Talk:Nuclear salt-water rocket

Citation for this article is "Entering Space", Robert Zubrin ISBN 1585420360 68.3.12.199 (talk) 21:38, 28 February 2008 (UTC)

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How would a engine using such a fuel work? -- angel'o'sphere

Within the propellant tanks, neutron density of the fuel would be low due to the geometry/neutron absorptive materials of the tank walls, so temperature would be low too and thus the fuel would remain liquid.. However when injected into the reaction chamber, the neutron density (and therefore temperature) of the fuel would rise sharply and therefore the water would more or less instantly change to high pressure steam which would exit through a nozzle at high velocity and thus propel the craft. Of course you then have radioactive steam floating about so you don't want to try this at home ! -- Derek Ross | Talk 16:36, Feb 9, 2005 (UTC)

Except that the radioactive steam should be travelling quickly enough that it's not bound by the Sun's gravity well, and should leave the Solar system in time. Just make sure you're not pointing towards Earth (or another inhabited body) when you fire that rocket... Wtrmute 14:34, 2 March 2006 (UTC)

Come on guys, this radioactive steam will have velocity of several tens of km/s (or else why bother with it at all? - go for chemical or ion engines then) and will most likely leave solar system. And even if it doesn't, it will be extremely diluted and not present any danger at all.

Even if engine is pointed to Earth, exhaust plume some divergence (let's say 5 degrees). Should be absolutely safe unless you are on LEO.

IOW: the only moderately unsafe way to fire this thing is to fire it in LEO with plume directed to Earth (which doesn't make much sense from orbital dynamics POV anyway).

Thats fine if you only launch one such vehicle, but if you started to extensively use them in Earth Orbit, even above LEO, you might get a cumalative effect, even with minor contamination from each individual ignition Spiz101 (talk) 01:40, 19 January 2009 (UTC)

Environmental damage

"such engines could not be used on the surface of a planet without terrible environmental damage occurring." Would it be worse than all the open air nuclear bomb tests? —Preceding unsigned comment added by 128.194.250.115 (talk) 16:15, 11 May 2009 (UTC)

Not necessarily. The largest volume of radioactive material from a nuclear bomb test is the fallout, the soil and water that are made radioactive and thrown high into the air. By contrast, this scheme would not necessarily eject very much radioactive material per period of time. It could probably be tested intially on Earth with just a few grams of material ejected. Further, since it would be an ionized gas, IIRC, it may be possible to capture some of it back magnetically. But even a test that directly emitted only a gram of radioactive material would draw protests, I'm sure. Perhaps it could be tested in some huge cavern. Testing it in LEO would be much less problematic, I'd think, because the gases would be dispersed before reaching lower altitudes. But such tests could wreak havoc on the Van Allen belts, not to mention nearby satellites or space stations. This is the first I've heard of nuclear salt-water rockets. It's a much more elegant concept than the Orion Project.   Will Beback  talk  10:17, 15 June 2009 (UTC)

These engines, like most nuclear reactors, don't scale down. You can't test at a few grams scale, because the engine won't run. Capturing the exhaust might be possible, but would definitely be difficult. Testing in orbit or on the moon would work well -- the exhaust is fast enough that it could easily be ejected out of Earth orbit by aiming it in the right direction. The vast majority of the radioactive exhaust would never hit the Earth or the atmosphere. I'm not certain what such a test would do to the van Allen belts if aimed such that the exhaust escaped orbit. Evand (talk) 16:10, 15 June 2009 (UTC)

It's hard to tell from the paper how much material would be needed to initate a reaction. I doubt it's more than a couple of kilograms. Even if all of that were released it'd still be far less radioactive material than even one of the above ground tests from the 1950s. And if the engine were pointed towards space then some of the gas may escape the atmosphere entirely. By comparison, one of the first hydrogen bomb tests left a crater "6,500 feet (2,000 m) in diameter and 250 feet (75 m) in depth", which created a mushroom cloud that reached a height of "130,000 feet (40 km) and 62 miles (100 km) in diameter". "[T]he cloud contaminated more than seven thousand miles of the surrounding Pacific Ocean..." A much smaller test displaced "12 million tons of earth "   Will Beback  talk  19:02, 15 June 2009 (UTC)