Re: A good altitude for Ortillery? Math and astrophysics guys helpout

>In a message dated 11/30/99 4:30:08 PM Eastern Standard Time, 
>kaladorn@fox.nstn.ca writes:
>
>> Given:
>>  1) Geosynch is roughly 22,000 km (if I'm not way off base)
>>  2) Given geosynch is stationary wrt a point on the earth
>>  3) Given a lower orbit will be (of necessity) faster? I think
>>  4) Given the lower the orbit, the faster the orbit - so the further
>>  off geosynch, the less time you'll be able to see a given point on
the
>>  earth before going out of arc
>>  

One other point about geosynch that noone has mentioned so far - you can
only have a geosynch orbit over the equator, rotating in the same
direction
as the earth's rotation.  The whole point of geosynch is that the orbit
time of the satellite (ship/rock/lost spaceman/whatever) is the same as
the
rotational speed of the earth, so that the satellite APPEARS to remain
over
the same spot on the surface.  This can ONLY work for an equitorial
orbit....  So you'll have the effect of limited-time-over-target with
any
orbit other than equitorial ones...

And a geosynch orbit makes the satellite a real plum target - just
sitting
there...

Adrian Johnson
ajohnson@idirect.com