Discovery launch and elsets

Walter Nissen (dk058@cleveland.Freenet.Edu)
Thu, 13 Jul 1995 12:53:24 -0400

Perhaps the fact that the crew of Discovery is an all-Ohio crew (Gov. 
George Voinivich officially designated the one non-Ohio-native crewman as 
an honorary Ohioan) and Ohio's traditional dominance of pioneering flight 
(Wilbur Wright, Orville Wright, John Glenn and Neil Armstrong are all 
native Ohioans) have led to the happy circumstance of somewhat adequate 
broadcast coverage of the mission. 
 
I just watched the successful launch of STS-70 on local Cleveland 
broadcast TV less than one minute later than I had anticipated (there was 
a very brief hold at T-31s, just as the switch to auto seq start was to 
take place, followed by audio of a consultation and a clear to pickup the 
count and a synchronization of the pickup; later explained as a voltage 
fluctuation).  Liftoff at roughly 950713 134156.  My son is working at 
NASA Lewis this summer, so I suppose he was watching NASA Select from the 
auditorium with the fringes of the crew families (the immediate families 
were mostly at the Cape), or the like.  Still pretty emotional after all 
these years, and "Roger, go at throttle-up" still isn't a routine phrase. 
The roar of the engines triggered annoying car alarms in the vicinity of 
the Cleveland reporter's remote. 
 
Gary Morris' shuttle-elements mailing list distributed these anticipated 
elsets in the past week: 
STS70 rev 2 JSC-001  --  13Jul95 14:23:21  to  13Jul95 20:08:18 UTC 
1 99970U          95194.62046583 -.00253378  00000-0 -85192-3 0    18 
2 99970  28.4669 326.3673 0004615 286.6946  73.3195 15.91124517    24 
STS70 rev 6 JSC-002  --  13Jul95 20:08:18  to  14Jul95 19:06:40 UTC 
1 99970U          95194.87144219 -.00026652  00000-0 -11039-3 0    23 
2 99970  28.4677 324.4866 0023185 193.1645 166.8399 15.85477873    64 
STS70 rev21 JSC-003  --  14Jul95 19:06:40  to  21Jul95 10:51:00 UTC 
1 99970U          95195.81551904  .00017899  00000-0  55675-4 0    38 
2 99970  28.4680 317.4832 0016417 154.9557 205.1895 15.89705110   217 
 
>From http://shuttle.nasa.gov, Mission at a Glance followed by Status at 
a Glance will get you a calculation of the actual position of the 
shuttle and from the Shuttle State Vector these elsets: 
Discovery post oms-2 
1 99999U          95194.59955081  .00073094  00000+0  25911-3 0    14 
2 99999  28.4683 326.5270 0004609 282.5587 317.3931 15.91070879    14 
Discovery post sep-2 
1 99999U          95194.83987672  .00073094  00000+0  30636-3 0    23 
2 99999  28.4648 324.7409 0023428 195.3255 344.1374 15.85409287    57 
Discovery post oms-3 
1 99999U          95195.79961896  .00073094  00000+0  30704-3 0    36 
2 99999  28.4657 317.6196 0021186 160.5927 108.3986 15.89732482   206 
 
And these last were accompanied by, respectively, 
Vector time (GMT) :  194:14:23:21.190 
This vector is valid for prediction purposes until 194:20: 0:  .0 GMT 
Vector time (GMT) :  194:20: 9:25.349 
This vector is valid for prediction purposes until 195:19: 0:  .0 GMT 
Vector time (GMT) :  195:19:11:27.078 
This vector is valid for prediction purposes until 197:19: 0:  .0 GMT 
 
This advance information is apparently the best ever made available and 
somebody unknown to me at the Flight Dynamics Office at Johnson deserves 
our fervent thanks. 
 
Regrettably, prospects for viewing from as far north as 41 degrees seem 
poor at best.  But, even so, has someone already analyzed the significance 
and usefulness of these various elsets?  I'm particularly suspicious of 
the negative and large positive ndot2's.  Seems to me a reasonable ndot2 
might be .00008 or a little less.  Of course, as subsequent elsets are
released by SPACECOM the validity of ndot2 can be tracked against the
successive MMs.

Cheers.