The Spaceflight Meteorology Group
Postflight Mission Summary for STS-94
July 31, 1997
Space Shuttle Columbia landed at the Shuttle Landing Facility (SLF), Florida at 10:47
UTC, on Thursday, July 17, 1997, after the seven person crew successfully completed their
"virtually perfect scientific mission" of sixteen days. STS-94 was the reflight
of the April, 1997, STS-83 Mission, which was shortened prematurely due to a fuel cell
problem.
Weather for launch day proved to be exciting. Attempting a launch in Florida in the
middle of the afternoon in July always presents a challenge. Surface high pressure over
Florida and the Gulf of Mexico persisted as a weak upper level trough remained over the
eastern US. Winds aloft were generally westerly. Thunderstorms developed along the western
coast of Florida and moved east southeastward. Cumulus fields developed as surface heating
increased over the land. Showers and thunderstorms developed over central Florida in the
late morning and early afternoon hours. As launch time approached these thunderstorms
continued moving east southeastward near the southwest portion of the 20 NM circle
surrounding the SLF. Rainshowers developed within a hour of launch northwest of the SLF
just beyond the 20 NM circle. After the weather recon pilot reported this activity was
dissipating and returns from the Melbourne WSR88D confirmed no further development, the
RTLS forecast was amended at 17:50 UTC to remove "TSRA WI 20 NM". The count was
picked up at the T-9 Minute hold. Two minutes from launch, forecasters at the Range
Operations Control notified SMG that the Lightning Detection And Ranging (LDAR) system was
detecting lightning from a cell approximately 18 NM south southwest of the SLF. SMG
notified the Flight Director that this activity was expected to continue moving away from
the SLF and would not impact RTLS.
At the TAL sites a weak surface low pressure area was present to the southwest of Spain
and was expected to remain nearly stationary and produce little weather for Ben Guerir,
Morocco. Surface winds did approach crosswind limits there, but these limits were never
exceeded. At Banjul, The Gambia, the other TAL site, a low cloud ceiling developed for
about one hour during the launch count, but moved out of the area. Convective complexes
developing over central Africa were expected to produce a threat of "TSRA WI 20
NM" for Banjul. As the launch count progressed, these thunderstorms remained beyond
the approaches to Banjul, and were removed from the forecast. The weather recon pilot
reported "HAZE aloft, but GO, with a reduced slant range visibility.
Columbia lifted off at 18:02 UTC, after a twelve minute wait (due to weather concerns)
in the opening of the two and one half hour launch window. With ample high level moisture
present, pileus clouds were observed around the vehicle as it lifted through the 30,000
foot level.
The Microgravity Lab was flown for 16 days. The mission, described by the NASA Shuttle
Program Manager, Tommy Holloway, as "a virtually perfect scientific mission,"
far exceeded the scientific communitys data collection expectations.
Touchdown of Columbia occurred at the Shuttle Landing Facility (SLF), KSC, Florida at
10:47 UTC, July 17, after sixteen days in orbit. The initial weather concern was for
visibility restrictions due to fog. With light winds and high dewpoint temperatures a risk
of fog development existed. As on launch day, winds aloft were blowing offshore. Showers
in the Gulfstream were persistent. Weak boundaries from the land breeze and out-flow from
earlier convection collided and produced a shower near Patrick AFB that developed into a
short-lived thunderstorm three hours prior to the de-orbit burn decision. The land breeze
continued moving offshore. At 07:50 UTC, SMG updated the forecast to remove fog, due
primarily to sufficient wind velocity and mixing in the surface-to-500 foot layer.
However, weak showers persisted offshore through the final hour leading to the de-orbit
burn decision. At 09:30 UTC, just before the de-orbit burn decision, SMG updated the
forecast to include "showers 20 to 30 NM offshore." The Flight Director
determined that this would not produce an impact to landing and gave a "GO" for
the de-orbit burn at 09:36 UTC. Columbia touched down without incident. Visibility at
landing was 8 miles in BCFG (Fog Patches). Weather remained favorable through post landing
operations.
Lead Meteorologist for STS-94 was Dan Bellue. Tim Garner was the Assistant Lead, and
Mark Keehn worked as the Lead Techniques Development Unit (TDU) Meteorologist. Richard
Lafosse worked as the Radar Meteorologist. This marked the fourth time that this team of
meteorologists has worked a shuttle launch and landing together.
Submitted by:
Dan G. Bellue and Frank C. Brody
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