SB SAREX @ AMSAT $STS-79.007
STS-79 SAREX Update Number 7

Silver Spring, Maryland  USA
September 17, 1996 @ 2100 UTC

ATLANTIS ORBITAL SCHEDULE

Racing around the world in preparation for the scheduled linkup,
STS-79 Commander Bill Readdy and Pilot Terry Wilcutt conducted a
rendezvous burn at 0052 UTC today to refine Atlantis' approach to
the orbiting space complex.  Atlantis is currently closing in on
Mir at a rate of 500 nautical miles every orbit.

Here are the current keplerian elements for Atlantis (and Mir, see
below) as provided by Gil Carman WA5NOM at the NASA Johnson Space
Center.  The element set #907 for Atlantis is valid until the NC-4
burn on September 18 at 0046 UTC which will increase apogee and
perigee altitudes by about 2 n.mi.

STS-79
1 24324U 96057A   96261.67776106  .00058614  00000-0  11307-3 0  9074
2 24324  51.6509  18.3488 0037895 342.8253  17.1640 16.00511194   225

Satellite: STS-79
Catalog number: 24324
Epoch time:      96261.67776106   =     yrday.fracday
Element set:     907
Inclination:       51.6509 deg
RA of node:        18.3488 deg
Eccentricity:     .0037895
Arg of perigee:   342.8253 deg
Mean anomaly:      17.1640 deg
Mean motion:   16.00511194 rev/day
Decay rate:    5.86140E-04 rev/day^2
Epoch rev:              22
Checksum:              311

The next burn, NC-5, follows at 11:39 UTC, which will increase apogee
by an additional 40 n.mi.  The following two-line element set #909 is
based on the current predicted orbit after completion of the NC-4
and NC-5 burns.

STS-79
1 24324U 96057A   96262.48964145  .00049835  00000-0  85830-4 0  9096
2 24324  51.6541  14.0129 0092642 336.0560  23.6314 15.85643808   357

The orbit of Mir remains much more stable:

Mir
1 16609U 86017A   96261.39480309  .00002806  00000-0  37580-4 0  6691
2 16609  51.6523  19.4478 0009736 179.6485 180.4557 15.61936602604373

Satellite: Mir
Catalog number: 16609
Epoch time:      96261.39480309    =    (17-Sep-96   09:28:30.98 UTC)
Element set:     669
Inclination:       51.6523 deg
RA of node:        19.4478 deg       Semi-major axis: 3650.1932 n.mi.
Eccentricity:     .0009736           Apogee altitude:  209.8129 n.mi.
Arg of perigee:   179.6485 deg       Perigee altitude: 202.7053 n.mi.
Mean anomaly:     180.4557 deg       Altitude decay:   0.0044 n.mi./day
Mean motion:   15.61936602 rev/day   Apsidal rotation:   3.7529 deg/day
Decay rate:      2.806e-05 rev/day^2 Nodal regression:  -5.0362 deg/day
Epoch rev:           60437           Nodal period:      92.1318 min
Checksum:              336

For one's planning purposes courtesy of Gil Carman, here is the
orbital adjustment schedule for Atlantis covering the entire
mission as developed prior to launch.  This data will provide some
additional insight to the various Atlantis trim burns which will
make it necessary for new on-orbit element sets to be generated.
Actual time of launch was September 16 (Day 260) at 08:54:49 UTC.

STS-79 Prelaunch elements based on a launch of 16-Sep-96 08:53:49 UTC:

JSC-001 - 16-Sep-96 09:36:42 UTC to 16-Sep-96 12:34:46 UTC - OMS-2
JSC-002 - 16-Sep-96 12:34:46 UTC to 17-Sep-96 06:07:40 UTC - NC-1
JSC-003 - 17-Sep-96 06:07:40 UTC to 17-Sep-96 11:03:19 UTC - NPC
JSC-004 - 17-Sep-96 11:03:19 UTC to 18-Sep-96 00:33:07 UTC - NC-3
JSC-005 - 18-Sep-96 00:33:07 UTC to 18-Sep-96 11:35:43 UTC - NC-4
JSC-006 - 18-Sep-96 11:35:43 UTC to 18-Sep-96 23:00:49 UTC - NC-5
JSC-007 - 18-Sep-96 23:00:49 UTC to 19-Sep-96 00:32:53 UTC - NC-6
JSC-008 - 19-Sep-96 00:32:53 UTC to 19-Sep-96 01:55:00 UTC - TI
JSC-009 - 19-Sep-96 01:55:00 UTC to 19-Sep-96 03:16:49 UTC - INTERCEPT
JSC-010 - 19-Sep-96 03:16:49 UTC to 24-Sep-96 03:15:48 UTC - DOCKING
JSC-011 - 24-Sep-96 03:15:48 UTC to 25-Sep-96 07:53:49 UTC - SEP BURN
JSC-012 - 25-Sep-96 07:53:49 UTC to 25-Sep-96 12:13:00 UTC  REBOOST DTO

Deorbit:  25-Sep-96 12:13 UTC  (orbit 144)
Landing:  25-Sep-96 13:13 UTC  (orbit 145)

Obviously, Mir rendezvous orbits for the space shuttle are very
dynamic.  Watch for further SAREX bulletins as the mission develops.

[Amateurs are encouraged to relay these SAREX messages to their
local packet BBS as long as the Bulletin IDentification (BID) is
preserved.  The BID is the character string starting with the dollar
sign ($), for example as in "SB SAREX @ AMSAT $STS-79.007" without
the quotation marks.]

Submitted by Pat Kilroy, WD8LAQ for Frank H. Bauer, KA3HDO and the
SAREX Working Group.

/EX

========================================================================
Patrick L. Kilroy                  Phone:   301-286-5910
Engineer                           Fax:     301-286-1695
NASA/Goddard Space Flight Center   E-mail:  pat.kilroy@gsfc.nasa.gov
Building 6, Code 311               WWW URL: http://arioch.gsfc.nasa.gov/
Greenbelt, Maryland  20771                  310/310.html
=========================================================================
					September 17, 1996 @ 2300 UTC

The STS-79 element set #907 given in SAREX bulletin STS-79.007 can
be used for amateur tracking purposes after the NC-4 burn scheduled
for September 18 at 0046 UTC and until the scheduled NC-5 burn on
September 18 at 1139 UTC.

I should have noted this in the bulletin.  (That's why no element
set #908 was offered.)

Happy space DXing!

Pat WD8LAQ
AMSAT Volunteer

P.S. I hope this orbital mechanics stuff is not too confusing to the
masses.  (The last couple sentences before the [] note in the bulletin
says it all!)  Thank you again to Gil for all this neat stuff!
.

.