January 27, 1995

KSC Release No. 6-95

SPACE SHUTTLE MISSION STS-63 LAUNCH COUNTDOWN TO BEGIN SUNDAY

     The countdown for launch of the Space Shuttle Discovery on
mission STS-63 is scheduled to begin Sunday, Jan. 29 at 4:30 p.m.
EST, at the T-43 hour mark.

     The countdown includes 37 hours and 15 minutes of built-in
hold time leading to the opening of the launch window at
approximately 12:48 a.m. (EST) on Feb. 2. The launch window
extends for 5 minutes. The exact time of launch will be
determined about 90 minutes before liftoff based on the location
of the Mir space station.

     The launch of Discovery will mark the beginning of the first
mission to Russia's space station Mir. A rendezvous with the
space station is scheduled for day four of the flight. Though
Discovery will only come within about 38 feet of the station,
this flight will set the stage for seven planned docking missions
between the orbiter and Mir, the first of which is currently
scheduled for early this summer.

     In order to accommodate the short five minute window
necessary to rendezvous with Mir, several changes have been made
to the launch countdown. Most significant is the addition of an
extra 30 minutes built into the hold at T-9 minutes.

     STS-63 is the first of eight missions now scheduled for
1995. This will be the 20th flight of the Shuttle Discovery and
the 67th flight overall in NASA's Space Shuttle program.

     The primary payloads of mission STS-63 is the SPARTAN-204
free-flyer and Spacehab-3. SPARTAN (Shuttle Pointed Autonomous
Research Tool for Astronomy) will be deployed on flight day 5 and
retrieved 48 hours later for return to Earth. SPARTAN consists of
instruments for celestial observations.

     Also located in the payload bay is the Orbital Debris Radar
Calibration Sphere-2 (ODERACS-2) experiment, in which calibration
targets ranging from two to six inches in diameter will be
ejected from the payload bay and tracked by ground-based radar
and telescopes.

     Discovery was rolled out of Orbiter Processing Facility bay
2 on Jan. 5 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 Jan. 10. Discovery last flew in
September 1994.

     The STS-63 crew are: Commander James Wetherbee, Pilot Eileen
Collins, Mission Specialists Bernard Harris, Michael Foale and
Janice Voss; and Russian cosmonaut Vladimir Titov.

     Collins will be the first female to pilot a Space Shuttle
flight.

     The crew is scheduled to arrive at KSC at about 12 midnight
Sunday evening, Jan. 29. Their activities at KSC prior to launch
will include equipment fit checks, medical examinations and
opportunities to fly in the Shuttle Training Aircraft.

     As the countdown begins, the KSC launch team in Firing Room
3 of the Launch Control Center will verify all systems to assure
the Shuttle is properly powered up and the data processing and
backup flight control systems are operating trouble free.

     Verifications conducted throughout the launch countdown
ensure continuous reviews are made of the flight software stored
in the orbiter's twin memory banks. Computer controlled display
systems will be activated and the backup flight system general
purpose computer will be loaded.

     Operations will also begin to prepare the orbiter for on-
board cryogenic loading. Later, orbiter navigation aids will be
turned on and tested and the inertial measurement units
activated. Ground crews will make the final storage of mid-deck
and flight deck supplies, perform microbial samplings of the
flight crew's drinking water and check water levels in the waste
management system.

     At T-27 hours, the countdown enters its first scheduled
hold. This is a four-hour hold lasting from 8:30 a.m. to 12:30
p.m. Monday.

     When the countdown resumes, the launch pad will be cleared
of all personnel for loading cryogenic reactants into the power
reactant storage and distribution system tanks located under the
payload bay lining. The reactants are used by the orbiter's fuel
cells to provide electricity to the orbiter and drinking water
for the crew. Cryogenic flow operations are scheduled to start at
about 12:30 p.m. Monday and continue for about 7 hours.

     As servicing of the cryogenic tanks is completed, the clock
will enter an eight-hour built-in hold at the T-19 hour mark.
This hold will last from 8:30 p.m. Monday to 4:30 a.m. Tuesday.

     Following cryogenic loading operations, the pad will be re-
opened for scheduled pre-launch activities. The orbiter mid-body
umbilical unit, used to load the super-cold reactants in the
orbiter's fuel cell tanks, will be demated and retracted into the
launch structure.

     When the countdown resumes, technicians will complete final
vehicle and facility close-outs and begin configuring Discovery's
cockpit for flight. The orbiter's flight control system and
navigation aids will be activated. The stowable crew seats will
be installed in the flight and mid-decks.

