Sebastian Stabroth wrote: > the perturbation of the Sun's gravity is very small compared > to other "anomalies" for this orbit type. The Moon's gravity > would have about the same small disturbing effect or even more. The force is small, but it builds up over time, causing the inclination to change significantly, which in turn causes the orbital plane to drift far from its original location. I found several scientific papers on the web that mention this as a limitation on the usefulness of data from certain of the NOAA sensors. > My guess is that there are two different altitudes: one for > the "afternoon" and one for the "morning" orbit. I don't know > the reason for this. I have found the reason on page 20 of this document: http://npoesslib.ipo.noaa.gov/techlib/doc103/doc103.pdf "Two nominal altitudes have been chosen: 833 km (450 n.mi.) and 870 km (470 n.m.). The choice between nominal altitudes will be made to keep the orbital periods of two operational satellites in similar orbits sufficiently different (1 minute) so that they do not both view the same point on the Earth at the same time each day." Ted Molczan ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/sat/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Tue Jun 25 2002 - 16:24:34 PDT