SPACE SHUTTLE MISSION STS-84 LAUNCH COUNTDOWN TO BEGIN MAY 11

NASA will begin the countdown for launch of Space Shuttle Atlantis on the sixth mission to dock with Russia's space station Mir on May 11 at 11 p.m. at the T-43 hour mark. The KSC launch team will conduct the countdown from Firing Room 3 of the Launch Control Center.

The countdown includes 34 hours and seven minutes of built-in hold time leading to the opening of the launch window at about 4:07 a.m. (EDT) on May 15. The launch window extends for about 7 minutes. The exact time of launch will be determined about 90 minutes before liftoff based on the location of the Mir space station.

In order to accommodate the short window necessary to rendezvous and dock with Mir, some changes have been made to the standard launch countdown. Most significant is the addition of an extra 30 minutes to the normal 10 minute built-in hold at T-9 minutes. Tanking is scheduled to begin at about 6:15 p.m. Wednesday, May 14.

STS-84 is the fourth Space Shuttle mission of 1997. This will be the 19th flight of the orbiter Atlantis and the 84th flight overall in NASA's Space Shuttle program. Atlantis last flew on the fifth Shuttle/Mir docking flight in January.

Atlantis rolled out of Kennedy Space Center's Orbiter Processing Facility bay 3 on April 19 and was mated with the external tank and solid rocket boosters in the Vehicle Assembly Building. The Shuttle stack was then transported to Pad 39A on April 24. The vehicle was processed for flight without any significant or unexpected technical difficulties.

On mission STS-84, Atlantis will carry into orbit a seven member crew. Mission Specialist Michael Foale will replace Jerry Linenger on the Mir space station. Linenger will return to Earth with the rest of the STS-84 crew. Foale will remain on Mir until Atlantis again docks with the space station in September.

The STS-84 crew are: Commander Charles Precourt, Pilot Eileen Collins, and Mission Specialists Jean-Francois Clervoy, Carlos Noriega, Edward Lu, Elena Kondakova and Michael Foale.

The crew are scheduled to arrive at KSC at about 10:30 p.m., May 11. Their activities at KSC prior to launch will include equipment fit checks, medical examinations and opportunities to fly in the Shuttle Training Aircraft.

(The countdown will target launch for 4:07 a.m. on Thursday, May 15. The exact launch time will be adjusted at the T-9 minute hold.)

• Prepare for the start of the STS-84 launch countdown
• Perform the call-to-stations (10:30 p.m. Sunday, May 11)
• All members of the launch team report to their respective consoles in Firing Room 3 in the Launch Control Center for the start of the countdown.
• Countdown begins at the T-43 hour mark (11 p.m.)

• Start preparations for servicing fuel cell storage tanks
• 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 Atlantis' general purpose computers
• Begin stowage of flight crew equipment
• Inspect the orbiter's mid-deck and flight-deck and remove crew module platforms

Enter first planned built-in hold at T-27 hours for duration of four hours (3 p.m.)

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

Resume countdown (7 p.m.)

• Clear launch pad of all personnel
• Begin operations to load cryogenic reactants into Atlantis' fuel cell storage tanks (7 p.m. - 3 a.m.)

• After cryogenic loading operations, re-open the pad

Enter four-hour built-in hold at T-19 hours (3 a.m.)

• Resume orbiter and ground support equipment close-outs
• Demate orbiter mid-body umbilical unit and retract into fixed service structure

Resume countdown (7 a.m.)

• 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 21 hours, 17 minutes (3 p.m.)

• Install film in numerous cameras on the launch pad

• Perform orbiter ascent switch list in crew cabin
• Activate the orbiter's communications systems
• Activate orbiter's inertial measurement units
• Fill pad sound suppression system water tank
• Safety personnel conduct debris walkdown
• Move Rotating Service Structure (RSS) to the park position (10 a.m.)
• Following the RSS move, begin final stowage of mid-deck experiments and flight crew equipment

Resume countdown (12:17 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 non-essential personnel
• Switch Atlantis' purge air to gaseous nitrogen

Enter planned two-hour built-in hold at the T-6 hour mark (5:17 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 6:15 p.m.)

Resume countdown (7:17 p.m.)

• Complete filling the external tank with its flight load of liquid hydrogen and liquid oxygen propellants (about 9 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

Enter two-hour hold at T-3 hours (10:17 p.m.)

• Close-out crew and Final Inspection Team proceeds to Launch Pad 39A

Resume countdown at T-3 hours (12:17 a.m.)

• Crew departs Operations and Checkout Building for the pad (about 12:42 a.m.)
• Complete close-out preparations in the white room
• Check cockpit switch configurations
• Flight crew begins entry into the orbiter (about 1:12 a.m.)
• Astronauts perform air-to-ground voice checks with Launch Control and Mission Control
• Close Atlantis' crew hatch (about 2:27 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 (2:57 a.m.)

• NASA Test Director conducts final launch team briefings

Resume countdown (3:07 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 40-minute hold at T-9 minutes (3:18 a.m.)

(This is the last planned built-in hold. Other hold options are available if necessary. During this hold, the exact launch time will be determined based on the exact location of the Mir space station. The hold time could vary by as much as a minute or two.)

• 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 3:58 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)

         Commander (CDR):  Charles Precourt
             Pilot (PLT):  Eileen Collins
Mission Specialist (MS1):  Jean-Francois Clervoy
Mission Specialist (MS2):  Carlos Noriega
Mission Specialist (MS3):  Edward Lu
Mission Specialist (MS4):  Elena Kondakova
Mission Specialist (MS5):  Michael Foale (up)
Mission Specialist (MS6):  Jerry Linenger (down)

Wednesday, May 14

   6:00 p.m. 	Wake up
   6:35 p.m. 	Breakfast
* 11:32 p.m. 	Lunch and crew photo

Thursday, May 15

  12:02 a.m. 	Weather briefing (CDR, PLT, MS2)
  12:02 a.m.	Don launch and entry suits (MS1, MS3, MS4, MS5)
  12:12 a.m.	Don launch and entry suits (CDR, PLT, MS2)
* 12:30 a.m.	Crew suiting photo
* 12:42 a.m.	Depart for launch pad 39A
*  1:12 a.m.	Arrive at white room and begin ingress
*  2:27 a.m.	Close crew hatch
*  4:07 a.m.	Launch

*Televised events (times may vary slightly)
All times Eastern