51-C (15)

DISCOVERY (3)

Pad 39-A (27)

15th Shuttle mission

3rd Flight OV-103

4th KSC landing

Crew:

Thomas K. Mattingly II (3), Commander

Loren J. Shriver (1), Pilot

Ellison S. Onizuka (1), Mission Specialist 1

James F. Buchli (1), Mission Specialist 2

Gary E. Payton (1), Payload Specialist 1

Milestones:

OPF - Nov. 16,1984

VAB - Dec. 21, 1984

PAD - Jan. 5,1985

Payload:

DoD 85-1

Mission Objectives:

Click here for Additional Info on 51-C

Because of the security classification assigned to this mission, this report contains no discussion of any of the mission activities or accomplishments.

Launch:

January 24, 1985, 2:50:00 p.m. EST. Launch Jan. 23 scrubbed due to freezing weather conditions. (Orbiter Challenger scheduled for Mission 51-C, but thermal tile problems forced substitution of Discovery.) Launch Weight: 250,891 lbs

The countdown phase was completed satisfactorily, however, two minor Orbiter problems were noted during that period. The first occurred during the T-3 hour hold and involved a force fight in the right inboard elevon actuator between channel 4 and channels 1, 2, and 3. The condition corrected itself within 22 seconds after APU (auxiliary power unit) start up at T-5 minutes. A similar problem with the same channels in the same actuator occurred on STS 41-D (first flight of this vehicle).

The second problem that was noted during the countdown phase was the high helium concentration in the Orbiter mid-body. A pressure decay test showed no significant system leakage. The high helium concentration disappeared when the MPS (main propulsion system) gaseous helium system was pressurized to the flight level.

System operations were all nominal during the scent phase. SRB motor performance was near the predicted levels and well within the allowed envelopes. External tank and MPS performance was excellent with MECO (main engine cutoff) near the predicted time.

At external tank separation, the BFS (backup flight system) did not automatically proceed to major mode 104. The crew performed the necessary manual procedures, and the BFS operated satisfactorily until the deorbit maneuver when the BFS time for deorbit maneuver ignition was 8 seconds late. However, the BFS operated satisfactorily for entry.

Orbit:

Altitude: 220nm

Inclination: 28.5 degrees

Orbits: 49

Duration: 3 days, 1 hour, 33 minutes, 23 seconds.

Distance: 1,250,000 miles

Hardware:

SRB: BI-015

SRM: 015LW(HPM)

ET : 14/LWT-7

MLP : 1

SSME-1: SN-2109

SSME-2: SN-2018

SSME-3: SN-2012

Landing:

January 27, 1985, 4:23:23 p.m. EST (027:21:23:23 GMT), Runway 15, Kennedy Space Center, Fla. Rollout distance: 7,352 feet. Rollout time: 50 seconds. Landing Weight: classified.

Mission Highlights:

First mission dedicated to Department of Defense. U.S. Air Force Inertial Upper Stage (IUS) booster deployed and met mission objectives.

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