Re: Project Orion Reborn.


Posted by Pasti on Feb 11, 2004 at 23:17
(67.69.240.236)

Re: Project Orion Reborn. (Wayne Smith)

P:"Look, I worked in plasma physics for three years in my "youth", both on cold plasmas(including ablation and chemical plasmas), and on hot plasmas - confined tokamak type, not nuclear."

W.S.:Not nuclear. Right.

Neither did they, don't forget about this.And I am under the impression that neither did you.
Whatever they did in terms of nuclear effects was rather sporadic and based on not so many nuclear tests.You can call this research, I call it the beginning of reasearch.It is a long way from there to solid and tested conclusions.

W.S.:Yes, yes, so you keep saying. We all know you could have done a much better job. A pity you weren't available.

Sarcasm aside, you have to admit that the cannon is the most logical means to prove the principle.Which makes you think about certain competency issue of the PI's in the project...

P:"Suffices to say that for the dynamite propelled thing they really didn't need theorists."

W.S.:Correct and the theorists didn't have much involvement with it. The engineers worked hard to complete it before the experimentalists could get involved.

Exactly what I was saying. But they involved theorists nevertheless (Dyson being the obvious example) in futile calculations and designs at that point,without knowing if the project will actually survive.This is bad management, to say the least.

"The model wasn't originally part of the program. It was a last minute addition just to impress the twits in charge of funding."

You mean it was not in the proposal they submitted,but it was in the revised proposal when the grant was approved?This is not quite last minute, you know.Not in term of the research they started AFTER the grant was approved.

"Several calls were made to request material tests during nuclear weapons tests. The first I think was 3 large steel spheres suspended in the air 3 metres from the centre of a nuclear blast. They were later found perfectly intact but for a few millimetres of ablation."

A few milimeters of what you call ablation (I would call it simply vaporization) is an enormous amount of vaporized material. Let's make a rough estimate.Say at 3 meters you have 3 mm of vaporized material.At 60 m, which I think is the proposed detonation distance from the pusher plate, that would roughly mean 3 mm x9/3600=3mm/400.Now, for a large Orion ship, with fission they estimated ~10,000 explosions to put it in orbit I think. This means that the thikness of evaporated material is (3mm/400)x10,000=75 mm.This is a lot of material to loose.And fatigue due to the explosion,chemical change, internal stress build-up? And the exposure to the hot plasma is long enough to produce significant induced radioactivity (although Fe would decay rapidly,other components may not, like C isotopes).

"Wow, I didn't realise you had intimate knowledge of the classified work done. All I have is the declassified material."

You don't need to have classified material to understand certain aspects of the project and estimate the problem that arise.Especially if you also did design in your projects, and are familiar with physics and a little engineering.See above.
Don't forget, there was no fundamental breaktrough in their research,not nowdays and not then,so the "classified" status was related more to the word nuclear than to the results of their research.

"It is the only option for manned space travel. That in itself is sufficient reason to revive it."

Definitely it's not.On the scale you are talking about, solid fuel engines, or even jet engines become feasible and much more efficient (less power loss, more maneuvrabbility, retro jets, etc).

"People like you once said the same thing about a round earth."

Should I assume that people like you are responsible for teh waste of money at NASA and for the lives lost in the process?

"Orion is perfectly reasonable, the technology is feasible and those familiar with the concept believed it was the only common sense solution."

Common sense?Whose?

"Huh?What benefits?What can one launch of one big ship do?"

It can carry the industrial infrastructure necessary to maintain a permanent foothold in space. Everything necessary to mine, refine and utilise space resources.

"You forget these things have to be refueled."

I haven't forgotten anything. Uranium isn't restricted to the earth.

"I gave you arguments, but you have ignored them.Your choice."

I haven't ignored your concerns. Atleast not intentionally. Please point out which arguments have gone unanswered. I may have passed over a few comments that seemed obvious.

"We have "conquered" it 30 years ago,and to what avail?"

We didn't conquer anything. How many was it? Six short visits to our satellite. That isn't conquering space. Apollo wasted a million dollars a day. It was the worst thing that ever happened to space exploration. Was probably a major influential cause of the following recession. Every spare dollar was redirected from other programs including Orion. It murdered the space age.

"With the actual technology one could build a much better and faster ship than the Orion, and actually do travel into space."

That has been the mantra for the last 30 odd years. NASA's would love to hear you say that. Their philosophy is to just keep throwing money at their stupid programs until the damn things work. For the cost of the ISS we could have colonised the entire solar system several times over. We don't have any other technology and guess what. There isn't going to be any.



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