On Jan 28, 12:48*pm, Dr J R Stockton wrote:
In sci.space.policy message
.au, Sun, 27 Jan 2008 11:53:50, Sylvia Else
posted:



Anyone know what kind of orbit a spy satellite would be in? Would they
always be polar, or might Sydney be safe?

If you mean the Sydney in Australia (Vanuatu, South Africa, and Canada
also have at least one each, and the USA has at least two), then it is
at about 34 degrees South. *A good proportion of the places worth spying
on, like most of the USA, are further from the Equator than that.
Sydney is therefore unlikely to be safe.

There may be no such satellites over the Poles, since (IIRC) one gets a
typical sun-synchronous orbit with an inclination of 98 degrees. *And
there's little worth spying on at the North Pole, and the USA knows what
is at the South Pole. *So stay within 480 miles of a Pole for
comparative safety.

Earth rotation and 98 degress inclination covers most of the planet.
That is why EO Sats use that orbit. A spy satellite might more likely
be a GEO Sat over a particular area like the Middle East, China or
Russia. Or, be in a Molniya orbit for similar reasons. See:
http://en.wikipedia.org/wiki/Molniya_orbit

Eric