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Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

ntrs.nasa.gov

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Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#71

Post by mikeash »

api wrote: post #60
andygates wrote: post #33

Earlier quoted context omitted.

> nuclear is unfashionable at the moment It's more than that - this isn't just hippies, it's every major power on the planet. To fly Orion you have to put hundreds of nuclear explosives in orbit and pinky-swear that you're not going to use them to obliterate your enemies. Nobody is going to accept that. Orion's a fun paper rocket but will never be more. Engineers and they "yay nukes!" crowd will drag it out every cou…

Even worse: the EMP from an Orion launch would fry a lot of satellites. It's not a practical design for use anywhere near... anything. You could launch one from the far side of the Moon, but if you have that kind of space presence there are better engine designs. Some have been posted elsewhere in this thread.

Yes, Orion looked a lot more attractive back before civilization became reliant on huge quantities of sensitive electronics in near-Earth space.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#72

Post by Symmetry »

maverick_iceman wrote: post #65
Symmetry wrote: post #50

I think I like the recent work on pulsed fission-fusion better. Basically you have a normal z-pinch fusion system but surround the fusing hydrogen with U238. It absorbs the fast neutrons from the fusion, fissions, and creates more heat driving the fusion. There's some radioactive waste flying out the nozzle but if you're already in space that's not a huge problem. On the upside, people aren't going to get nervous abo…

What's the Isp of this method?

The first paper mentions 19,400 seconds at one point; versus 450 for hydrolox and 3100 for Dawn's ion drive. I did a blog posts on the theoretical limit on this sort of drive a while ago, using propellant velocity instead of ISP.

http://hopefullyintersting.blogspot.com/2015/04/rockets-vi-v...

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#73

Post by mikeash »

wyager wrote: post #26
moseandre wrote: post #10

Please read Freeman Dysons's "Disturbing The Universe". This book is autobiographical and Dyson explains his arc of passion for nuclear propulsion and Orion. His strongest statement in this book is some deep respect for a biological scientist who, after seeing declassified army training manuals on chemical and biological warfare, supposedly discouraged the entire western hemisphere from further develomepment. This ki…

>This kind of nuclear research is, thankfully, over. Nuclear pulse propulsion is the only currently viable technology that could be used to make humans an interstellar species. It would also allow us to practically ship up enough materials to build self-sustaining habitats in near space. It is extremely unfortunate that this kind of research is over. Fun fact: the background radiation levels introduced by nuclear pro…

Radiation hormesis models aren't "more accurate." The long-term effects of small amounts of radiation are simply not well understood. It could be good, it could be bad, it could be neutral.

The far bigger problem for launching Orion from Earth is the electromagnetic pulse frying every satellite above the horizon and a bunch of stuff on the ground.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#74

Post by Symmetry »

Tuna-Fish wrote: post #59
luckystarr wrote: post #41

Nuclear salt-water rockets! https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket Powerful, fast, intriguing and disgusting. :)

Project orion has the name recognition, but nuclear salt water rockets would just be a much better use of the same amount of fissiles. Maybe we should start reposting the wikipedia link every month until people remember mr. Zubrin's creations more than project Orion?

It's hard to say which is a more efficient use of fissiles. It's easier to burn up all your fuels in the context of an explosion as in Orion than in a saltwater rocket. On the other hand by bulking out the fuel with water to form a larger mass of propellant the saltwater uses it's energy more efficiently at the cost of lower ISP.

But really, if we're willing to leak radioactive byproducts I think an open cycle gas core might be the best bet in terms of not-yet-developed rockets.

http://www.projectrho.com/public_html/rocket/enginelist.php#...

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#75

Post by maverick_iceman »

moseandre wrote: post #20
jharohit wrote: post #17

Earlier quoted context omitted.

I would rather classify that as "unfortunate". Yes there are obviously biological harms in radiation exposure but that is what science & engineering is for. We know the power of nuclear energy so in order to harvest it, the right thinking should have been like "How can we safely extract it so that it does harm people in the mix?" rather than "Oh its harmful to humans so obviously we should give up and not use it". Cu…

I'm not sure all of the opposition to nuclear research is about dangerous byproducts from the typical situation(s). It is about the improbable problematic situation which lead to exponential disaster that are scary, and, even if improbable, inevitable...

