Monday, May 23, 2011

Nuclear powered spacecraft

This one may be so obviously speculative, there will be no need for a speculation alert.

The reason I posed this question yesterday was that, in the lower atmosphere, you have to take drag into account when you are traveling high speeds.  I figured as long as your thrust could exceed the weight of the craft (I'm guessing here), the spacecraft will rise.  On the initial part of your journey into space, forward speed would be relatively low.  If you are going 100 mph and straight up, after an hour, you would be out of the atmosphere.

If you had an energy source, and plenty of reaction mass, you could thrust straight up at a slow speed.  I was thinking, just use the atmosphere itself on the first part of the launch.  When the air gets thinner, it gets to be more of a challenge though.  At some point, it no longer makes sense.  At this point, use some reaction mass onboard and start going forward.  You want to go forward for what I propose next.  Once you are going fast enough forward, you can use the Earth's magnetic field for support.  You do this with an electrodynamic tether.   Drop the tether down, put electricity through it and it will push against the magnetic field giving lift.

How fast do you need to be going to get sufficient lift from the magnetic field to support the weight of the spacecraft?  Don't know about that one.  It may not be necessary to go orbital velocity- that's the point.  In fact, you may not have to go anywhere near that speed.

I may want to think about this a lot more.  The main thing here is that you can use what is available along with sufficient energy, you can get into space.  JP Aerospace is trying to do that with airships.  However, if enough energy was available, you may not even need an airship, nor would you need high speeds.  You could just use that energy to push against the earth's gravity using various techniques into order to achieve your goal of getting into space.

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