- VEHICLE: Columbia/OV-102
- LOCATION: Launch Pad 39B
- TARGET KSC LAUNCH DATE/TIME: July 22, 1999 at 12:28 a.m. EDT
- TARGET KSC LANDING DATE/TIME: July 26, 1999 at 11:24 p.m. EDT
- LAUNCH WINDOW: 46 minutes
- MISSION DURATION: 4 days, 23 hours
- CREW: Collins, Ashby, Hawley, Coleman, Tognini
- ORBITAL ALTITUDE and INCLINATION: 153 nautical miles/28.45 degrees
- External tank loading operations begin again (July 21 at about 3:38 p.m.)
TUESDAY, JULY 20, 1999 (6:51 PM EDT)
LAUNCH-2 DAYS
STS-93 -- Chandra X-ray Observatory
NOTE: Following thorough evaluation of Space Shuttle Columbia's main propulsion system and hazardous gas detection system, Shuttle managers are confident in their readiness to attempt launch again on July 22 at 12:28 a.m. Engineers reviewed data last night and today that confirmed that a hydrogen leak did not cause the indication at T-8 seconds on the countdown clock. They have also confirmed that the hazardous gas detection system is working normally.
Draining of liquid oxygen from the external tank was complete at 2:54 a.m. today and liquid hydrogen draining concluded at 4:03 a.m. Boil-off of residual propellants will conclude by midnight tonight. Today workers are establishing access to the external hydrogen burn-off ignitors at Launch Pad 39B and the 4-hour ignitor replacement effort begins at about 3 a.m. tomorrow. The launch team will begin reloading the external tank with 500,000 gallons of liquid propellant at about 3:38 p.m. tomorrow. Workers have removed 8 of the middeck experiments for servicing and will reinstall the secondary payloads tomorrow. The Chandra/IUS payload is ready for Thursday's launch and remains powered up in the payload bay.
Weather forecasters indicate only a 10 percent chance that weather could prohibit Thursday's launch attempt. The forecast calls for few clouds at 2,500 feet and 25,000 feet; visibility at 7 miles; winds from the Southeast at 6 peaking to 8 knots; temperature at 80 degrees F and relative humidity at 86 percent.
STS-93 SCHEDULED OPERATIONAL MILESTONES (dates are target only):
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