Very basic question: How do they stay in orbit?
Very basic question: How do they stay in orbit?
(OP)
Sorry for such a basic question but I never really thought about waht keeps a satelite at a constant height. You've got gravity trying to pull it towards the earth and centrifigal force trying to push it away from earth. It seems like that is very unstable - a little deviation either way would send it plummeting towards earth or into space. So, how do they stay in orbit?





RE: Very basic question: How do they stay in orbit?
TTFN
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RE: Very basic question: How do they stay in orbit?
Disturb an orbiting body slightly, and it remains in orbit, but maybe in a slightly different orbit, or maybe one that’s more elliptical than circular.
PBS Nova done several good programs on this.
RE: Very basic question: How do they stay in orbit?
As for why it otherwise stays in the same orbit, it's conservation of energy. If the PE doesn't change, it can't physically have moved in altitude, so it's at a constant circular orbit. An elliptical orbit is slightly more complex, but again, conservation of energy puts it at the altitudes on a repeat orbit.
Slingshot orbits are a little bit more complicated than that, since they actually involve an energy transfer between the two bodies involved.
TTFN
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RE: Very basic question: How do they stay in orbit?
Eric R
http://www.icpdas-usa.com
RE: Very basic question: How do they stay in orbit?
RE: Very basic question: How do they stay in orbit?
Gm = V^2*r
RE: Very basic question: How do they stay in orbit?
If you really want something to ponder, check out the Clohessy-Wiltshire equations (or Hill equations). These are by far the most interesting thing in the subject of orbital mechanics. These eqautions govern the motion of orbiting bodies and are quite non-trivial. For instance, if you were in orbit and wanted to dock with another spacecraft at the same altitude, would you speed up in the spacecrafts direction? Keep in mind that if you speed up you will ultimately put yourself in a higher orbit, and thus a slower period. Also, what if you were on the shuttle and someone on the opposite end of the ship wanted you to throw them a hammer? Would you throw it towards them or away from them? Check out the Hill equations and I'm sure you'll fall in love with the counterintuitive principles you will learn.
RE: Very basic question: How do they stay in orbit?
RE: Very basic question: How do they stay in orbit?
RE: Very basic question: How do they stay in orbit?
See Thread 25-137712
In fact I'm not so sure it will ever happen...
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