The countdown includes 28 hours and 18 minutes of built-in hold time leading to the opening of the launch window at 3:18 p.m. (EST) on Feb. 22. The launch window extends for 2 hours, 30 minutes.
STS-75 is the second Space Shuttle mission for 1996. It will be the 19th flight of the Shuttle Columbia and the 75th flight overall in NASA’s Space Shuttle program.
The primary objectives of mission STS-75 are to conduct scientific investigations of the Tethered Satellite System (TSS-1R) and the United States Microgravity Payload (USMP-3).
Columbia last flew in October/November 1995 on Space Shuttle mission STS-73. Following a KSC landing, Columbia was transported to Orbiter Processing Facility (OPF) bay 2 in preparation for this mission. Columbia was rolled out of the OPF on Jan. 23 and mated with the external tank and solid rocket boosters in the Vehicle Assembly Building. The Shuttle stack was then transported to Pad 39-B on Jan. 29.
The STS-75 crew are: Commander Andy Allen; Pilot Scott Horowitz; Mission Specialists Jeff Hoffman, Maurizo Cheli, Claude Nicollier, and Franklin Chang-Diaz; and Payload Specialist Umberto Guidoni.
The crew is scheduled to arrive at KSC at about 3:30 p.m. Monday. Their activities at KSC prior to launch include equipment fit checks, medical examinations and opportunities to fly in the Shuttle Training Aircraft.
Enter first planned built-in hold at T-27 hours for duration of four hours (8 a.m.)
* Clear launch pad of all personnel
* Perform test of the vehicle's pyrotechnic initiator controllers
Resume countdown (12 noon)
* Begin the 12-hour operation to load cryogenic reactants into Columbia's fuel cell storage tanks.
Enter eight-hour built-in hold at T-19 hours (8 p.m.)
* After cryogenic loading operations, re-open the pad
* Resume orbiter and ground support equipment close-outs
* Begin installation of mission specialists' seats in crew cabin
* Start final preparations of the Shuttle's three main engines for
main propellant tanking and flight
* Activate flight controls and navigation systems
* Close-out the tail service masts on the mobile launcher platform
* Perform orbiter ascent switch list in crew cabin
* Install film in numerous cameras on the launch pad
* Activate the orbiter's communications systems
* Activate orbiter's inertial measurement units
Enter planned hold at T-11 hours for 12 hours, 58 minutes (12 noon)
* Demate orbiter mid-body umbilical unit and retract into Fixed
Service Structure
* Fill pad sound suppression system water tank
* Safety personnel conduct debris walkdown
* Move Rotating Service Structure (RSS) to the park position (7 p.m.)
* Continue final stowage of mid-deck experiments and flight crew equipment
Launch Day (Thursday, Feb. 22)
Resume countdown (12:58 a.m.)
* Start fuel cell flow-through purge
* Install time-critical flight crew equipment
* Perform pre-ingress switch list
* Activate the orbiter's fuel cells
* Configure communications at Mission Control in Houston for launch
* Activate the solid rocket boosters joint heaters
* Clear the blast danger area of all non-essential personnel
* Switch Columbia's purge air to gaseous nitrogen
* Activate auxiliary power unit heaters
Enter planned one-hour built-in hold at T-6 hours (5:58 a.m.)
* Launch team verifies no violations of launch commit criteria prior
to loading cryogenics into external tank
* Verify pad is clear of all personnel
Resume countdown (6:58 a.m.)
* Begin loading the external tank with cryogenic propellants (6:58 a.m.)
* Perform inertial measurement unit preflight calibration
* Align Merritt Island Launch Area (MILA) tracking antennas
* Complete filling the external tank with its flight load of liquid
hydrogen and liquid oxygen propellants (10 a.m.)
Enter planned two-hour built-in hold at T-3 hours (9:58 a.m.)
* Perform open loop test with Eastern Range
* Conduct gimbal profile checks of orbital maneuvering system engines
* Close-out crew and Final Inspection Team proceed to Launch Pad 39-B
* Flight crew departs Operations and Checkout Building for Launch Pad
39-B (11:53 a.m.)
Resume countdown at T-3 hours (11:58 a.m.)
