SB SAREX @ AMSAT $STS-78.015
STS-78 SAREX Update and Keps 15

Silver Spring, Maryland USA
June 26, 1996 @ 23:00 UTC

After a half day of off-duty relaxation, Columbia's crew went back to
work on the 41 science investigations associated with the STS-78 Life
and Microgravity Spacelab mission.

Pilot Kevin Kregel discussed the progress of the fifth Shuttle
mission of the year with students at Bethlehem Central Senior High
School in Delmar, N.Y., using the Shuttle Amateur Radio Experiment
(SAREX).  Payload Specialist Bob Thirsk used the ham radio gear to
make contact with students at the Saskatoon Public AerospaCe
Education (S.P.A.C.E.) school in Saskatoon, Saskatchewan in Canada
via the AMSAT telebridge.

AMSAT member Gil Carman, WA5NOM, reports that it's important on this
flight to keep updated to the latest elements.  Even though there are
no orbit adjust burns, the low altitude and the attitude changes
between tail down and tail forward make the drag variations very
significant.

For example, element set #909 is 5 seconds later than set #908 now,
and will be 14 seconds later by this time tomorrow.  Ten seconds is
about the maximum allowable tracking error for a high elevation
pass on orbits this low in altitude to keep it in a 35 degree (e.g.,
KLM-22C main lobe) antenna pattern.  Of course, amateurs who use a
lower gain antenna need not be concerned as much.  The orbiter is
rising EARLIER than earlier element sets predict, sometimes by a
matter of minutes.

Here is the latest Keplerian element set courtesy Gil Carman in
Houston:

STS-78
1 23931U 96036A   96178.72367356  .00118242  00000-0  20691-3 0  9092
2 23931  39.0147 329.0657 0006999 312.4350  47.6036 16.01748976   990

Satellite: STS-78
Catalog number: 23931
Epoch time:      96178.72367356   =     yrday.fracday
Element set:     909
Inclination:       39.0147 deg
RA of node:       329.0657 deg
Eccentricity:     .0006999
Arg of perigee:   312.4350 deg
Mean anomaly:      47.6036 deg
Mean motion:   16.01748976 rev/day
Decay rate:    1.18242E-03 rev/day^2
Epoch rev:              99
Checksum:              346

The oldest space shuttle in the fleet continues to perform in
excellent fashion on its 20th mission, with no significant systems
problems being tracked by flight controllers.

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

/EX