaper advanced engine for space lift?
 
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I guess that homebuilt atomic rockets won't work but it occurs to me that rockets need not take off vertically (and horizontal takeoff rockets seem easier to build if the mass ratio does not need to be huge.) Most airplanes do not have anything like more than 1 thrust to weight. It seems like the problem of atmospheric radiation scattering can be solved by not using the fuel around the reactor until out of the atmosphere, and one could have SRB's, a jettisonable reusable jet engine pack, or just "plane" rocket takeoff from a runway. You only need T/W > 0 for a short time. (consider the space shuttle.)

on the other hand, does 52 tons sound like insufficient dry mass not including the reactor for a ~170 ton GTOM SSTO? It's for a rocket with a single DUMBO engine.

I wonder if the TPS can also be the shadow sheild. Sounds too retractably complicated.
 
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Sorry, but a homebuilt/home operated spacecraft is NOT going to happen. There is simply too much red tape involved in the operation of such a dangerous vehicle. I can see rare cases of extremely rich individuals operating their own small spacecraft, but not much more then that.

It isn't a matter of technology. I could have a fully functional and ready-to-fly X-wing in my backyard right now, and I would not be able to fly it legally. An orbital spacecraft poses a danger to people on the ground, especially if the nuclear powersource somehow fails.

SSTO was possible in the '60s with inefficient fuels, btw. The problem lies within making a viable, reusable SSTO.
 
I meant that it was impractical. (ssto w/ chemical). Too big of a mass ratio. As far as aero and structure and TPS go a NTR w/ MR 3 is probably much better than 20 for chem as reactors are tiny.

I doubt that it will be soon, but judging by Suborbital stuff, homebuilt spacecraft are possible eventually and once some people start building those kinds of things, the laws would slowly change. (I mean corporations, etc). Or, it might get to the point where it was legal and possible to build one, someone would, and then laws would change that way. Although the Kzinti Lesson is a problem with anything hotter than NTRs.
 
Reactors are never tiny. They are either large, efficient and mildly safe, or small, inefficient and unsafe. This is a pretty constant thing in nuclear reactor design, radiation does not like small turning radii.

And what about the dry mass? Nuclear thermal rocket engines are HEAVY and have a rather poor thrust-to-weight ratio themselves. They reach high thrust, especially with LANTR, not the engine mass remains high at the same time.

Also, your ranting about chemical rocket engines contains a lot of inability to put things into perspective.
 
The problem is technology that would make backyard spacecraft a possibility would also make backyard ICBM`s even more easy. The governments would be VERY reluctant to allow such technology to filter down to a point where anyone with some money and knowledge could build an ICBM. Even if aneutronic fusion or some other yet undiscovered power source makes SSTO spacecraft relatively cheap to buy and operate it`s still likely to remain strictly controlled technology at least as long as there are crazy lunatic people in the world.
 
This thread reminds me of the time I tried to build my own atomic bomb at the age of 10...

I had decided for myself that I won't do nuclear fission before marriage.
 
It would also make anti-ICBM interceptors easy?

While not ever exactly tiny perhaps, NTR reactors save a large amount of space of balloony fuel tanks, and DUMBO did have high T/W. Making a re-usable vehicle with balloony fuel tanks is difficult due to TPS issues, and aerodynamic force issues. An NTR is much smaller than the fuel that it would replace by lowering the mass ratio.

If something was impossible to tightly control, it probably would become legal eventually. You could not control airplanes today short of outlawing private machine shops and look what happened to the IRS building!
 
Yet flying a nuke tipped rocket into an area will do more damage than a plane. It'd be a dirty bomb not a nuke but the damage would still happen.
 
You mean NTR or containing a nuclear bomb that misfired due to interception? Seems like if it survivies reentry, it could only be so bad. Plutonium is not anywhere near as bad as fission products, uranium almost a non-toxin.
 
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