     The countdown will enter another built-in hold at the T-11
hour mark at 12:30 p.m. Tuesday. This 20-hour, 25-minute hold
will last until 8:55 a.m. Wednesday. During this hold, time
critical equipment will be installed in the orbiter's cockpit.
The inertial measurement units and the orbiter's communications
systems will be activated.

     At about 8 a.m. Wednesday, the Rotating Service Structure is
scheduled to be moved away from the vehicle and placed in launch
position.

     At T-9 hours (10:55 a.m. Wednesday) the onboard fuel cells
will be activated. At T-8 hours, the launch team will evacuate
the blast danger area and clear the pad for loading the external
tank with the cryogenic propellants for the orbiter's main
engines. At T-7 hours, 30 minutes, conditioned air that is
flowing through the orbiter's payload bay and other areas on the
orbiter will be switched to gaseous nitrogen in preparation for
fueling the external tank. The inertial measurement units will
transition from the warm-up stage to the operate/attitude
determination mode at T-6 hours, 45 minutes.

     The countdown will enter another planned built-in hold at
the T-6 hour mark at 1:55 p.m. Wednesday. During this two-hour
hold, final preparations for loading the external tank will be
completed. Also, a pre-tanking weather briefing will be conducted
for the benefit of the Mission Management Team prior to their
giving approval to begin tanking operations.

     Chilldown of the lines that carry the cryogenic propellants
to the external tank begins when the clock starts counting again
at 3:55 p.m. Wednesday. Filling and topping off the external tank
should be complete about three hours later at the beginning of
the next planned hold at T-3 hours, or 6:55 p.m. Wednesday.

     During the two-hour hold at the T-3 hour mark, the Final
Inspection Team (formerly known as the Ice and Debris Inspection
Team) will conduct a final survey of the pad and various Shuttle
components ensuring their readiness for flight. Also, the close-
out crew will be dispatched to the pad and begin configuring the
crew module and white room for the flight crew's arrival. Liquid
oxygen and liquid hydrogen will be in a stable replenish mode
during this time to replace any propellant that "boils" off.

     The six flight crew members will be awakened at about 7:30
p.m. Wednesday and seated for their final meal before launch at
about 8 p.m. Following their meal, the crew will receive a
briefing on weather conditions at KSC and at the TransAtlantic
Abort Landing sites.

     The flight crew will suit-up in their partial-pressure
suits, then leave the Operations and Checkout Building at about 9
p.m. Wednesday. They will arrive at the Pad 39B white room at
about 9:30 p.m. where they will be assisted into the crew cabin
by white room personnel.

     Just prior to the T-60 minute mark, the test team and the
flight crew will get another weather update, including
observations from astronaut Robert Cabana flying in a Shuttle
Training Aircraft in the KSC area.

     The next built-in hold occurs at the T-20 minute mark (11:35
p.m. Wednesday) and lasts for 10 minutes. The final build-in hold
occurs at the T-9 minute mark (11:56 p.m.) This hold usually
extends for 10 minutes, however, due to the short 5 minute launch
window necessary to rendezvous with Mir, the planned hold has
been extended to 40 minutes. Based on the Mir orbit, the exact
launch time will be adjust and the hold will be extended or
shortened as necessary. This adjustment will not be more than a
few minutes. During the final hold at T-9 minutes, the flight
crew and ground team receive the NASA launch director's and the
mission management team's final "go" for launch.

     Milestones after the T-9 minute mark include start of the
ground launch sequencer; retraction of the orbiter access arm at
T-7 minutes, 30 seconds; start of the orbiter's auxiliary power
units at T-5 minutes; pressurization of the liquid oxygen tank
inside the external tank at T-2 minutes, 55 seconds;
pressurization of the liquid hydrogen tank at T-1 minute, 57
seconds; ground power disconnection from the orbiter at T-50
seconds; and the electronic "go" to Discovery's onboard computers
to start their own terminal countdown sequence at T-31 seconds.
The orbiter's three main engines will start at T-6.6 seconds.

(The countdown will target launch for 12:45 a.m., the earliest
possible launch opportunity based on the Mir orbit. The exact
launch time will be adjusted at the T-9 minute hold.)

                      COUNTDOWN MILESTONES

                Launch - 4 Days (Sunday, Jan. 29)

Prepare for the start of the STS-63 launch countdown
Perform the call-to-stations at the T-43 hour mark
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 4:30 p.m. EST


                Launch - 3 Days (Monday, Jan. 30)

Start preparations for servicing fuel cell storage tanks
Begin final vehicle and facility close-outs for launch

Enter first planned built-in hold at T-27 hours for duration of
four hours (8:30 a.m.)

