The thing about high eccentricity orbits is that the satellite spends considerably longer at round about the apogee position then around the perigee position. In the case of the Russian Molnyia satellites which are used for communication at high latitudes satellites are placed in a high eccentricity 24h orbit with a high inclination but at different positions in the orbit. This results in a fixed area in the sky that always has a Molnyia satellite creeping at apogee in it. As soon as it speeds up coming towards the planet again then it's neighbour enters the same area following behind. I believe the Molnyia system requires three operating Molnyia satellites in the same geometric orbit (differing only in their position at any one time). This allows high latitude places such as northern Russia the opportunity for fixed satellite dish satellite communication that lower latitude places take for granted with just one geostationary satellite. Marcus Massey (Lat 51deg, 29.578min : Lon 0deg, 04.318min) -----Original Message----- From: Tom Wagner [mailto:sciteach@mchsi.com] Sent: 09 June 2006 01:39 To: SeeSat-L@satobs.org Subject: Eccentricity About satellite orbit eccentricity. What's the advantage of a satellite having a permanent highly eccentric earth orbiting orbit? What general kind of satellites have them? I see that some Delta satellites do. The DELTA-4 R/B, although, not a working satellite, has an eccentricity in the TLE that's listed as being about 0.7! Thanks, Tom Iowa USA ------------------------------------------------------------------------ - Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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