"It's outside the environment."
> has considered a high-thrust nuclear
Of course we have. Always start at NTRS: https://ntrs.nasa.gov/citations/19690000736
> Certainly sci-fi has!
Our Solar system is a gravitational well that tends to put things in solar orbit. You really want the waste products to leave the solar system, which isn't terribly difficult, or you want them to land on the sun itself, which is exceptionally difficult.
Yes, it is counter intuitive but it takes less energy to leave the solar system get to the sun (you have to cancel out the Earth's orbital speed). Something learned from Kerbel Space Program.
In practice in the real solar system, the cheapest way to get from Earth to the Sun is to use Jupiter. Launch to there and reverse-slingshot to cancel out the orbital velocity and drop directly towards the Sun. The Parker Solar Probe would have done this, although decided not to because of the complications in designing to handle both the cold of Jupiter and the heat of the Sun.
PDF in this article is a 404
https://up-ship.com/blog/wp-content/uploads/2010/02/image25....
Let's not romanticize stupid ideas. Leave this one in the dustbin of history.
The trouble with nuclear rockets is that although you have plenty of energy, you still need to carry reaction mass - air, or water, or something - and a lot of it. That becomes the limit on delta-V.
(The great frustration of rockets: not only do rockets need something to push against, they have to carry it with them.)
"They push against their own exhaust" seems to be the idea that motivates the pushing explanation, but to me that just invites the question "using what?" and makes things even more complicated. At least in my opinion.
I think Newton's 3rd ([1], forces and reaction forces) is a better explanation.
[1]: https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion
(Emphasis added)
The rocket exhaust is "pushing against" the rocket itself, propelling it forward.
Rocket exhaust goes <- which creates the equal and opposite force -> which pushes against the mass of the rocket sending it on its way.
I think you meant "something to push with. But anyways, nuclear explosions make their own hot gasses out of the reactants, and the problem with that is getting that to be directed and also to not get the ship -you know- blown up in the process.
A better approach is to have a nuclear reactor to heat reaction gasses to much higher temps than chemical reactions allow for, thus increasing ISP a lot. The main problem with this is that nuclear reactors need a lot of cooling, even and especially after you shut them off, and the reaction gasses are going to be your only way to cool them. Alternatively you can carry huge radiators -- really huge, because in space you don't get to exchange heat with an atmosphere or a body of water, so you can only radiate or ablate away the excess heat, and either way would require huge amounts of extra mass. Another problem is that stop/start latency with nuclear reactors is huge, so they would only work for interstellar travel, I think. I'm sure if you carry enough reaction mass then nuclear reactors can work well for interstellar trips.
Aldebaran spacecraft proposed to "intake" air. But it's mass means it would have to intake A LOT of air. And that engine, as described in the article, doesn't seem to compress the air before each bomb expands it. I don't think it would work.
IIRC, the Orion project proposed to wrap each bomb in one ton of polypropylene. It would provide mass and also reduce radiation fallout.
We can probably can thank Fred Ordway (Marshall Spaceflight Center engineer) who Kubrick brought on board as technical consultant back then. (And of course for the look of the ships that are still so iconic over 50 years later I shouldn't leave off Harry Lange.)
But yeah, "crew module, long thing, engine" was how these were, virtually always, depicted in sci-fi.
https://en.wikipedia.org/wiki/List_of_stories_featuring_nucl...
> The biggest design above is the "super" Orion design; at 8 million tons, it could easily be a city. [...] This extreme design could be built with materials and techniques that could be obtained in 1958 or were anticipated to be available shortly after.
