http://www.nuclearspace.com/images/gallery/ntr_to_moon_small.jpg

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Results so far! (http://pub97.ezboard.com/fnuclearspacefrm4.showMessage?topicID=263.topic)

Quite an interesting response to date. It's a graph illustrated poll with multiple choice answers including the infamous "Not Sure". For the life of me I have never understood why people bother to register and vote for that answer. Seems rather pointless but then humanity has been retrogressing awhile.

Lol... it's on a nuclear-space forum... what do you think the response will be;)

Anyway I put in for space only...

Assuming plentiful power:

1) Does it matter how quickly you get to escape velocity? Slower acceleration equals less stress on the craft and occupants.

2) Could a spacecraft match the Earth's rotation while maintaining altitude, and then de-orbit straight down, avoiding a traditional re-entry burn?

3) If 1 and 2 are feasible, could nuclear engines provide enough power for the above?

If 3 is true, then nuclear is the only way to go. The most argueable opposition I've seen against nuclear for LEO is what happens if a Columbia incident happens. Avoid the stresses of launch and return, and that threat is greatly minimized.

Does it matter how quickly you get to escape velocity? There is a lower limit... you have to be accelerating fast enough to maintain stability. My thing is that NASA wants to cold-launch nuclear engines. But that suggests that the engines are not designed to reach escape velocity in a reasonable amount of time.

Also, the use the fact that nuclear material has already been launched into space to make the public feel better about this. These were mostly small nuclear payloads in ceramic bricks (nuclear-batteries). There's a big difference between this and a nuclear reactor surviving re-entry.

"Anyway I put in for space only..." - Persol.

So that was YOU!!!

Actually, I thought it might have been Orstio as he is a bit like that. The result surprised the heck out of me. We get people from both sides of the fence dropping in over there. I thought the result might have gone the other way. I suppose it varies from day to day and the nuclear initiative has brought in a more optimistic crowd. We'll leave it up awhile. Space.com had a similar poll years back and it was posted at their messageboard but linked directly from the website. The results were similar but the response was huge. Hundreds of votes and something like 97% in favour of nuclear power for space. Ofcourse, that wasn't a typical cross section of the population either. Space cadets are a fringe group unfortunately.

So that was YOU!!!
::Persol looks behind himself guiltily::

hehe... is it actually feasible for one of these engines to safely provide enough thrust for takeoff? I don't see a way, but you're more involved in this group then I.

I'd like to find out. Wouldn't you? That top image is Nasa's rendering of a nerva type rocket more fully developed.

Quicksearch.

"Beginning in the 1980s, there was a renewed interest in nuclear rocket propulsion as a result of President Reagan's Strategic Defense Initiative (Star Wars ). The capability of the rockets to provide significant improvements in payload delivery was again recognized. (http://www.atomicinsights.com/sep95/rocket_programs.html)"

I've seen other references. Five times the usual payload possible today. Not just because of increased power but less fuel mass aswell. The energy is there. How far it takes us will depend on how innovative we can be. That means investigating it and some hands on engineering(and voting for the first option in the poll, lol).


The most argueable opposition I've seen against nuclear for LEO is what happens if a Columbia incident happens.

Looking over the list of fatal accidents and close calls over the last 42 years I have noticed almost all were a result of combustible chemical fuels exploding or an energy shortage. More power would mean more safety.

PEEEEEERSOL!

I have inquired of greater minds and have an answer of sorts to your question.

Stan Friedman sent this to me by email in response to asking about the possibility of nuclear launchers. He's worked on nuclear rockets and aircraft nuclear propulsion and fusion rockets and RTGs and has always been a booster of the use of nuclear energy where it is appropriate.
~
None of the past nuclear rockets were really designed has
heavy lift boosters. Typical thrust levels for the smaller 1000 Megawatt systems would have been 75,000 pounds. The big ones such as Phoebus 2B would have provided roughly 250,000 pounds of thrust at a reactor power level of about 4400 Megawatts. All were designed for upper stage applications, NOT to be launched from planetary surface. The thrust of the Saturn 5 was 6,000,000pounds. In addition there are very much more difficult radiation shielding problems because of the presence of the atmosphere and ground to scatter radiation towards the crew. This, of course, is not a problem in the vaccuum of space. A typical large power reactor operates at 4000 megawatts.I have given a paper about radiation hormesis and am very impressed by the data. If we are going to Mars or to set up a base on the moon, nuclear upper stage makes sense.
~

This is in my opinion the most we can expect, and therefore the least we should ask for.
:D

If we are going to Mars or to set up a base on the moon, nuclear upper stage makes sense. Yeah, I agree with ya here... because the engine would be 'cold' at launch. I was just taking issue as using a nuclear engine as the initial stage.

Thanks for the info.

How far up would you need to put a nuclear upper stage before it would be safe to ignite? Can a chemical first/second stage put it this far up cheap enough to be cheaper than current systems?

Any height. Basically you are swapping a chemical final stage for a nuclear one. Whether it's a satellite, probe or rocket to mars you will get a lot more performance from nuclear power. That means less weight to carry. Which means less fuel in the chemical boosters. Which means more room for payload. So it gives you a lot more for the same kind of money.


"I was just taking issue as using a nuclear engine as the initial stage. "

Just because it has never been tried doesn't mean it can't be done. I have a feeling nuclear power can accomplish whatever we are innovative enough to ask of it. We've never built a nuclear launcher but thats not to say the idea hasn't been investigated.

Anthony Tate's Liberty Spacecraft for example. A true launch vehicle that makes chemical boosters look rather weak and pitiful.

