Project Orion. Worthy of a second look? - New Article at Spacedaily.

RobertDyck · 2003-03-22 10:15:02

Fission bombs go off when the pieces of fissile material (uranium or plutonium) are brought close together. If you bring them together slowly it will fizzle, if you do it quickly they will explode. That is why a chemical explosive is used to move the pieces together quickly. Then the question is what will cause the chemical explosive to go off? That depends on the chemical explosive, but something must permit the explosion to propagate throughout the material. Modern chemical explosives can withstand a lot of shock or heat without detonating, but there is a limit.

On the positive side, if the chemical explosive is triggered by the shock of a nuclear explosion, chances are the explosive on one side of the bomb will go off first, and the explosion will propagate slowly around the nuclear pit so that the pieces of fissile material are not evenly crushed together. An uneven detonation of the chemical explosive would probably cause a nuclear fizzle, not a nuclear explosion.

Dingo1 · 2003-03-23 22:22:35

The problem is with the triggering devices used to detonant the chemical explosives, forcing the sections of uranium or plutonium together at high speed. They are called Krytons.

From test made in the 50's and 60's Krytons though very hardened against radiation, can be effected by a nearby EMP, causing premature detonation.

It is why nuclear devices are as heavy as they are, is to protect the krytons from EMPs, as well as shielding from radiation exposure to personnel handling the devices. The amount of fissionable material itself is not that much, depending on the size of the detonation wanted.

A question, how will the heat generated by the multiple explosions going to effect the pusher-plate, and prevent it from being vaporized???

Next question, what is the G-force that is going to be generated???

Dingo1 · 2003-03-24 13:31:27

Still, how many G's of force are going to be present?? A nuclear detonation generates tons of force, that is instantly going to be applied to the pusher plate and the ship, and the crew

Gennaro · 2003-03-25 21:55:07

A layman's point of view:

I've known about project Orion since I was about 15 and read Carl Sagan's Cosmos. Having come to view the entire concept as ridiculuos (never even contemplated it for Earth launches because of radiation issues), I must admit that reading through the four pages of this thread has caused a change of heart.

Well done Mr Nuclear Space!

I mean, just think about the thrust to weight ratio obviously related to this technology! (Okay I might still need to look into some details on my own here.) Yet with the productivity implied, does it really matter if one or two viechles might explode at some desolate location, especially considering the great number of even thermo nuclear rocket viechles needed for the same amount of payload? (If those are feasible for down gravity well launches that is, at least I had hitherto thought so!)
Astronauts and related staff are asked to have the right stuff. It's their duty to put their lives on the line and not to wheen too much about security. Test pilots and speed freaks for Christ's sake. Moreover, as soon as we get some decent infrastructure up there, maybe we won't need to continue any potentially hazardous earth launches, anyway.

Plus, Werner von Braun got sold on the idea. Then it simply have to be good!

And this is the second time tonight I heard the name Freeman Dyson (obviously the project manager in the old days). Sounds like a good omen.

Shaun Barrett · 2003-03-26 02:11:12

I like your independence of thought, Gennaro!
It seems you and I are in agreement about this. More research would certainly appear to be warranted. And I haven't seen NuclearSpace say anything unreasonable about this so far. All he wants is a fair hearing for the concept - and is prepared to scrap it as and when the evidence shows it to be non-viable from an environmental viewpoint.
I can't see a problem with this attitude. It's called science!!

Dingo1 · 2003-03-27 12:10:17

Can the same principle be used with non-nuclear chemical explosives. There have been massive upgrading in military and civilian explosives that approach the range of small yield nuclear devices. I ask this because of eviromental concerns raised with the use of nuclear devices, as well as the huge uproar from the world population with the thought of nuclear devices.

I also have major concerns in regards with site safety. Because of the number of nuclear devices needed to launch it, it would possibly be a major target by extreamist and radicals who might try and get their hands on the devices for use outside of peaceful ourposes.

I do understand it's potentual, exspecially for interstellar exploration, as a second stage booster (chemical being first stage to get it into space) towards bringing a craft up to Barnerd Ramjet speed

soph · 2003-03-27 14:43:20

Why use chemical? As I've said a few times, a GCNR would be a much better way to have a single stage, clean, efficient booster, with many functions, no minimum mass, and huge payloads. You don't need 25% of a 4,000 tonne craft devoted to a pusher plate.

soph · 2003-03-28 05:23:58

Orion...hammered out? No, it was killed decades ago. We may have numbers, but NTRs have actually been built, which means Orion has a backseat in terms of experience.

We are further along towards building a GCNR--we know we can build NTRs, Orion is purely theoretical.

soph · 2003-03-29 06:10:22

A single GCNR engine would prove a very effective engine for an Earth based SSTO and spaceplane. Low fuel, fast travel, clean. Launch and land on an airstrip for convenient replacement of current airplane commerce.

Pulse has not been proven. I have not seen any reports of a pulse rocket built. NERVA was built and tested.

And 250,000 lbs. of thrust on a 1960s engine doesn't suck. Using modern technology and designs, we could vastly improve that. Orion hasn't even had a test in a lab with nuclear explosives on a pusher plate. There is no guarantee we could "build it tomorrow." And there is that little issue of international treaties, which don't apply to NTRs.

Dingo1 · 2003-03-31 12:51:29

I understand, but here are a few points that will have to be overcome first.

1. Radioactive waste. We have yet to be able to create a device that does not generate radioactive waste. Also the first few bursts are going to be at ground level, generating tons more radioactive waste that will have to be stored.

2. It is against International Law (as it currently stands) to use nuclear devices in the atmosphere, as well as in space.

