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by 93143
Wed Feb 25, 2015 9:15 am
Forum: News
Topic: NASA returning to NERVA?
Replies: 44
Views: 13862

Re: NASA returning to NERVA?

Isn't the decision between high thrust-to-weight and low ISP versus low thrust-to-weight and high ISP the normal design choice you have to make with any kind of rocket engine? For chemical rocket engines, generally that's taken care of with the choice of propellant combination. (The analogy with an...
by 93143
Sat Feb 21, 2015 1:28 am
Forum: News
Topic: NASA returning to NERVA?
Replies: 44
Views: 13862

Re: NASA returning to NERVA?

Also want to point out that subsequent projects to NERVA demonstrated much higher T/W than 1, high enough to SSTO. Wasn't this contingent on ISPs of 1600 or more? I don't know what you're referring to, but I do know that (a) solid-core NTRs can't do 1600 s, and (b) Dumbo was not subsequent to NERVA...
by 93143
Fri Feb 06, 2015 10:20 am
Forum: News
Topic: NASA returning to NERVA?
Replies: 44
Views: 13862

Re: NASA returning to NERVA?

Timberwind was a pebble bed design and had trouble with hot spots. Dumbo might be a better option for future development; same general idea but a structured core.
by 93143
Tue Jan 06, 2015 4:26 am
Forum: News
Topic: Angara News
Replies: 19
Views: 5898

Re: Angara News

Are you seriously equating manufacturing cost with reburbishment costs. Really? Of course not. Didn't you read my post? Let me try this again: Higher Isp gives a larger proportional performance advantage to a reusable than it does to an expendable, for the simple reason that the stage performance a...
by 93143
Wed Dec 31, 2014 8:44 pm
Forum: General
Topic: polywell mentioned in post
Replies: 1
Views: 715

Re: polywell mentioned in post

They claim EMC2 is targeting D-³He. I imagine the author saw "aneutronic" and jumped to conclusions without checking...

...either that or I've missed some major news...
by 93143
Sun Dec 28, 2014 2:56 am
Forum: News
Topic: Mach Effect progress
Replies: 2667
Views: 610639

Re: Mach Effect progress

A large part of my lack of concern is due to the fact that we don't yet have the technology in question, and by the time we do the theoretical ramifications will be much better understood. I actually disagree with the idea that M-E use accelerates the expansion of the universe. But my attitude is ba...
by 93143
Sat Dec 27, 2014 8:28 pm
Forum: News
Topic: Mach Effect progress
Replies: 2667
Views: 610639

Re: Mach Effect progress

Not sure what centripetal force masquerading like gravity gets you from the perspective as an energy source. Nothing. I'm referring to M-E gravity control like what GIThruster was talking about. If you can do that, you can almost certainly make an M-E energy generator quite easily. Also, in case yo...
by 93143
Sat Dec 27, 2014 2:25 am
Forum: News
Topic: Mach Effect progress
Replies: 2667
Views: 610639

Re: Mach Effect progress

[*] We have the ability to artificially create gravity, either by centripetal force or mastery of ME (assuming this is actually possible). [...] Another thing space at least the region around stars has a lot of is free energy. The only thing that is needed is either reflectors to concentrate the li...
by 93143
Fri Dec 26, 2014 9:03 pm
Forum: News
Topic: Angara News
Replies: 19
Views: 5898

Re: Angara News

If you can fly your first stages back, the Specific Impulse of their fuel becomes almost secondary. On the contrary. Hardware procurement is far from the only cost that scales with the size of the vehicle. And flyback and landing maneuvers increase the impulse requirement on the stage (or else load...
by 93143
Fri Dec 26, 2014 1:03 am
Forum: News
Topic: Angara News
Replies: 19
Views: 5898

Re: Angara News

If you want best possible ISP, staged combustion and high chamber pressure are favored. If you want low cost and rock solid reliability, gas generator or expander cycle and lower chamber pressure are preferred. It's an engineering trade off. I am curious to see how the Raptor will perform in this r...
by 93143
Thu Dec 25, 2014 9:26 am
Forum: News
Topic: Angara News
Replies: 19
Views: 5898

Re: Angara News

". . .powered by RD-191, arguably the world’s best “clean” engine that uses kerosene and oxygen as fuel." Does it produce higher Isp's and have lower weight and higher reliability than the SpaceX thrusters like the Merlin? Vacuum thrust-to-weight seems to be just shy of 100, versus ~150-1...
by 93143
Wed Dec 24, 2014 9:37 pm
Forum: News
Topic: Mach Effect progress
Replies: 2667
Views: 610639

Re: Mach Effect progress

The things you listed are not real road blocks It sounds like you may have misread my post. I don't recall listing any "road blocks"... More importantly, you were complaining about gravity wells in general, not Earth specifically. And my basic point was that high-thrust METs obviate the b...
by 93143
Wed Dec 24, 2014 7:59 pm
Forum: News
Topic: Mach Effect progress
Replies: 2667
Views: 610639

Re: Mach Effect progress

why would you do construction in a gravity well. I get that it will be necessary in the short term. But it seems to me it would be much easier overall to eventually migrate all manufacturing into space. Why? Gravity, air and easy access to resources make most things easier, not harder. Barring spec...
by 93143
Fri Dec 19, 2014 11:03 am
Forum: News
Topic: Mach Effect progress
Replies: 2667
Views: 610639

Re: Mach Effect progress

I'm wandering what the advantage of propellant free drive over traditional Newtonian rocketry... a single proton can be accelerated asymptotically close to speed of light as soon as energy supply provides sufficient energy... besides, a single relativistic proton may have mass of rocket once it clo...
by 93143
Thu Oct 30, 2014 12:52 am
Forum: News
Topic: Orbital Sciences rocket explodes on launch
Replies: 49
Views: 11802

Re: Orbital Sciences rocket explodes on launch

I've seen "rapid unscheduled disassembly", which on the NSF forum is often abbreviated RUD. Whatever you call it, combined with the earlier test stand failure, this is kinda worrying. But of course the thing to do in these cases is hold off making any hasty judgments until the accident inv...

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