The countdown includes 31 hours and 30 minutes of built-in hold time leading to the opening of the launch window at 6:30 a.m. (EDT) on May 19. The launch window extends for 2 1/2 hours.
STS-77 is the fourth Space Shuttle mission of 1996. This will be the 11th flight of the orbiter Endeavour and the 77th flight overall in NASA’s Space Shuttle program.
Endeavour was rolled out of Orbiter Processing Facility bay 3 on April 8 and mated with the external tank and solid rocket boosters in the Vehicle Assembly Building. The Shuttle stack was then transported to Pad 39B on April 16. Endeavour last flew on a mission to retrieve a Japanese satellite in January 1996.
Endeavour will carry into orbit a six member crew. The crew of mission STS-77 are: Commander John Casper; Pilot Curt Brown; and Mission Specialists Andy Thomas, Dan Bursch, Mario Runco and Marc Garneau of the Canadian Space Agency.
The STS-77 crew are scheduled to arrive at KSC at about 9 a.m. Thursday, May 16. Their activities at KSC prior to launch will 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 p.m.)
- Clear launch pad of all non-essential personnel
- Perform test of the vehicle's pyrotechnic initiator controllers
Resume countdown (midnight)
Enter four-hour built-in hold at T-19 hours (8 a.m.)
- Resume orbiter and ground support equipment close-outs
- Demate orbiter mid-body umbilical unit and retract into fixed
service structure
Resume countdown (noon)
- Start final preparations of the Shuttle's three main engines for
main propellant tanking and flight
- Activate the orbiter’s flight controls and navigation systems
- Install mission specialists' seats in crew cabin
- Close-out the tail service masts on the mobile launcher platform
Enter planned hold at T-11 hours for 20 hours, 10 minutes (8 p.m.)
Resume countdown (4:10 p.m.)
- Continue installation of time critical flight crew equipment
- Perform pre-ingress switch list
- Start fuel cell flow-through purge
- Activate the orbiter's fuel cells
- Configure communications at Mission Control, Houston, for launch
- Clear the blast danger area of all personnel
- Switch Endeavour's purge air to gaseous nitrogen
Enter planned one-hour built-in hold at the T-6 hour mark (9:10 p.m.)
- Launch team verifies no violations of launch commit criteria prior
to cryogenic loading of the external tank
- Clear pad of all personnel
- Begin loading the external tank with about 500,000 gallons of
cryogenic propellants (about 9:40 p.m.)
Resume countdown (10:10 p.m.)
Enter two-hour hold at T-3 hours (1:10 a.m.)
- Close-out crew and Final Inspection Team proceed to Launch Pad 39B
Resume countdown at T-3 hours (3:10 a.m.)
- Crew departs Operations and Checkout Building for the pad (about 3:10 a.m.)
- Complete close-out preparations in the white room
- Check cockpit switch configurations
- Flight crew begins entry into the orbiter (about 3:40 a.m.)
- Astronauts perform air-to-ground voice checks with Launch Control
and Mission Control
- Close Endeavour's crew hatch (about 5 a.m.)
- 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 hold at T-20 minutes (5:50 a.m.)
- NASA Test Director conducts final launch team briefings
Resume countdown (6 a.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 10-minute hold at T-9 minutes (6:11 a.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 (6:21 a.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)
- SRB gimbal profile (T-0:21 seconds)
- Ignition of three Space Shuttle main engines (T-6.6 seconds)
- SRB ignition and liftoff (T-0)
T-TIME LENGTH OF HOLD HOLD BEGINS HOLD ENDS T-27 hours 4 hours 8:00 p.m. Thurs. 12:00 midnight Thurs. T-19 hours 4 hours 8:00 a.m. Fri. 12:00 noon Fri. T-11 hours 20 hours, 10 minutes 8:00 p.m. Fri. 4:10 p.m. Sat. T-6 hours 1 hour 9:10 p.m. Sat. 10:10 p.m. Sat. T-3 hours 2 hours 1:10 a.m. Sun. 3:10 a.m. Sun. T-20 minutes 10 minutes 5:50 a.m. Sun. 6:00 a.m. Sun. T-9 minutes 10 minutes 6:11 a.m. Sun. 6:21 a.m. Sun.
Commander (CDR): John Casper Pilot (PLT): Curt Brown Mission Specialist (MS1): Andy Thomas Mission Specialist (MS2): Dan Bursch Mission Specialist (MS3): Mario Runco Mission Specialist (MS4): Marc Garneau (CSA)
Sunday, May 19 1:30 a.m. Wake up * 2:00 a.m. Breakfast and Crew Photo 2:30 a.m. Weather briefing (CDR, PLT, MS2) 2:30 a.m. Don launch and entry suits (MS1, MS3, MS4) 2:40 a.m. Don launch and entry suits (CDR, PLT, MS2) * 2:55 a.m. Crew suiting photo * 3:10 a.m. Depart for launch pad 39B * 3:40 a.m. Arrive at white room and begin ingress * 5:00 a.m. Close crew hatch * 6:30 a.m. Launch * Televised events (times may vary slightly) All times Eastern
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