Yay, chicken little!

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#76

Post by maverick_iceman »

simonh wrote: post #43
wyager wrote: post #26

Earlier quoted context omitted.

>This kind of nuclear research is, thankfully, over. Nuclear pulse propulsion is the only currently viable technology that could be used to make humans an interstellar species. It would also allow us to practically ship up enough materials to build self-sustaining habitats in near space. It is extremely unfortunate that this kind of research is over. Fun fact: the background radiation levels introduced by nuclear pro…

On the other hand if we'd gone all-in on nuclear pulse launchers, there would have been no incentive for companies like SpaceX and Blue Origin to develop reusable conventional rockets which will hopefully achieve the same result at lower environmental and perhaps also financial cost.

How can chemical rockets with ~3km/s exhaust velocity ever achieve the same result? Also if we had gone all in on this concept maybe today SpaceX and BO would be working with a much more promising technology.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#77

Post by elsonrodriguez »

IndianAstronaut wrote: post #29
jharohit wrote: post #15

Earlier quoted context omitted.

Exactly - i think there should be more companies & organizations working towards pushing this. To become space-faring, we need to get from 1ev per bond of molecule level of energies obtained from chemical to 1GeV levels atleast!

We are a long ways from becoming space faring. For the cost of sending one human to Mars, we could send ten rovers to Mars.

For the cost of sending one human to Hawaii, we can set up 10 weather stations instead.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#78

Post by elsonrodriguez »

grkvlt wrote: post #52
XorNot wrote: post #45

Earlier quoted context omitted.

Not if Elon Musk gets his way. If the cost profile works out, sending a human will be cheaper then sending a robot.

Even then, we can still send rovers more cost effectively than people! You can throw away the life support mechanisms, and so on, and get 550 tons of pure mars rover in your interplanetary transport. At ~800kg for a curiosity-level rover that gives about 600 rovers, instead of 100 people. What to do with your 600 curiosity rovers on Mars is left as an exercise...

The Curiosity rover has driven 9 miles in a little over four years on Mars.

The Lunar Rover that came with Apollo 17 drove 22 miles in a little over 4 HOURS.

As it turns out, humans are the best robots.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#79

Post by binarytransform »

maverick_iceman wrote: post #68
andygates wrote: post #33

Earlier quoted context omitted.

> nuclear is unfashionable at the moment It's more than that - this isn't just hippies, it's every major power on the planet. To fly Orion you have to put hundreds of nuclear explosives in orbit and pinky-swear that you're not going to use them to obliterate your enemies. Nobody is going to accept that. Orion's a fun paper rocket but will never be more. Engineers and they "yay nukes!" crowd will drag it out every cou…

Anything that can accelerate a starship to a velocity of ~0.1c can have devastating consequences if pointed to earth. Just like planes can be used to destroy skyscrapers. Chicken littles notwithstanding, having a much faster mode of transport is worth the risk.

It may be worth the risk but that doesn't change the fact that what you refer to as "Chicken Littles" represent power players in an intractable political dynamic. The only way this kind of cooperation happens is when humans move past current notions of nation states and begin to think strategically as a species.

Re: Nuclear Pulse Propulsion – Orion and Beyond (2000) [pdf]

#80

Post by Pinckney »

masklinn wrote: post #69
maxerickson wrote: post #64

Earlier quoted context omitted.

I'm talking about just flying the entire Orion ship to Earth, loaded with propellant bombs. Sure, you can try to take it out during the journey, but that may be complicated by it being the highest g ship in existence for the Mars-Earth distance. Once/if it arrives, you have the same strategic problems you have if you build it in orbit.

> I'm talking about just flying the entire Orion ship to Earth, loaded with propellant bombs. Er… yes? > Sure, you can try to take it out during the journey, but that may be complicated by it being the highest g ship in existence for the Mars-Earth distance. That's not really a complication, it's still taking months to make the trip, and while it might be "the highest g ship in existence" that's linear acceleration,…

Since Orion doesn't need to accelerate constantly, it's in principle quite possible to turn it and fire bombs in the direction of any interceptor, and the thick pusher plate makes it actually pretty durable from some aspects. What happens when two Orion ships duel, I don't know, but shooting it down isn't quite as simple as for most other spacecraft.
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