The Spaceflight Meteorology Group
Postflight Mission Summary for STS-88
January 6, 1999
International Space Station Construction Begins
The Space Shuttle Endeavour landed at Floridas Kennedy Space
Center (KSC) Shuttle Landing Facility at 10:53 PM EST (0353 UTC) on Monday, December 14,
1998 after a very successful 11 day mission. Endeavour launched from KSCs Pad 39A on
Friday, December 4, at 3:35 AM EST (0835 UTC) after a one day delay. Mission objectives
included a rendezvous with the Russian built Zarya segment which had been launched in
November, moving the US built node 1 (Unity) upon Endeavours docking mechanism and
docking the Shuttle/Unity to Zarya, and completing three space walks to make additional
connections on the new International Space Station. All objectives were accomplished.
The planned launch day had been Thursday, December 3rd but an
electrical problem late in the launch count delayed the launch one day. Prior to the
electrical problem, the weather had been a key factor in the launch decision. A high
pressure system covered the southeast US and southwestern Atlantic. Showers developed over
the water and moved towards the Florida coast in the southeast flow. Moderate rain showers
moved into the launch (and emergency return landing area) an hour prior to the scheduled
launch. There are stand-off distances for rain showers that must be met for the launch
site and also for the landing site at KSC, in the event of a launch abort. The showers
cleared the launch area minutes before the scheduled launch, but were predicted to be near
the stand-off distance limit for landing at return-to-launch site (RTLS) abort landing
time. At the final decision point, the observed and forecast RTLS landing weather was
No-Go. However, this became a moot point when the electrical problem occurred. For the
next days launch attempt, the KSC weather was better, with scattered low clouds and
no showers in the KSC area. One of the three TAL sites had acceptable weather. Only one
Go TAL site is required for launch. Endeavor launched on time at 0835 UTC
December 4, at the opening of the 5 minute launch window.
Weather also played an important role on the December 14 landing day.
An upper level trough moving into the southeast US caused a surface low pressure system to
develop off the Florida coast, east of KSC. A shield of low clouds developed around the
low and spread west over eastern Florida about 15 hours prior to landing. The northeast
movement of the low and daytime heating eroded the clouds over the land during the day. By
sunset, the edge of the cloud shield was along the coast at KSC. The SMG landing forecast
called for scattered low clouds at landing time. The forecast also included a chance of
ceilings for the possibility that the cloud deck would develop westward under the
inversion as temperatures dropped. As the landing count continued, the weather
reconnaissance aircraft and infrared satellite imagery showed very slow eastward movement
of the cloud shield. At about 1 hour before the de-orbit burn, or 2 hours before landing,
the clouds continued to show a slow eastward progression and the chance of low cloud
ceilings at KSC was dropped from the SMG forecast, making the landing forecast a
Go. Endeavour landed under mostly clear skies.
Mission Lead Forecaster for STS-88 was Karl A. Silverman, working his
31st mission, 5th as Lead. Richard Lafosse was Assistant Lead and Doris Rotzoll worked as
the Lead Techniques Development Unit Meteorologist.
Karl A. Silverman
10th night landing.
17 KSC landings in a row.
6 on-time landings in a row.
25 KSC landings out of the past 30.
KSC landing total is now 46 which exceeds EDW total of 45. (WSSH = 1)
Only the 2nd KSC landing with Clear Skies reported. The other was STS-50.
Last KEDW landing was 3/31/96 (STS-76).