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Old 08-18-2018, 07:45 PM
 
7,168 posts, read 3,920,595 times
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Quote:
Originally Posted by RocketDawg View Post
True. I remember hearing about NERVA early in my career, and a good aricle on it is in Wikipedia: https://en.wikipedia.org/wiki/NERVA As the article says, it lost political support (apparently the main senate sponsor died), and funding for space was tight in that era.

Unless I'm mistaken, NERVA was not intended for launching to Low Earth Orbit, but was meant as an upper stage engine to be used from LEO to its destination (moon or Mars). At the time, Saturn V would handle the earth to LEO portion, so you'd still have chemical rockets for the difficult portion of the flight. Saturn V first stage used kerosene/LOX and NERVA was LH2.
If my memory is correct the Saturn V-N (or C5-N) plans had a nuclear third stage to LEO. In any case I agree that the first stage would still have needed to be chemical.
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Old 08-18-2018, 07:50 PM
 
7,168 posts, read 3,920,595 times
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Originally Posted by davidt1 View Post
I hope this will remain a discussion and not a pissing contest. I actually am a believer in the Rare Earth Theory. That talk about alien propulsion tech was a jab at the UFO/Alien nutjobs. But since you brought it up, we are not in the Middle Ages. Once we built radio transmission towers and spacecrafts, we have advanced to the next level.

An alien race, no matter how advanced, still has to follow the laws of physics, gravity, aerodynamics, etc. Their tech won't look like magic to us. An alien aircraft would look familiar because there are only a few ways to deal with air friction in earth's atmosphere. A alien laser or ray handgun would still have to pointed a target and thus would look more or less like a gun.

Chemical fuel is around 20 times the weight of the space shuttle itself. Imagine carrying 20 times the weight of your car in fuel just to get around. That's a very poor ratio.
Wasn’t pissing at all, it’s a valid point I was making. In the Middle Ages science was at the level of Aristotle. Then Newtonian physics took over. Then General Relativity.

We may very well not know all that is knowable with respect to the laws of physics. Or we may but only in a 3-dimensional space. Or some other limitation.

From Max Planck in 1924:

“When I began my physical studies [in Munich in 1874] and sought advice from my venerable teacher Philipp von Jolly...he portrayed to me physics as a highly developed, almost fully matured science...Possibly in one or another nook there would perhaps be a dust particle or a small bubble to be examined and classified, but the system as a whole stood there fairly secured, and theoretical physics approached visibly that degree of perfection which, for example, geometry has had already for centuries.”

Either we have peaked or we haven’t. I have no way of knowing of course but I’d like to hope that new theories and practices are still to be discovered and put into usage.
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