Makes me wonder if there ever will be a type of propulsion that doesn’t rely on throwing out mass behind a spaceship.
Project Orion
41–50 of 71 posts
Re: Project Orion
#42Earlier quoted context omitted.
I very much have a soft spot for Footfall. Sending up a battleship kludged into an Orion style ship to battle alien invaders is just so cool.
I haven't read that book in 30 years, but the description of experiencing the launch from inside the craft was so succinct and evocative I still think about it from time to time. "God was knocking and he wanted in bad ."
One of my favourite lines ever! Note, it wasn't from the perspective of inside the craft but rather the towns people huddled in a bunker in Bellingham.
Re: Project Orion
#43Makes me wonder if there ever will be a type of propulsion that doesn’t rely on throwing out mass behind a spaceship.
https://en.wikipedia.org/wiki/Solar_sail doesn't throw mass out the back. Although, it's not a lot of propulsion, it's something.
Re: Project Orion
#44Project Orion is a really bad idea. I guess it could be a good idea in specific situation where have to get a lot of mass off the planet and don't care about the effects. Problem one is that detonating a series of nuclear bombs in the atmosphere. The first couple are close to the ground and produce local fallout, the higher ones produce global fallout. Problem two is that detonating nuclear bombs in space causes EMP.…
Another problem with it is that, unlike an ordinary rocket engine, it cannot be tested on a test stand. The injection of nuclear units, as well as the interaction of the unit with the pusher plate, are intimately affected by the surrounding environment (all that hot gas from previous explosions in the atmosphere). Getting this thing to work reliably for launch from Earth would be a nightmare.
It might be easier to test the engine in space, say with an upside down unit on the Moon.
Re: Project Orion
#45Earlier quoted context omitted.
Interstellar nuclear-powered transport (1968) - https://news.ycombinator.com/item?id=28132756 - Aug 2021 (34 comments) There are a few more, under different titles. I remember reading Dyson’s autobiography a couple of years ago and he mentioned his involvement in the research. Absolutely amazing stuff.
I watched all 157 of these: https://www.youtube.com/playlist?list=PLVV0r6CmEsFzDA6mtmKQE... Really interesting. I spoke to him once at a book signing and asked him about Orion. In summary he said: would it have worked - probably, should it be done - probably not. Although he did make the point that pretty much every big engineering project kills people.
Also some good physicist gossip. Apparently Teller was a big sulk and Oppenheimer was a massive pain in the arse (some of the time, anyway).
Re: Project Orion
#46Makes me wonder if there ever will be a type of propulsion that doesn’t rely on throwing out mass behind a spaceship.
https://en.wikipedia.org/wiki/Solar_sail doesn't throw mass out the back. Although, it's not a lot of propulsion, it's something.
It still uses reaction mass; it’s just that it’s resupplied continuously by the Sun.
In some orbits around Earth and other planets with a string magnetic field, you can drive a ship by pushing on the planet. Also pretty low propulsion.
Re: Project Orion
#47Thermonuclear Orion could (on paper) reach 10% the speed of light. Proxima Centauri in about 50 years using technology contemporary with the Beatles and Woodstock.
This is why I have trouble dismissing the Fermi paradox. Either intelligent life that can engage in space flight is very rare (as in less than one per galaxy per billion years) or we are in a wildlife preserve or a zoo.
Re: Project Orion
#48Related: Interstellar nuclear-powered transport (1968) [pdf] - https://news.ycombinator.com/item?id=28132756 - Aug 2021 (34 comments) - thanks antondd! Orion Project [pdf] - https://news.ycombinator.com/item?id=22691219 - March 2020 (1 comment) Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf] - https://news.ycombinator.com/item?id=12705705 - Oct 2016 (99 comments) Project Orion (nuclear propulsion) - https://…
Interstellar nuclear-powered transport (1968) - https://news.ycombinator.com/item?id=28132756 - Aug 2021 (34 comments) There are a few more, under different titles. I remember reading Dyson’s autobiography a couple of years ago and he mentioned his involvement in the research. Absolutely amazing stuff.
Added. Thanks!
Re: Project Orion
#49There was a classic science fiction story with a twist on this idea; a low tech species was about to be discovered by a more advanced species. And according to the rules of the more advanced species, any planet that wasn't capable of space travel would become a client or vassal, and a planet with space travel would be seen as a peer. The protagonist built a pusher style rocket using an explosive, and launched the lig…
replying to all... The story you're thinking of is King Davids Spaceship by Jerry Pournelle. It IS a co-dominion story (so same universe as The Mote in Gods Eye w/Larry Niven) A few other uses of Orion in fiction that I am aware of: The Ship 'Michael' (as in avenging angel) from Footfall (Again by Niven and Pournelle). And the ship from Orion shall rise by Paul Anderson. A CBC Miniseries featuring a (faked) Orion der…
> A CBC Miniseries featuring a (faked) Orion derived interstellar ark supposedly launched in the 60's and the people that have been living on it for almost 40 years.
I think it was from SyFy. It was so bad it could only be SyFy.
Could be a good murder mystery, if it were not ruined by the whole fake ship idea.
Re: Project Orion
#50Earlier quoted context omitted.
https://en.wikipedia.org/wiki/Solar_sail doesn't throw mass out the back. Although, it's not a lot of propulsion, it's something.
It still uses reaction mass; it’s just that it’s resupplied continuously by the Sun. In some orbits around Earth and other planets with a string magnetic field, you can drive a ship by pushing on the planet. Also pretty low propulsion.
You can make it a couple times better by doing a close approach to the Sun. Within Mercury's orbit, you'll get 16 times (apologies for my napkin-quality math) the push it'd get around here.
And, with some mirrors, you can make a solar-thermal rocket as well.
All that makes me think: if today we decided to launch a Voyager-mass probe, what would be the maximum speed we could achieve with technologies we could deploy in a couple years (ruling out NTRs, liquid reactors, nuclear lightbulb or anything that requires a non-RTG fission reactor on board).
Imagining a chemical rocket for the initial push, then solar sail (maybe solar-thermal-rocket as well) from the perihelion until the distance to the Sun makes it worth to jettison the sail (maybe reorient the mirrors towards solar panels) and make the rest of the delta-v on ion engines powered by the solar panels increasingly replaced by a set of dedicated RTGs.