Sebastian Stabroth posted: >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. But since the orbits are "sun-synchronous", the solar perturbations to the inclination add up over time. The lunar perturbations tend to average out. October 2000: 1 26536U 00055A 00285.26312341 .00000648 00000-0 38534-3 0 321 2 26536 98.7917 229.5955 0009775 217.5542 142.5023 14.10912717 2794 August, 2001: 1 26536U 00055A 01227.70893451 .00000164 00000-0 11479-3 0 4521 2 26536 98.8298 172.4404 0011756 67.6276 292.6049 14.11209801 46294 June, 2002: 1 26536U 00055A 02170.92783292 .00000001 00000-0 24961-4 0 8710 2 26536 98.8702 116.5014 0009649 276.2171 83.7901 14.11702891 89773 The change in inclination from 98.79 to 98.87 degrees is due to solar perturbations. >The NOAA satellites have thrusters to compensate for altitude loss and perhaps >other small perturbing forces. There is no indication of any attempt to change the orbit of NOAA 16 at any time over the last 20 months to compensate for its decrease in altitude due to atmospheric drag. The change in mean motion from 14.109 just after launch to 14.117 at present seems reasonably close to linear considering the rather high (and varying) solar activity over this time span. Mike McCants ----------------------------------------------------------------- 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 - 16:16:57 PDT