I think Bill missed a crucial point, mentioned only briefly: We are talking about normal satellites staying in a "fixed" orbit without using any fuel - not a Buck Rogers type starship. Such an orbit is defined by the position and speed at a SINGLE moment. If the speed is correct, and perpendicular to the radius, it is a circle, and has a resulting period. If it is lower, the period and perigee (closest point) is smaller, unless the decrease is exactly at the perigee. If higher, the period and apogee is higher, unless the increase is exactly at apogee. If more than 1.414... times the circular speed, it will escape Earth gravity. If very low, what perceive as a "parabola of throw" (?) is the tip of a very narrow ellipse, with a perigee near the Earth's centre. To keep a 24h period closer to Earth, it would have to hover like a VTOL aircraft, farther away it would reverse the thrust to counteract the centrifugal force. So, the formulae that have appeared are ONLY valid for the standard geostationary orbit. Arthur C. Clarke did not invent this formula, or those that describe other "free-flight" orbits, they have been known since the days of Newton. But he was the first to realize how they could be used for communication satellites. ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Fri Oct 12 2001 - 14:38:32 EDT