The Spaceflight Meteorology Group

Postflight Mission Summary for STS-90

May 13, 1998

Space Shuttle Columbia landed at the Shuttle Landing Facility (SLF), Florida at 16:09 UTC, on Sunday, May 3, 1998, after almost sixteen days in orbit with the Nuero Lab as the prime payload.

Weather for launch day on April 17 was favorable over the CONUS sites with high pressure dominating weather over Florida and California. Strong subsidence aloft suppressed cloudiness over Florida.

The TAL sites were a different story as a strong low which developed in the Bay of Biscay on April 16th moved rapidly northeastward into the North Sea. The associated frontal boundary brought generally unstable and windy conditions to Zaragoza and Moron, Spain and Ben Guerir, Morocco as northwesterly flow persisted. All three sites were observed and forecast to be “NO GO” due to low ceilings. Crosswinds were also a factor at the Spanish sites and precipitation was expected at Zaragoza for the TAL abort time. Late in the count conditions began improving such that Ben Guerir and Moron were given a “GO”. Only Zaragoza was observed “NO GO” at launch time, but conditions there improved such that it was observed “GO” at what would have been the TAL abort time.

Following a one day delay due to hardware problems on the orbiter, Columbia lifted off at the opening of the two and one half hour launch window at 18:19:00 UTC, April 17. With some high level moisture present, pileus clouds were observed briefly around the vehicle as it lifted through the 30 000 foot level.

Toward the end of the Nuero Lab mission, mission managers met to decide whether to extend the mission by one day. SMG meteorologists expressed concern about possible deteriorating weather in Florida and California should a one day extension occur. NASA opted not to extend the mission.

Touchdown of Columbia occurred at the Shuttle Landing Facility (SLF), KSC, Florida at 16:09 UTC, May 3, after almost sixteen days in orbit. Even with the pristine weather at the SLF, mission controllers and SMG forecasters discussed the possibility of a reduced crosswind restriction of 10 knots due to the possible problem in cooling an on-board Auxiliary Power Unit (APU). However, the Flight Control Team held the cross wind limit at 15 knots, which is the standard End Of Mission (EOM) crosswind limit.

SMG forecasters held to a forecast of FEW clouds and unrestricted visibilities with west winds of generally 8 to 12 knots. The final touchdown observation reported FEW clouds at 7 000 feet, unrestricted visibilities, and surface winds of 230 04 P 11 knots.

Lead Meteorologist for STS-90 was Dan Bellue. Steve Sokol was the Assistant Lead, and Doris Rotzoll worked as the Lead Techniques Development Unit (TDU) Meteorologist.

Submitted by: Dan G. Bellue Frank C. Brody