When Starshine 1 was deployed, NASA had included its predicted deployment TLE
on their Realtime Date web page for the mission involved (I've forgotten
which STS number that was). Using that TLE, along with the predicted shuttle
TLE in effect at the time, I found Starshine 1 should precede the shuttle by
about five degrees when they passed overhead here a few hours after
deployment. Sure enough when they came by, there it was -- five degrees
infront, flashing once every 20-30 seconds or so.
Unfortunately, this morning when I checked NASA's predicted shuttle TLEs,
there was no TLE for Starshine 2's deployment. I wrote NASA's Jonathan
Weever to ask about it. This is what I was told:
[Jonathan Weaver]:
I dont have the manual flexability that I used to regarding
posting additional deployement orbital elements, etc...
because we now use an automated Java script to build the
orbital elements ephemerides for the STS and the ISS.
I would recommend the following: Based on the deployment
time for Starshine 2, just use the STS orbital elements file
which is closest in UTC time to the deployment time and that
will model the initial starshine deployment trajectory profile.
It will then be given a catalog number by USSPACECOMMAND,
and then you can get future TLE's for starshine from available
websites.
Taking his advice, I went to the NASA TV Schedule web page:
http://spaceflight.nasa.gov/realdata/nasatv/schedule.html
There I found Starshine 2 is scheduled for deployment on orbit no. 153,
Saturday, Dec. 15, at 16:02 GMT.
With that, I went to NASA's shuttle Realtime Date Orbital Elements page --
http://spaceflight.nasa.gov/realdata/elements/index.html
-- to find the predicted shuttle TLE in effect for or preceding orbit 153.
That turned out to be orbit 139 (coasting arc #22):
SHUTTLE (Starshine 2 deployment)
1 99108U 01348.79325464 .00071000 00000-0 10050-3 0 9215
2 99108 51.6364 259.9170 0018465 94.2553 266.0713 15.60331700 1405
It happens the shuttle will do an orbit adjustment following the deployment
of Starshine 2, with Coasting Arc #23, beginning Orbit 154. This has a
predicted TLE of
SHUTTLE (orbit 154, post deployment)
1 99108U 01349.75392617 .00071000 00000-0 10050-3 0 9227
2 99108 51.6359 255.0818 0018573 97.8471 262.4794 15.60398466 1550
Using these two TLEs to model the passes of Starshine 2 and STS-108,
respectively, occurring later that evening, produced a gap between them of
under 1 degree, as viewed from my home in Maryland. Unfortunately, from
here they would also barely skim 9 degrees above the NNW horizon.
However, assuming nominal deploy, those viewing from south of Hudson Bay
would see them pass through the zenith about 3 degrees apart.
One concern with this, though, is that Starshine 1 was deployed downward, as
I recall. In so doing, it orbited slight faster than the shuttle each
revolution. Assuming this is the case with Starshine 2, I would expect the
gap between them, on the evening of Dec. 15th, would be wider than shown
using the two TLEs above. How much wider, I can't say. But since
deployment would have occurred only seven hours earlier, I would hope not a
great deal wider.
[Questions: Does anyone know what magnitude the Starshine 2 flashes may
reach? Does anyone know how long after deployment US Space Command might
release its TLE for Starshine 2?]
Clear skies,
Jim Cook
Germantown, MD
39.3N, 77.2W
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