Space Shuttle NASA Mission Reports: 1998 Missions, STS-89, STS-90, STS-91, STS-95, STS-88 by World Spaceflight News & National Aeronautics and Space Administration (NASA)

Author:World Spaceflight News & National Aeronautics and Space Administration (NASA)
Language: eng
Format: azw
Publisher: Progressive Management
Published: 2012-01-16T05:00:00+00:00

The payload bay doors operated properly during both the opening and closing operations. Dual motor run times were exhibited in both cases. The radiators were not deployed.

The tires, which exhibited ply undercutting only on the right-hand inboard tire, were described as being in average condition for a landing on the KSC SLF runway.

The ET/Orbiter separation devices (EO-1, EO-2 and EO-3) functioned normally. No ordnance fragments were found on the runway beneath the umbilical cavities. The EO-2 and EO-3 fitting retainer springs were in the normal configuration. No clips were missing from the "salad bowls". Also, virtually no umbilical closeout foam or white room temperature vulcanizing (RTV) material adhered to the umbilical plate near the LH2 recirculation line disconnect.

All drag chute hardware was recovered and appeared to have functioned normally. The two pyrotechnic devices on the reefing line cutters had been expended.

Integrated Vehicle Heating and Thermal Interfaces

The prelaunch thermal interface purges were normal with no problems noted. The ascent aerodynamic and plume heating was normal. The entry aerodynamic heating on the SSME nozzles was also normal.

Thermal Control Subsystem

The thermal control subsystem (TCS) performance during the STS-91 mission was nominal during all phases of the countdown and mission. All subsystem temperatures were maintained within acceptable limits. The overboard water flow from the fuel cell 3 water relief system nozzle did not adversely affect the mission.

Prior to the flight, the attitude time-line assessment of the docked phase indicated no potential Orbiter thermal constraints; however, one minor change to the docked attitude was made, and this change produced two degrees more sun below the wing plane. This slight change increased the sun on the main landing gear (MLG) and this provided a desirable increase in the temperature of the main landing gear. In addition, numerous changes in the attitude of the vehicle were made during the undocked portions of the flight to accommodate the AMS payload thermal requirements.

Aerothermodynamics

The boundary layer transition was asymmetrical and MADS data showed boundary layer transition from laminar to turbulent flow occurred early on the left wing at Mach 17.0. The fuselage transition to turbulent flow occurred at Mach 9.7 and 1139 seconds after entry interface. No data were available from the right wing; however, it is assumed to have occurred at the same Mach number as the fuselage. The aileron deflection history indicates that the asymmetrical at Mach 18, and jumped to symmetrical at Mach 9.5. The cause of the asymmetric transition is being evaluated. The overall vehicle acreage heating was normal for a heavy, high-inclination entry; however, the left wing experienced very high heating but all temperatures were within certification limits.

Local heating inspections were continuing as this report was written. The initial findings showed a 17 slumped tiles in various areas of the vehicle. Also there was a large number of charred filler bars on the left wing.

Thermal Protections Subsystem and Windows

The thermal protection subsystem (TPS) and windows performed nominally with no inflight anomalies identified. Entry heating was higher than normal based on structural temperature rise data, particularly in the wings where the rise was 18° F higher than previously observed on this vehicle.

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