Re: Incorrect Chandra TLE?

Tony Beresford (starman@camtech.net.au)
Thu, 19 Aug 1999 13:59:33 +0930

At 11:41 19/08/1999 , Ron Lee wrote:
>CXO
>1 25867U 99040B   99219.38932609 -.00000028  00000-0  00000+0 0   137
>2 25867  28.4718 194.5545 7750893 272.2645  23.4010  0.94210851   189
>CXO
>1 25867U 99040B   99216.69385420 -.00000056  00000-0  00000+0 0   110
>2 25867  28.4570 194.5520 8468509 270.6770 180.2770  0.39254669   134
>
>Maybe I am missing something but how did the mean motion go from 0.392
>to 0.942?    I suspect the top TLE is in error.
The set with meanmotion .392.. is in fact a later elset if you look at
the appropiate column. Its just that SPACECOM had to set the epoch
at the ascending node, which was unfortunately earlier the last one.
I have already pointed this problem out.  
An additional problem is that the TLE is not current. It doesnt represent
the position of the CXO, because it doesnt include the effect of the final
burn. The final orbit state vector was posted to Seesat by Jonathon Mcdowell,
and Ted Molczan posted the converted  TLE a few hours later
Chandra         15.0  4.0  0.0  4.2 d
1 25867U 99040  B 99219.45833333  .00000000  00000-0  00000-0 0    05
2 25867  28.4518 194.1107 8016020 271.0755 180.3370  0.37800574    01

Obviously USSPACECOM hasnt tracked it for the last 12 days or 4.5 revs, which
is a bit surprising as it is only mag 15.5 at apogee according to highfly
Tony Beresford