* Complete close-out preparations in the white room
* Check cockpit switch configurations
* Flight crew enters orbiter
* Astronauts perform air-to-ground voice checks with Launch Control and
Mission Control
* Close Columbia's crew hatch
* Begin Eastern Range final network open loop command checks
* Perform hatch seal and cabin leak checks
* Complete white room close-out
* Close-out crew moves to fallback area
* Primary ascent guidance data is transferred to the backup flight system
Enter planned 10-minute built-in hold at T-20 minutes (2:38 p.m.)
* NASA Test Director conducts final launch team briefings
Resume countdown (2:48 p.m.)
* Transition the orbiter's onboard computers to launch configuration
* Start fuel cell thermal conditioning
* Close orbiter cabin vent valves
* Transition backup flight system to launch configuration
Enter final 10-minute built-in hold at T-9 minutes (2:59 p.m.)
* Launch Director, Mission Management Team and NASA Test Director conduct final polls for go/no go to launch
Resume countdown at T-9 minutes (3:09 p.m.)
* Start automatic ground launch sequencer (T-9:00 minutes)
* Retract orbiter crew access arm (T-7:30)
* Start mission recorders (T-5:30)
* Start Auxiliary Power Units (T-5:00)
* Arm SRB and ET range safety safe and arm devices (T-5:00)
* Start liquid oxygen drainback (T-4:55)
* Start orbiter aerosurface profile test (T-3:55)
* Start main engine gimbal profile test (T-3:30)
* Pressurize liquid oxygen tank (T-2:55)
* Begin retraction of the gaseous oxygen vent arm (T-2:55)
* Fuel cells to internal reactants (T-2:35)
* Pressurize liquid hydrogen tank (T-1:57)
* Deactivate SRB joint heaters (T-1:00)
* Orbiter transfers from ground to internal power (T-0:50 seconds)
* Ground Launch Sequencer go for auto sequence start (T-0:31 seconds)
* Ignition of three Space Shuttle main engines (T-6.6 seconds)
* SRB ignition and liftoff (T-0)
SUMMARY OF BUILT-IN HOLDS FOR STS-75 T-TIME LENGTH OF HOLD HOLD BEGINS HOLD ENDS T-27 hours 4 hours 8:00 a.m. Tuesday 12:00 noon Tuesday T-19 hours 8 hours 8:00 p.m. Tuesday 4:00 a.m. Wednesday T-11 hours 12 hours, 58 minutes 12:00 noon Wednesday 12:58 a.m. Thursday T-6 hours 1 hour 5:58 a.m. Thursday 6:58 a.m. Thursday T-3 hours 2 hours 9:58 a.m. Thursday 11:58 a.m. Thursday T-20 minutes 10 minutes 2:38 p.m. Thursday 2:48 p.m. Thursday T-9 minutes 10 minutes 2:59 p.m. Thursday 3:09 p.m. Thursday CREW FOR MISSION STS-75 Andy Allen Commander (CDR) White Team Scott Horowitz Pilot (PLT) Red Team Jeff Hoffman Mission Specialist (MS1) White Team Maurizo Cheli Mission Specialist (MS2) Red Team Claude Nicollier Mission Specialist (MS3) Blue Team Franklin Chang-Diaz Mission Specialist (MS4) Blue Team Umberto Guidoni Payload Specialist (PS1) Red Team SUMMARY OF STS-75 LAUNCH DAY CREW ACTIVITIES Thursday, Feb. 22 3:00 a.m. Wake up (Red Team) 3:30 a.m. Breakfast (Red Team) 7:30 a.m. Wake up (White Team) 8:00 a.m. Breakfast (White Team) and Lunch (Red Team) 10:13 a.m. Wake up (Blue Team) * 10:43 a.m. Crew Photo and Meal (Red, White and Blue Teams) 11:13 a.m. Weather briefing (CDR, PLT, MS2) 11:13 a.m. Don launch and entry suits (MS1, MS3, MS4, PS1) 11:23 a.m. Don launch and entry suits (CDR, PLT, MS2) * 11:40 a.m. Crew suiting photo * 11:53 a.m. Depart for Launch Pad 39-B * 12:33 p.m. Arrive at white room and begin orbiter ingress * 1:48 p.m. Close crew hatch * 3:18 p.m. Launch* Televised events (times may vary slightly)