Liberty Launch Vehicle. (http://www.nuclearspace.com/a_liberty_ship.htm)

http://www.nuclearspace.com/images/articles/mauk2b_small.jpg

I think an outline from page 10 onwards gives some basic details about the engines and how they perform.

This would produce radioactive waste... the same amount as the Chernoybl accident did. They are stating they can 'easily' seperate the radioactive gas and store it, but don't give any suggestion as to how. Assuming that this is far away from civilization it wouldn't kill the 40 people Chernoybl did, but would disperse this waste into the atmosphere.

I like the idea about releasing the waste gas once in space, I'm just not convinced the could collect it.

I think 26 people died as a result of Chernobyl. Employees of the plant. Poor souls. That was 16 years ago. Doesn't seem that long to me.

Beer is 13 times more radioactive than the cooling water discharged from a nuclear power plant. The exhaust from Liberty isn't any higher than for regular chemical boosters. There are concerns as far as engineering the vehicle. Each of the seven reactors is operating at 80,000 megawatts. The Phoebus 2B operated at 4000 MW. There is a high radiation level (neutrons and gamma rays)around the engines and there are no less than seven of them. Not an insurmountable problem. We just have to be aware that this is new territory. It's never been tried before. Bringing all of them up to power and temperature at once is not a simple task and the neutrons produced by each also effect the others. It will require extensive experimentation. I have no idea of the total inventory of Enriched uranium used. Sounds like a huge safety criticality problem but again probably do-able. Creating the electricity to heat the UF6 wont be easy. There is a huge radiation shielding problem especially when on or near the ground and in the atmosphere from air scattered radiation reaching the crew and secondary gamma rays produced in the air from neutrons leaving the system. Twice the diamaeter of a Saturn 5 means the frontal cross section is huge (4x) along with drag. The effects of radiation on components seems to be ignored. The cores will be radioactive for a long time which matters if the system would be used for landing. There is mention of high speed vacuum removal. Not entirely sure from whence cometh the power for that. Creating a vacuum is not easy either. For a first design concept it's not bad. Orion had far worse immediate problems and every one of them was solved on a shoestring budget.

I lost the first response; i'll try once more, I think I can risk my opinion :
nuclear spaceships should be build somewher up in space because;
1- The heavy dead payload to insulate radiation would cause a big problem if you have to do it from earth surface.
2- The possible radiation leaks or worse, would be minimazed in space.
3- The space ship should be accesed then by shuttle or from the orbital station where it should be build.
4- The engines shoould be mounted behind and outside the main body of the vessel, easely accessible for troublesooting porpouses.
5- It has to be managed by computers and robots.
6- It has to be ejectable if the necessity calls for it.
7- Man has not fiured out yet how to develop a nuclear engine capable of slow great accelerations to maintain hull integrity. There are many resources out there available to that porpouse and here on earth, that can repalace the fossil fuels. What can we say? Man hurry up!!!!! lets figure it out, time is so short in the life of fossil fuels.

Originally posted by Cthulhu
I think 26 people died as a result of Chernobyl. Employees of the plant. Poor souls. That was 16 years ago. Doesn't seem that long to me.
I got the 40 from the Liberty Launch Vehicle Report.

For a first design concept it's not bad. Orion had far worse immediate problems and every one of them was solved on a shoestring budget.
Agreed... one day they may be there, but for now I'd rather they test in orbit:) Although I wouldn't mind if it was they ground tested in the middle of nowhere.

It does sound promising if they can figure out a few design problems.

I don't know where Anthony got that figure for Chernobyl. He should stick to nuclear rocket engineering I think. The dumbass.

"for now I'd rather they test in orbit"

That would be nice if it was practical. The reason for designing a nuclear launcher is to increase lift capacity. If we could lob nuclear launcher engines into orbit just to test them then we really wouldn't need them. All nuclear mechanisms are tested before commercial utilisation. Power plants and naval engines had to be ground tested. I see you are still in awe of the radioactive bogeyman. That's ok. Nuclearphobia is still rife but we hope to fix that.

Open Pandora's Box, if you dare. (http://pub97.ezboard.com/fnuclearspacefrm28.showMessage?topicID=41.topic)


Wooooooooo!

Originally posted by Cthulhu
All nuclear mechanisms are tested before commercial utilisation. Yeah, I realize that... hence the "Although I wouldn't mind if it was they ground tested in the middle of nowhere. "

I always thought Australia would have been the best possible place to build early reactor plants. So much open space and desert. Experts agree it would be the safest country to have tried it. Instead it is the only developed nation without nuclear power plants to this day. Go figure. Far safer plants are now possible which would become harmless if you switch them off and failsafes ensuring this happens would be built in. Very clever but the energy commissions have said it would cost too much to replace the old Uranium plants. One just reached it's 60th Birthday.

There was good reason for early rocket tests being staged in the middle of Jackass Flats Desert, Nevada.

"It has to be managed by computers and robots."

That is something many designers have considered a better option than manned missions. Send robots instead. The time delay in transmissions is not all that important for lengthy missions. The public loved the Mars Rover. With nuclear power, robots might still take hours to perform complex tasks as the signals go back and forth between Earth and Mars but there is plenty of time. The Viking Robots operated for years whereas the Mars Rover's performance was measured in days. Without humans, you needn't worry about radioactivity. Neither solar, cosmic or engine radiation would have much impact on shielded electronics. It's very much do-able now and would pave the way for future manned missions. Best thing of all is it would be a lot cheaper. Life support for lengthy missions incur cost. Food mass is a lot greater than an electrical source which would be necessary anyway. Large reactor powered robots filled with high tech sensory equipment could walk or rumble across Mars this decade if we wanted them to.

Go here: http://www.islandone.org/APC/

Nice site and one I confess to never having seen previously. I'll post that up at NS.