3. It would be polical suicide for any polition that would vote for it. The "No Nukes in Space" is a powerful organization covering every continent.

4. Very expensive. We are talking about several billion dollars.

5. It would be under the control of the military. Due to the nature of the "fuel". Only 2 governments have the nessisary "fuel" available. The US and Russia. Neither country would turn over weapons grade uranium and plutonium to a civilian organization, which would massively drive up the price tag

6. Public opinion. The general public is scared to death about radiation, even the safe use of it.

tim_perdue · 2003-04-16 20:03:16

I enjoy the nuclearspace website - I wish more articles were put up there.

As for Orion, it's pointless. Even if it were practical, it will never be acceptable. NTR is a different story - far-fetched in terms of it being launched from earth to LEO, but not impossible as Orion is.

Ad Astra · 2003-04-16 23:05:52

Orion was feasible two generations ago and nothing has changed. If anything its more feasible in light of new technology. We could build one tomorrow morning if we wanted to.

After reading George Dyson's "Project Orion," I get the impression that the Orion group was still rather far away from getting definitive answers to their engineering problems. The most distressful was finding a method to compensate for a dud bomb. Others included the system to eject the bombs behind (through?) the plate and the shock absorber system.

That's not to say I think Orion is impossible; in fact, I think that it is our best bet for exploring the outer planets once enough time and money are invested in development. Thankfully, Andrews Space & Technology is doing research into magnetic pulse rockets that are quite similar, in design philosophy, to Orion.

Gennaro · 2003-04-17 03:07:40

Others included the system to eject the bombs behind (through?) the plate and the shock absorber system.

- Yeah, I know this might risk sounding stupid to people with skills at engineering, but I couldn't help thinking about that as well. In depictions of the Orion there's a 'hole' in the pusherplate through which the bomblets obviously are released. But will a blast and radiation protective pusherplate really remain just that with an opening through it? How will the ejection system cope with the repeated stress of 1 megaton nuclear blasts?

A second thing, which is a little unclear to me. Dropping a-bombs behind the ship when it's accelerating through space sounds allright, but what about the initial blast from the surface? Will the ship be put high up in the air on a sort of gigantic scaffold (tenacity?) or will there perhaps be a giant dug out below it, will the first bomb be placed outside it rather than dropped from the ship or what?
I'm primarily thinking about the big original, 160 man version - something of the size that can carry all what is needed to Mars to go there "in style", like heavy radiation plating, big life support artificial g generating cylinder etc.

Maybe this has been dealt with in previous threads, but in either case I'm afraid to say I must have missed it.

Informed opinions from people like soph or Nuclear Space and anyone else requested.

soph · 2003-04-17 08:21:20

But will a blast and radiation protective pusherplate really remain just that with an opening through it? How will the ejection system cope with the repeated stress of 1 megaton nuclear blasts?

Depends on who you ask. Some people say the thing would have to be a kilometer thick to protect the ship, others say that the steel would hold up. This is something that really has to be tested thoroughly beforehand, but who is going to put thousands of .1 kt atomic bombs in a confined space with a steel plate, and fire them off, to make sure that it will work?

I'm primarily thinking about the big original, 160 man version - something of the size that can carry all what is needed to Mars to go there "in style", like heavy radiation plating, big life support artificial g generating cylinder etc.

In my opinion, anything larger than 10 people for the initial missions is wasteful. The first missions need only to establish an infrastructure capable of supporting people, and lay the groundwork for future science and manned missions. If you keep the initial missions small, you can set up this infrastructure more cheaply, and quickly (the base doesn't have to support 160 people and expand at the same time).

I think we should also send cargo to Mars on an annual basis (for example, more domes, agricultural supplies, etc.) that the mission personnel can use to set up a full base.

Orion was designed to be launched from orbit. It would have been assembled in orbit, it's parts carried up by 8 Saturn V launches ($4 billion dollars!). The plans were not for Earth launch.

Phobos · 2003-04-21 20:34:17

Quote
3. It would be polical suicide for any polition that would vote for it. The "No Nukes in Space" is a powerful organization covering every continent.

No Nukes in Space is a noisy minority group with no solid support base. Even greenpeace doesn't take it seriously. They have no serious power to influence government decision making and this was demonstrated during the launch of Cassini. Fearmongers like them are a joke. Politicians generally support poll results and the public response so far has been great.

The "No Nukes in Space" people have been moderately successful if you consider that ESA doesn't condone the use of nuclear power in space, but the anti-nuke activists have been very unsuccessful in the United States. Just look at Project Prometheus and the various spacecraft which have used plutonium power sources despite the court battles and haranguing of groups like Greenpeace and the Global Alliance against Nuclear Power in Space. I'm holding out to see how well the mini-orion engine does. The full fledged nuke pulse ship might not have a political chance in hell of becoming reality but its little sister might.

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#51 2003-03-22 10:15:02

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#52 2003-03-23 22:22:35

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#53 2003-03-24 13:31:27

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#54 2003-03-25 21:55:07

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#55 2003-03-26 02:11:12

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#56 2003-03-27 12:10:17

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#57 2003-03-27 14:43:20

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#58 2003-03-28 05:23:58

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#59 2003-03-29 06:10:22

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#60 2003-03-31 12:51:29

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#61 2003-04-16 20:03:16

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#62 2003-04-16 23:05:52

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#63 2003-04-17 03:07:40

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#64 2003-04-17 08:21:20

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

#65 2003-04-21 20:34:17

Re: Project Orion. Worthy of a second look? - New Article at Spacedaily.

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