STS-68 launch attempt report
mary-frances jagod
STS-68 LAUNCH ATTEMPT REPORT
AUGUST 18, 1994
GEORGE C. MARSHALL SPACE FLIGHT CENTER
Cynthia A. Snoddy
Chairman, MSFC Space Shuttle
Flight Evaluation Team
STS-65 MISSION DATA SUMMARY
PAYLOAD MANIFEST:
PAYLOAD BAY Space Radar Laboratory-2 (SRL-2),
Get Away Specials (5) (GAS)
MID-DECK Commercial Protein Crystal Growth (CPCG),
Chromosome and Plant Cell Division in Space Experiment
(CHROMEX),
Biological Research in Canister (BRIC),
Cosmic Radiation Effects and Activation Monitor (CREAM),
Military Applications of Ship Tracks (MAST)
INSTRUMENTATION: None
ON-PAD ABORT DATE: August 18, 1994
LAUNCH WINDOW: 5:54 am - 9:24 am CDT
ON-PAD ABORT TIME: 94:230:10:53:58.157 GMT
5:54 am CDT
NSTS DATABASE T-REF: 94:230:10:54:00.000
SSME#3 START TIME: 94:230:10:53:53.437
SSME#2 START TIME: 94:230:10:53:53.558
SSME#1 START TIME: 94:230:10:53:53.679
SSME#3 SHUTDOWN TIME: 94:230:10:53:58.157
SSME#2 SHUTDOWN TIME: 94:230:10:53:59.358
SSME#1 SHUTDOWN TIME: 94:230:10:54:00.638
LAUNCH SITE: KSC Pad 39A
MOBILE LAUNCH PLATFORM: MLP-1
ORBITAL INCLINATION: 57 degrees
ORBITAL ALTITUDE: 120 nautical miles
INSERTION MODE: Direct
MISSION DURATION: 10 days nominal
PRIMARY LANDING SITE: Kennedy Space Center, FL
ABORT LANDING SITES: TAL (Prime) - Zaragoza, Spain
TAL Alternate - Moron, Spain
Ben Guerir, Morocco
VEHICLE DATA
ORBITER: Columbia OV-105 (7th Flight)
EXTERNAL TANK: ET-65
MAIN ENGINES: 2012, 2034, 2032
POWER LEVEL: Nominal...........104%
Abort....................104%
To Avoid Ditching........109%
SRBs: BI-067
SRM Set Nr.: Left - 360W040A
Right - 360W040B
SRM Cases: Lightweight/Redesigned
CREW
COMMANDER: Michael Baker
SHUTTLE PILOT: Terrence Wilcutt
PAYLOAD COMMANDER: Thomas Jones
MISSION SPECIALIST: Steven Smith
MISSION SPECIALIST: Daniel Bursch
MISSION SPECIALIST: Jeff Wisoff
1.0 STS-68 LAUNCH ATTEMPT SUMMARY
The scheduled launch of STS-68 on August 18, 1994 was aborted on Launch Pad 39A
(MLP-1) at the Kennedy Space Center (KSC) shortly after the main engine start
command was issued. The on-pad abort occurred at approximately 5:54 A.M.
Central Daylight Time (CDT) (094:230:10:53:58.157 GMT). The abort was executed
because of a ME-3 Failure Identification (FID) due to the High Pressure
Oxidizer Turbopump discharge temperature exceeding a redline. The
investigation of the abort is discussed in section 2.3.
2.0 LAUNCH COUNTDOWN AND ON-PAD ABORT
2.1 SOLID ROCKET BOOSTERS - SRBs BI-067, RSRMs 360W040A, 360W040B
The SRB prelaunch countdown was normal. There were no SRB Launch Commit
Criteria (LCC) violations. There were no SRB Operational Maintenance
Requirements Specification Document (OMRSD) violations other than the left hand
system 'A' Range Safety battery temperature dropped off scale low. All other
Solid Rocket Booster (SRB) systems performed as expected.
No RSRM Launch Commit Criteria (LCC) or Operational Maintenance Requirements
Specification Document (OMRSD) violations occurred. Power up and operation of
all igniter, and field joint heaters was accomplished routinely. All RSRM
temperatures were maintained within acceptable limits throughout the countdown.
