August 25, 1995

KSC Release No. 84-95

SPACE SHUTTLE MISSION STS-69 LAUNCH COUNTDOWN TO BEGIN MONDAY

	The countdown for launch of the Space Shuttle Endeavour on
mission STS-69 is scheduled to begin Monday, Aug. 28 at 3 p.m. EDT,
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 25 hours and 4 minutes of built-in
hold time leading to the opening of the launch window at 11:04 a.m.
(EDT) on Aug. 31. The launch window extends for 2 1/2 hours.

	STS-69 is the fifth Space Shuttle mission for 1995. It will
be the 9th flight of the Shuttle Endeavour and the 71st flight
overall in NASA’s Space Shuttle program.

	The primary purpose of mission STS-69 is to deploy and
retrieve the Wake Shield Facility-2 and the Spartan-201-03
free-flying payloads and to perform a spacewalk to practice for space
station activities.

	Endeavour was rolled out of Orbiter Processing Facility bay 1
on June 28 and mated with the external tank and solid rocket boosters
in the Vehicle Assembly Building. The Shuttle stack was then
transported to Pad 39-A on July 5. Endeavour was returned to the VAB
on August 1 as Hurricane Erin approached the east coast of Florida.
Endeavour was rolled back out to Pad 39-A a week later on Aug. 8.
Endeavour last flew in March of this year on mission STS-67.

	Also, launch was delayed for about four weeks as engineers
performed repair work on the solid rocket booster nozzles at the pad.
Insulation material around the joints in the nozzles had to be
removed and reinstalled using a different technique that prevents air
voids from forming in the material. These voids were responsible for
hot gas paths to the joints’ O-ring seals in two previous Shuttle
launches.

	The STS-69 crew are: Commander David Walker, Pilot Ken
Cockrell, and Mission Specialists James Voss, James Newman and
Michael Gernhardt.

	The crew is scheduled to arrive at KSC at about 12:30 p.m.
Monday, Aug. 28. Their activities at KSC prior to launch will include
equipment fit checks, medical examinations and opportunities to fly
in the Shuttle Training Aircraft.


COUNTDOWN MILESTONES

Launch - 3 Days (Monday, Aug. 28)

* Prepare for the start of the STS-69 launch countdown
* Perform the call-to-stations. All Firing Room console operators
  report on station.
* 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 3 p.m. EDT at the T-43 hour mark
* Start preparations for servicing fuel cell storage tanks
* Begin final vehicle and facility close-outs for launch
* Begin stowage of flight crew equipment

Launch - 2 Days (Tuesday, Aug. 29)

* Load backup flight system software into Endeavour's general purpose
  computers
* Check out back-up flight systems
* Inspect the orbiter's mid-deck and flight-deck and remove crew
  module platforms
* Review flight software stored in mass memory units and display systems

Enter first planned built-in hold at T-27 hours for duration of four
hours (7 a.m.)

* Clear launch pad of all personnel
* Perform test of the vehicle's pyrotechnic initiator controllers

Resume countdown (11 a.m.)

* Begin the 8-hour operation to load cryogenic reactants into
  Endeavour's fuel cell storage tanks

Enter four-hour built-in hold at T-19 hours (7 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

Resume countdown (11 p.m.)

* Demate orbiter mid-body umbilical unit and retract into fixed
  service structure
* Start final preparations of the Shuttle's three main engines for
  main propellant tanking and flight

Launch - 1 Day (Wednesday, Aug. 30)

* Activate flight controls and navigation systems
* Close-out the tail service masts on the mobile launcher platform

Enter planned hold at T-11 hours for 13 hours, 44 minutes (7 a.m.)

* 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
* Fill pad sound suppression system water tank
* Safety personnel conduct debris walkdown
* Move Rotating Service Structure (RSS) to the park position at about
  2:30 p.m.
* Following the RSS move, begin final stowage of mid-deck experiments
  and flight crew equipment

Resume countdown (8:44 p.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
* Clear the blast danger area of all non-essential personnel
* Switch Endeavour's purge air to gaseous nitrogen

Launch Day (Thursday, Aug. 31)

Enter planned one-hour built-in hold at the T-6 hour mark (1:44 a.m.)

* Launch team verifies no violations of launch commit criteria prior
  to cryogenic loading of the external tank
* Clear pad of all personnel

Resume countdown (2:44 a.m.)

* Begin loading the external tank with cryogenic propellants (2:44 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 (5:44 a.m.)

Enter two-hour hold at T-3 hours (5:44 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 proceeds to Launch Pad 39-A

Resume countdown at T-3 hours (7:44 a.m.)

* Crew departs Operations and Checkout Building for pad 39-A (7:49 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 Endeavour'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 hold at T-20 minutes (10:24 a.m.)

* NASA Test Director conducts final launch team briefings

Resume countdown (10:34 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 final 10-minute hold at T-9 minutes (10:45 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 (10:55 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 MPS 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-69

T-TIME       LENGTH OF HOLD             HOLD BEGINS          HOLD ENDS
T-27 hours     4 hours	             7:00 a.m. Tuesday	 11:00 a.m. Tuesday
T-19 hours     4 hours	             7:00 p.m. Tuesday	 11:00 p.m. Tuesday
T-11 hours    13 hours, 44 minutes   7:00 a.m. Wednesday  8:44 p.m. Wednesday
T-6  hours     1 hour	             1:44 a.m. Thursday	  2:44 a.m. Thursday
T-3  hours     2 hours	             5:44 a.m. Thursday	  7:44 a.m. Thursday
T-20 minutes  10 minutes	    10:24 a.m. Thursday	 10:34 a.m. Thursday
T-9  minutes  10 minutes	    10:45 a.m. Thursday	 10:55 a.m. Thursday


CREW FOR MISSION STS-69

David Walker	    Commander (CDR)
Ken Cockrell	    Pilot (PLT)
James Voss	    Mission Specialist (MS1)
James Newman	    Mission Specialist (MS2)
Michael Gernhardt   Mission Specialist (MS3)


SUMMARY OF STS-69 LAUNCH DAY CREW ACTIVITIES

Thursday, Aug. 31

   3:00 a.m.	Wake up
   3:30 a.m.	Breakfast
   4:00 a.m.	Free Time
*  6:39 a.m.	Crew Photo and Snack
   7:09 a.m.	Weather briefing (CDR, PLT, MS2)
   7:09 a.m.	Don flight equipment (MS1, MS3)
   7:19 a.m.	Don flight equipment (CDR, PLT, MS2)
*  7:30 a.m.	Crew suiting photo
*  7:49 a.m.	Depart for launch pad 39A
*  8:19 a.m.	Arrive at white room and begin ingress
*  9:34 a.m.	Close crew hatch
* 11:04 a.m.	Launch

* Televised events -- times may vary