STS-38 MISSION SUMMARY – Launch Phase
The STS-38 mission was launched at 319:23:48:15.006 GMT (6:48:15 p.m. EST on November 15, 1990) from Launch Pad 39A on a Department of Defense mission. The launch phase was satisfactory in all respects and all orbiter subsystems operated in a nominal manner. All SSME and RSRM start sequences occurred as expected. First stage ascent performance was normal with SRB separation, entry, deceleration, and water impact occurring as planned. Performance of the SSMEs, ET, and MPS was also normal. The OMS-1 and OMS-2 maneuvers were performed with nominal results.
Two SRB in-flight anomalies were identified: (a) Photographic analysis identified debris exiting from the thermal curtain region on both SRBs during ascent. (b) the forward face of the right SRB/ET attachment ring had two areas where Instafoam was missing. ET flight performance was excellent. The ET tumble system was inactive on this flight. Radar data from Bermuda and Antigua confirmed that the ET did not tumble. The ET entry and rupture/breakup data are not available, but ET entry and breakup was within the expected footprint.
Ascent MPS performance appeared to be completely normal. The step 2 gaseous oxygen fixed-orifice flow control valve was flown for the first time on STS-38. Postflight analysis of the valve performance data reveals good agreement with predicted performance. Data indicate that the liquid oxygen and liquid hydrogen pressurization systems performed properly, and that all net positive suction pressure requirements were met throughout the flight.
The speed indicator on the engine 1 liquid hydrogen recirculation pump had failed during a previous STS-38 tanking test and was not operative for this launch. Alternative critical measurements were used to ensure that the pump was operating properly.
After SSME shutdown, approximately four minutes after main engine cutoff, an anomaly was recorded on main engine 1. The indicated failure was the main engine 1 POGO charge transducer, and its failure did not impact the mission. Engine dynamic data generally compared well with previous flight and test data. All on-orbit activities associated with the SSMEs were accomplished successfully. No other significant flight problems were identified.
While operating on A controller, Water Spray Boiler WSB 2 failed to cool the Auxiliary Power Unit lubrication oil during ascent. WSB 2 was switched to the B controller and APU2 was left on after APUs 1 and 3 were left shut down to allow evaluation of lubrication oil cooling on the B controller. Effective lubrication oil cooling was achieved one minute six seconds after the switch to the B controller; APU 2 was then shut down. The A controller was used for entry and data showed nominal operation.
Two Development Test Objectives were completed during ascent: DTO 301 – Ascent Structural Capability Evaluation – The objective of DTO 301 was to verify the adequacy of the shuttle structural capability at (or near) design conditions; DTO 309 – Ascent Flutter Boundary Evaluation (Test 4) – The objective of DTO 309 was to verify shuttle performance near the ascent flutter boundary.
On launch day, 25 video films of ascent were screened. A potential anomaly was observed when a piece of ice fell from the liquid hydrogen umbilical plate and hit the edge of the umbilical cavity. A review by the subsystem manager indicated that no damage had been done, and that no anomaly had occurred. Subsequent postflight investigation also showed no damage. The results of the entire launch film review revealed no unexpected events or occurrences.
(STS-38 Space Shuttle Mission Report, NSTS-08308, January 1991 – edited)