SHUTTLE MISSION STS-89 LAUNCH COUNTDOWN BEGINS TODAY

NASA will begin the countdown for launch of Space Shuttle Endeavour on mission STS-89 today at 7 p.m. EST at the T-43 hour mark. The KSC launch team will conduct the countdown from Firing Room 1 of the Launch Control Center.

The countdown includes 31 hours and 42 minutes of built-in hold time leading to an opening of the launch window at about 9:42 p.m. on Jan. 22. The launch window extends for 10 minutes though the preferred launch time is about 9:48 p.m.

STS-89 is the first Space Shuttle mission of 1998, the 12th flight of the orbiter Endeavour and the 89th flight overall in NASA's Space Shuttle program. STS-89 is scheduled to last 8 days, 19 hours, and 48 minutes with a planned KSC landing at 5:36 p.m. on Jan. 31.

Endeavour was rolled out of Kennedy Space Center's Orbiter Processing Facility bay 1 on Dec. 12, 1997, and mated with the external tank and solid rocket boosters in the Vehicle Assembly Building. The Shuttle stack was transported to Pad 39A on Dec. 19.

Carrying a seven member crew, mission STS-89 is Endeavour's first flight to Russia's space station Mir. This will be NASA's 8th of nine missions to dock with Mir. All previous missions to dock with Mir were aboard the orbiter Atlantis.

This flight transports the final U.S. astronaut slated to stay aboard the space station for an extended period of time. Mission Specialist Andy Thomas will conclude Phase 1 of the International Space Station with a four-month stay on Mir. He will replace Dr. Dave Wolf who arrived there in September 1997. Wolf will return to Earth with the Endeavour crew and Thomas will remain at the space outpost through May.

During the five days Endeavour is docked with Mir, the crew will exchange several tons of scientific and logistical equipment and supplies, including water. They will also conduct several scientific experiments over the course of the mission.

The STS-89 crew consist of: Commander Terrence Wilcutt, Pilot Joe F. Edwards, Mission Specialists Andrew Thomas, Bonnie Dunbar, James Reilly, Michael Anderson, and Salizhan Sharipov.

The crew is scheduled to arrive at KSC at about 2:30 p.m. today. Their activities at KSC prior to launch will include crew equipment fit checks, medical examinations and opportunities to fly in the Shuttle Training Aircraft.

• Prepare for the start of the STS-89 launch countdown
• Perform the call-to-stations (6:30 p.m.)
• All members of the launch team report to their respective consoles in Firing Room 1 in the Launch Control Center for the start of the countdown
• Countdown begins at the T-43 hour mark (7 p.m.)
• Begin final vehicle and facility close-outs for launch
• Check out back-up flight systems
• Review flight software stored in mass memory units and display systems
• Load backup flight system software into Endeavour's general purpose computers
• Begin stowage of flight crew equipment

• Remove mid-deck and flight-deck platforms
• Activate and test navigational systems
• Complete preparations for loading of power reactant storage and distribution system
• Mid-deck and flight deck preliminary inspections complete

Enter first planned built-in hold at T-27 hours for duration of four hours (11 a. m.)

• Clear launch pad of all non-essential personnel
• Perform test of the vehicle's pyrotechnic initiator controllers

Resume countdown (3 p.m.)

• Begin operations to load cryogenic reactants into Endeavour's fuel cell storage tanks (3-11 p.m.)

Enter eight-hour built-in hold at T-19 hours (11 p.m.)

• After cryogenic loading operations, re-open the pad
• Demate orbiter mid-body umbilical unit and retract into fixed service structure
• Resume orbiter and ground support equipment close-outs

Resume countdown (7 a.m.)

• Start final preparations of the Shuttle's three main engines for main propellant tanking and flight
• Install mission specialists' seats in crew cabin
• Fill pad sound suppression system water tank
• Close-out the tail service masts on the mobile launcher platform

Enter planned hold at T-11 hours for 14 hours, 52 minutes (3 p.m.)

• Activate the orbiter's flight controls and navigation systems
• Begin startracker functional checks
• Activate orbiter's inertial measurement units
• Install film in numerous cameras on the launch pad
• Perform orbiter ascent switch list in crew cabin
• Activate the orbiter's communications systems
• Safety personnel conduct debris walk down
• Flight crew equipment late stow

• Move Rotating Service Structure (RSS) to the park position (4 a.m.)
• Perform ascent switch list

Resume countdown (5:52 a.m.)

• Start fuel cell flow-through purge
• Activate the orbiter's fuel cells
• Clear the blast danger area of all non-essential personnel
• Configure communications at Mission Control, Houston, for launch
• Switch Endeavour's purge air to gaseous nitrogen
• Complete inertial measurement unit activation

Enter planned two-hour built-in hold at the T-6 hour mark (10:52 a.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 12:32 p.m.)

Resume countdown (12:52 p.m.)

• Complete filling the external tank with its flight load of liquid hydrogen and liquid oxygen propellants (about 3:32 p.m.)

Enter planned two-hour built-in hold at T-3 hours (3:52 p.m.)

• Perform inertial measurement unit preflight calibration
• Align Merritt Island Launch Area (MILA) tracking antennas
• 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 39A

Resume countdown at T-3 hours (5:52 p.m.)

• Crew departs Operations and Checkout Building for the pad (about 5:58 p.m.)
• Complete close-out preparations in the white room
• Check cockpit switch configurations
• Flight crew begins entry into the orbiter (about 6:28 p.m.)
• Astronauts perform air-to-ground voice checks with Launch Control and Mission Control
• Close Endeavour's crew hatch (about 7:43 p.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 (8:32 p.m.)

• NASA Test Director conducts final launch team briefings
• Complete inertial measurement unit pre-flight alignments

Resume countdown (8:42 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 planned 46-minute (estimated) hold at T-9 minutes (8:53 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 (about 9:39 p.m.)

• Start automatic ground launch sequencer (T-9 minutes)
• Retract orbiter crew access arm (T-7:30)
• Start mission recorders (T-6:15)
• Start Auxiliary Power Units (T-5)
• Arm SRB and ET range safety safe and arm devices (T-5)
• 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 minute)
• 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)