Re**3: Updated TiPS TLEs

Mike McCants (mikem@fc.net)
Sat, 3 May 1997 11:16:52 -0500 (CDT)

Craig Cholar wrote:

>I'd like to thank Mike McCants for posting the TiPS elements.

Hello Craig,

You should thank me only if those elements are correct.  :-)

>Had I checked my notes more carefully before posting, I would have discovered
>the it wasn't the Molczan TiPs elements that were off by 20 seconds or more,
>but other, more recent ones I had obtained elsewhere.

Obviously TiPS gives us a chance to compare "our" elsets against NORADs.
Does the radar have "problems" with such an extended object with a reflector
at each end?

NORAD elsets:
1 00001U 00000A   97119.38194444 -.00000634  00000 0  -7925-2 0 00000
2 00001  63.4285  62.4140 0030422 357.0179 118.6096 13.63946621 41203
1 00002U 00000  A 97121.36111111 -.00000535  00000 0  -6687-2 0 0000
2 00002  63.4287  57.1707 0030812 356.8825 116.8365 13.63948078 4147
1 00003U 00000  A 97122.52083333 -.00000415  00000 0  -5191-2 0 0000
2 00003  63.4293  54.0968 0031217 357.2047  50.9738 13.63948676 4163

Note that the change in mean motion, +0.000020 divided by (3 days
* 2) gives 0.000003 for a drag term, which agrees with my claim that
the drag has remained constant and positive.  Note that the NORAD
negative drag term is now changing gradually toward the correct
value.

I would like to have previous NORAD elsets on TiPS for the last month
or so to see if there is some "discontinuity" in them.  The tether is
a survivability experiment, so at some point we can expect it to break
into two pieces.  (Please send via private email to mikem@fc.net).

"Mature" elsets:
1 00004U 96029  F 97 67.44929521 0.00000280  00000-0  35079-3 0    05
2 00004  63.4294 199.9987 0024081   2.2987 357.7013 13.63907691    00
1 00005U 96029  F 97107.40770066 0.00000285  00000-0  35692-3 0    00
2 00005  63.4304  94.1625 0024001   0.1002 359.8998 13.63930668    09

>I would have seen their accuracy and wouldn't have bothered posting the
>supposedly 'improved' one.

But there really is a non-zero discrepancy between the 97067 and 97107
elsets that I have derived and the NORAD elsets.  Here is a rough
prediction for you for this evening:

  36.700 121.800  Craig Cholar

***  1997 May   4  Sun morning  *** Times are AM PDT  ***  2046  521

 H  M  S  Tim Al Azi C Dir  Mag Dys F  Hgt Shd  Rng  EW Phs  R A   Dec Elset #
 0  8 26   .0 53 327   355  7.5   2 4  649  26  783 1.1  90 1055  61.7   3
 0  8 26   .0 53 327   353  7.5   3 4  649  26  783 1.1  90 1055  61.7   2
 0  8 26   .0 53 327   355  7.5   5 4  649  26  783 1.1  90 1055  61.7   1
 0  8 33   .1 53 327     0  7.5  17 4  646  22  780 1.1  89 1055  61.8   5
 0  8 35   .7 53 327     0  7.5  57 4  646  22  779 1.1  89 1055  61.8   4
(This is near shadow entry.)

There is a 7 second discrepancy between the 3 recent NORAD elsets
and my 97107 elset based on observations through April 17.  Either
NORAD's clocks are wrong (:-), or something has happened in the last
two weeks that has changed the orbit in some way.  That is why I would
like to have elsets from the last few weeks.

>older elsets are hand-crafted by the experts, who, unlike myself, know
>what they doing.  :-)

In general, a NORAD radar observation from today is better than an
elset based on observations from two weeks ago.  :-)

But when the computer generates strange negative drag terms, inquiring
minds would like to know why.  :-)

I'd like to thank Craig Cholar for bringing this interesting question
to my attention.

Mike McCants
Austin, TX