2.2 EXTERNAL TANK - ET-65
All objectives and requirements associated with External Tank (ET) propellant
loading and were met. All ET electrical equipment and instrumentation operated
satisfactorily. ET purge and heater operations were monitored and all
performed properly. No ET LCC or OMRSD violations were identified.
Typical ice/frost formations were observed on the ET during the countdown.
There was no observed ice or frost on the acreage areas of the ET. Normal
quantities of ice or frost were present on the LO2 and LH2 feedlines and on the
pressurization line brackets. These observations are acceptable per NSTS
08303. The Ice/Frost "Red Team" was not used based on a recent change to the
LCC. The Debris team reported nothing unusual on the ET.
The ET pressurization system functioned properly throughout engine start.
2.3 SPACE SHUTTLE MAIN ENGINE - SSMEs 2012, 2034, 2032
All SSME parameters appeared to be normal throughout the prelaunch countdown
and were typical of prelaunch parameters observed on previous flights. Engine
"Ready" was achieved at the proper time and all LCC were met.
2.3 SPACE SHUTTLE MAIN ENGINE - SSMEs 2012, 2034, 2032 (cont)
The on-pad launch abort occurred because the ME-3 (E2032) High Pressure
Oxidizer Turbine (HPOT) discharge temperature Channel A exceeded a pre-liftoff
redline check resulting in a Failure Identification (FID) and subsequent engine
shutdown. At Engine Start Command (ESC) plus 2.3 seconds through ESC plus 5.8
seconds the HPOT discharge temperature must not exceed 1560 R. The ME-3 HPOT
discharge temperature Channel A was 1576 R. The Channel B measurement was 1530
R which was also higher than predicted. Instrumentation/data appears to be
valid.
ME-3 was commanded to shutdown at ESC plus 4.72 seconds. ME-2 and ME-1
subsequently shutdown at ESC plus 5.80 seconds and 6.96 seconds respectively.
The shutdowns were all nominal and placed the vehicle in a safe status.
The cause of the high turbine discharge temperature is under investigation and
a number of factors could in combination have led to the overshoot temperature
response (e.g. fuel side build-up characteristics, sequencing changes prior to
STS-68, turbopump efficiencies, hardware degradation, etc.). The current plan
of action is to establish investigation teams, perform fault tree analysis,
engine inspections and detailed data and film evaluation.
2.4 MAIN PROPULSION SYSTEM - MPS OV-105
The overall performance of the Main Propulsion System (MPS) was as expected.
LO2 and LH2 loading were performed as planned with no stop flows or reverts.
There were no OMRSD or LCC violations.
Throughout the period of preflight operations, no significant hazardous gas
concentrations were detected. The maximum hydrogen concentration level in the
Orbiter aft compartment (which occurred shortly after the start of fastfill)
was approximately 153 ppm, which compares favorably with previous data for this
vehicle.
A comparison of the calculated propellant loads at the end of replenish, versus
the inventory loads, results in a loading accuracy of -0.026 percent for LH2,
and +0.035 percent for LO2.
MPS performance during engine start and shutdown appeared to be as expected.
2.5 SHUTTLE RANGE SAFETY SYSTEM - SRSS
Shuttle Range Safety System (SRSS) closed loop testing was completed as
scheduled during the launch countdown. All SRSS Safe and Arm (S&A) devices
were armed and system inhibits turned off at the appropriate times. All SRSS
measurements indicated that the system operated as expected throughout the
countdown with the exception of the left hand system A battery temperature.
The system A battery temperature was erratic between nominal (approximately 78
degrees F and off scale low (18 degrees F). An exception was written to the
OMRSD requirement of 34.6 to 103.4 degrees F.
All SRSS devices performed as planned for an on-pad launch abort.
3.0 CANDIDATE IN-FLIGHT ANOMALIES AND SIGNIFICANT PROBLEMS
The ME-3 (E2032) redline exceedance discussed in paragraph 2.3 is the only
candidate MSFC In-Flight Anomaly (IFA) associated with MSFC hardware identified
at this time.