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Now I know this suggestion is entirely impractical, however I'm curious as to how much lift could be acheived through a buoyant object emerging from water.
200 mph isn't very fast, using the rocket equation, I calculate that it would make less 3% difference to the size of the rocket you need to build to reach orbit.
Most efficient of all is if you don't have to carry the fuel/energy source with you, otherwise most of the fuel goes into lifting other fuel...
Quote from: wolfekeeper on 19/09/2012 23:55:32200 mph isn't very fast, using the rocket equation, I calculate that it would make less 3% difference to the size of the rocket you need to build to reach orbit.A 3% savings would be HUGE.Consider the ...sorry, you cannot view external links. To see them, please
REGISTER or LOGIN.Mass: 249,500-733,400 kg (550,000-1,616,800 lb)Payload to LEO 8,600-22,560 kg (18,900-49,740 lb)Payload to GTO 3,900-12,980 kg (8,500-28,620 lb)A 3% savings would be essentially equivalent to about 100% of its payload.
Railguns are very subject to rail erosion with each use, and are unlikely to be much use for space launch.
Given no friction and say 2 miles of tube, does anyone know how fast it is possible to theoretically accelerate a one ton object? Lets say your using magnets as the "accelerant"?
you have to get to about 400 miles if you want to stay in orbit - even a low one),
Quote from: Airthumbs on 22/09/2012 05:45:46Given no friction and say 2 miles of tube, does anyone know how fast it is possible to theoretically accelerate a one ton object? Lets say your using magnets as the "accelerant"?Supermagnets and magnetically soft iron can achieve an acceleration of 1000g
A pure gravity U shaped track would essentially give no significant benefit over a static launch.
The same would be true if you bored a hole through the center of the moon for some kind of a magnetic accelerator. One would spend more time travelling towards the center of moon than away from the center of the moon. And, thus would get an extra boost from the moon's gravity, albeit weak.
This time effect of gravity may also explain why there is a benefit of a nearly vertical launch of a wingless rocket vs launching at an angle, say 45 degrees. One wants a launch that gets to as high of an altitude as possible, as quickly as possible.