nuclear rockets

most know the general idea but here is a video in case you dont.



these programs are many decades old and were running at power levels of 1GW/1000MW, it would pump liquid hydrogen thru the core and the massively heated and expanded gas offered extreme specific impulse numbers 28 MINUTES at full power at and later over a HOUR!!!! at over 75K lbs of thrust.

i know NASA is looking at nuclear systems again but to me it seems crazy they didn't use these compact and powerful rockets. use chemical rockets to get the cores to space and than power them up and off you go. the reactors are amazingly compact and simple, they liquid hydrogen systems are many many times more complex.

we have launched tons(literally) of thermionic generators into space so the excuse of danger does not fly for me. It fuels the idea of secret space missions to the moon and mars, the video even talks about mission to mars.

i just find it amazing we have had this tech but never utilized it.

a reply to: penroc3

It is indeed something that brings many questions with it. But I would imagine that those craft and rovers that have and still use those systems got a pass based on size. But to use a larger one that can be used to propel a large craft may not pass whatever regulations that may be in place. I don't really know much about the red tape aspect of space travel. I only know some about the engines and other stuff in regards to that. But even then I am by far no expert.
Maybe Zaph, Anzha or Lookingatmars or some others can chime in with more details.

I always wondered if there wasn't some kind of "slow fission" nuclear rocket that might work without poisoning everybody. Rather than a firecracker, you get a bottle rocket, with the fission being slowed and aimed out the back (bottom).

Still the poisoning thing, though. People don't do well with radiation.

If the nuclear powered craft exploded would it not be like setting a nuke off? EMP, fallout etc.

Also, isnt a nuclear powered engine still too big and heavy to put in a launch vehicle?

a reply to: Allaroundyou

we have launched surprising amounts of radioisotopes and even one function reactor into space. Russia has a good handful of reactors in orbit.


even if there were regulations we could launch parts up to orbit and put it together in space, we already use remote manipulation in allllot of the nuclear industry so other than the fact its in space would be business as usual.

the obvious benefit to space travel is pretty obvious, even if it was scaled down for probes it would give humanity a pretty staging reach into our solar system and beyond.

after the rocket used all of the hydrogen it would have a potent power source, imagine a probe with 10 or even 100 of megawatts for its instruments and communications. with that much power we would be able to send telescopes and other observation equipment into deep space and have them run for a good while depending on the half lifes of the reactors isotopes.


Moohide: the reactor if damaged would just stop working, it might melt down but it would be in space so it would just be a hot ball of radioactive metal. a nuclear detonation requires extremely precise timing and other precise manufacturing and geometry to detonate.


there are at least 5 reactors in orbit as we speak that will take 1000's of years before we have to deal with them coming back down but even than no nuke, 'just' extreme contamination if left to it's own devices

a reply to: penroc3

I would say that a double hull vehicle where the void between inner and outer skin is filled with h2o, act as a moderator/shield for radiation (emissions and spacebourne) mitigation. a series of water filled compartments between bulkheads could satisfy both biological and electronic concerns. couple this with a plasma shield (wandering mind but watching a plasma torus in action.....) fore to aft and you're talking summit like. it may well be big but doable since my reasoning has stemmed from experience in the ship/sub construction industry.

a modularised system of construction could see these beasts lofted and assembled in orbit sequentially.

I recall a talk from years ago around the time of bayer fundfunk transmissions an astronaut describing how bare
steels in orbit had a tendency to bond.

perhaps jim will make a drive-by and either correct or enhance my simmering mind? that would be sweet.

regards f.

Radiation is a killer and shielding for it would be very expensive to put in orbit. It could be done, but probably isn't worth it.

They are talking about nuclear reactors again in space matched with ion drives for planetary exploration.

a reply to: fakedirt

a sub would make a great manned spacecraft.

radiation causing spallation from the walls would be a major concern for me. borated water or even borated rubber walls would help with radiation. the water could be filtered for what ever use but im not sure how much water would be needed to stop high energy particles.

you bring up another good point, using strong EM fields to help bend particles around and away from the ship, with a strong enough feild you could really mitigate some of radiation and with one or more reactors power would be plentiful. CT scans use very very strong magnets and in space if shielded the magnets would be around or at superconducting temps.

space travel seems very doable to me.

a reply to: penroc3

Russia has a good handful of reactors in orbit.

And one of them reentered over Canada 1978 . The debris field covered 15,000 square miles. That satellite only had 100 pound uranium on board.

Operation Morning Light

one nickel-sized piece of nuclear fuel they found could have killed its holder within hours

originally posted by: Grimpachi
Radiation is a killer and shielding for it would be very expensive to put in orbit. It could be done, but probably isn't worth it.

They are talking about nuclear reactors again in space matched with ion drives for planetary exploration.

I often wonder about a hidden space program. I see no reason to end the programs and that’s proven technically from the 60’s &70’s. The Snap10a was the first reactor in space progress. We must have followed up with something?
en.m.wikipedia.org...
The Nerva program that ended in 1972.
en.m.wikipedia.org...

The radiation problem in space is pretty overrated. Sure it is a problem for most spacecraft that were built for the sake of being low mass, however as soon as you start talking about anything of a reasonable scale, the issue of radiation decreases drastically. There was concepts looked into in the 60s ( en.wikipedia.org...(rocket) ) where a massive rocket allowed, counter intuitively, for savings due to the scale of construction and the lack of need for bespoke design.

Why do I bring that up? Because such a massive "low tech" rocket would have more than enough mass to shield a nuclear reactor. Sure I have not looked to deeply into nuclear reactors, however in my cursory lookyloo the amount of radiation is heavily dependent on the type of reactor. One of he major reasons why many reactors needed such massive amounts of radiation shielding is because they are (or can be used as) breeder reactors. They are used because they actively turn the fuel into other usable byproducts, and because of this they are more energetic, releasing far more radioactive energy. In civil nuclear reactors and most navy reactors it is usually a light-water reactor that gives off far less radiation, and is far less dangerous. Somewhat like the TRIGA reactors ( en.wikipedia.org... ) and require a relatively small amount of shielding (en.wikipedia.org... ) consisting of a pool of water 6-9 meters deep. This is an added bonus because the water could also be used as both an oxygen and hydrogen source, while also providing more than enough shielding to a crew.

This shielding would be provided due to the relatively low thrust, and long burn times required due to this, keeping the engine and fuel between the source of outside radiation and the crew ( from the sun ). Although this shielding would be insufficient for a portion of the return trip while the burn was taking place, but could again be turned around while drifting back towards earth.

Then there is the interesting part that the NERVA ( en.wikipedia.org... ) hasn't been developed further, and if modernized could be even more efficient.

a reply to: dubiousatworst

Somewhat like the TRIGA reactors ( en.wikipedia.org... ) and require a relatively small amount of shielding (en.wikipedia.org... ) consisting of a pool of water 6-9 meters deep.

All at the low low cost of $80,000 a gallon. For just putting water in low orbit.