Check out back-up flight systems
Review flight software stored in mass memory units and display systems
Load backup flight system software into Discovery's general
  purpose computers
Begin stowage of flight crew equipment
Inspect the orbiter's mid-deck and flight-deck and remove
  crew module platforms
Perform test of the vehicle's pyrotechnic initiator controllers

Resume countdown (12:30 p.m.)

Clear launch pad of all personnel
Begin the 7 hour operation to load cryogenic reactants into
  Discovery's fuel cell storage tanks

Enter eight-hour built-in hold at T-19 hours (8:30 p.m.)

After cryogenic loading operations, re-open the pad
Resume orbiter and ground support equipment close-outs


               Launch - 2 Days (Tuesday, Jan. 31)

Demate orbiter mid-body umbilical unit and retract into
  fixed service structure

Resume countdown (4:30 a.m.)

Start final preparations of the Shuttle's main engines for
  main propellant tanking and flight
Activate 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, 25 minutes (12:30 p.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
Power on Spacehab laboratory module and begin experiment stowage

                Launch -1 Day (Wednesday, Feb. 1)

Safety personnel conduct debris walkdown
Move Rotating Service Structure (RSS) to the park position
  at about 8 a.m.
Following the RSS move, begin final stowage of mid-deck
  experiments and flight crew equipment

Resume countdown (8:55 a.m.)

Install 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 Discovery's purge air to gaseous nitrogen

Enter planned two-hour built-in hold at the T-6 hour mark (1:55 p.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 (3:55 p.m.)

Begin loading the external tank with cryogenic propellants (3:55 p.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 (6:55 p.m.)

Enter two-hour hold at T-3 hours (6:55 p.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 39B

Resume countdown at T-3 hours (8:55 p.m.)

Crew departs Operations and Checkout Building for the pad at 9 p.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 Discovery'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
Final launch time determined based on Mir location

Enter planned 10-minute hold at T-20 minutes (11:35 p.m.)

NASA Test Director conducts final launch team briefings

Resume countdown (11:45 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 hold at T-9 minutes. Hold will last for about 40 minutes.
  (11:37 a.m.)

Launch Director, Mission Management Team and NASA Test
  Director conduct final polls for go/no go to launch

                  Launch Day (Thursday, Feb. 2)
                                
Resume countdown at T-9 minutes (12:36 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)
LPS go for start of orbiter automatic sequence (T-0:31 seconds)
Ignition of Shuttle's three main engines (T-6.6 seconds)
SRB ignition and liftoff (T-0)

              SUMMARY OF BUILT-IN HOLDS FOR STS-63

T-TIME ---------- LENGTH OF HOLD -------- HOLD BEGINS ------HOLD ENDS

T-27 hours ---------4 hours --------------8:30 a.m.Mon.----12:30 p.m. Mon.
T-19 hours ---------8 hours --------------8:30 p.m.Mon.-----4:30 a.m. Tues.
T-11 hours --------20 hrs.,25 mins.------12:30 p.m.Tues.----8:55 a.m. Wed.
T-6 hours ----------2 hours --------------1:55 p.m.Wed.-----3:55 p.m. Wed.
T-3 hours ----------2 hours --------------6:55 p.m.Wed.-----8:55 p.m. Wed.
T-20 minutes ------10 minutes -----------11:35 p.m.Wed.----11:45 p.m. Wed.
T-9 minutes -------40 minutes -----------11:56 p.m.Wed.----12:36 a.m. Thurs.


                     CREW FOR MISSION STS-63

Commander (CDR): James Wetherbee
Pilot (PLT): Eileen Collins
Mission Specialist (MS1): Bernard Harris
Mission Specialist (MS2): Michael Foale
Mission Specialist (MS3): Janice Voss
Mission Specialist (MS4): Vladimir Titov


          SUMMARY OF STS-63 LAUNCH DAY CREW ACTIVITIES

Wednesday, Feb. 1

 7:20 p.m. Wake up
 7:50 p.m. Breakfast and crew photo
 8:20 p.m. Weather briefing (CDR, PLT, MS2)
 8:20 p.m. Don flight equipment (MS1, MS3, MS4)
 8:30 p.m. Don flight equipment (CDR, PLT, MS2)
 9:00 p.m. Depart for launch pad 39B
 9:30 p.m. Arrive at white room and begin ingress
10:45 p.m. Close crew hatch

Thursday, Feb. 2, 1995

12:48 a.m. Launch (time estimated)