1. Orbits from observations
Lacrosse 5 0.0 0.0 0.0 3.4 v
1 71001U 05016A 05121.30567409 .00001317 00000-0 10000-3 0 03
2 71001 57.0006 128.1443 0165730 17.3893 343.2720 14.91442536 05
Arc 2005 Apr 30.04 - May 01.33, WRMS residuals = 0.040 deg
Lacrosse 5 r 9.8 3.0 0.0 4.8 v
1 71004U 05016B 05121.30509779 .00001315 00000-0 10000-3 0 00
2 71004 56.9969 128.1380 0159329 16.8137 343.8090 14.92106992 06
Arc 2005 Apr 30.04 - May 01.12, WRMS residuals = 0.029 deg
2. Estimated Orbit of 05016A after Circularization
The following search orbits are based on the assumption that the payload will
circularize its orbit about 48 h after launch, on an apogee pass within range of
Diego Garcia, as was the case with Lacrosses 2, 3 and 4.
In the case of 05016A, that would be tonight, 2005 May 02 near 01:55:35 UTC.
I note that 05016A's initial apogee appears to be greater than that of any of
its predecessors:
km
88106B 687
91017A 678
97064A 676
00047A 689
05016A 709
Assuming 05016A's higher apogee is intentional, and a nearly circular final
orbit, then the following search orbit applies:
703 X 709 km
1 70000U 05122.08026620 .00000044 00000-0 10000-4 0 07
2 70000 57.0006 125.0644 0004000 18.7493 182.1000 14.56000000 03
In the event 05016A manoeuvres to replicate 97064A's initial circularized orbit,
the following applies:
670 X 676 km
1 70000U 05122.08026621 .00000044 00000-0 10000-4 0 08
2 70000 57.0006 125.0644 0004000 18.7493 182.1000 14.66200000 06
I recommend the following observational plan.
1. Prior to 2005 May 02 at 01:55:35 UTC, assume 05016A will not have manoeuvred,
so use the 14.9144 rev/d elset derived from observations.
2. After 2005 May 02 at 01:55:35 UTC, assume 05016A may or may not have
manoeuvred, so look for it first in the 14.9144 rev/d orbit derived from
observations. If it fails to appear, then expect its earliest pass in the 14.662
rev/d search orbit, and its latest pass in the 14.56 rev/d orbit.
It is recommended to plot all three predicted tracks.
Ted Molczan
-------------------------------------------------------------------------
Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:
http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Sun May 01 2005 - 11:34:56 EDT