yee@trident.arc.nasa.gov (Peter E. Yee) (06/03/90)
Friday, June 1, 1990 12:00 noon
Kennedy Space Center Shuttle Status
STS-35 -- COLUMBIA (OV-102) - LAUNCH PAD 39-A
Technicians continue inspections of the shuttle Columbia's
17 inch disconnect area in attempts to isolate a leak in the
liquid hydrogen system that caused managers to scrub Wednesday
morning's launch attempt of Space Shuttle Mission STS-35.
Overnight, technicians offloaded the contents of the PRSD
cryogenic tanks from the orbiter Columbia. Offloading was
completed at about 12:30 a.m. this morning.
A test of the liquid hydrogen system in the orbiter's aft
compartment under higher pressure commenced following PRSD de-
tank operations. Using gaseous helium to help isolate the leak,
engineers detected a higher than normal leak rate in the cavity
between the orbiter and external tank 17 inch disconnect
interface plates.
No leaks were detected between the interface primary and
secondary seals or in the 4 inch feed line seals. However,
leakage was detected in the interface cavity. Engineers will
continue to monitor the situation with hopes of isolating the
exact source and cause of the leak. Trouble shooting on all of
the liquid hydrogen lines in the aft compartment of the orbiter
is continuing.
Based on information assessed overnight, the launch team
will not maintain a launch countdown posture on the pad.
Therefore, launch of STS-35 will not occur next week.
Preparations are currently underway to perform a mini-liquid
hydrogen tanking test next Wednesday morning. In preparation for
this test, a helium signature leak test will be conducted on the
liquid hydrogen side of the main propulsion system Saturday. This
will allow technicians an opportunity to gather additional
information necessary for the accurate placement of additional
leak detection sensors and mass spectrometers. Additional cameras
also will be installed on the pad for more accurate visual
inspections during the tanking test.
Following the helium signature test Saturday, ordnance
disconnect operations will take place Sunday. Prior to
Wednesday's tanking test, the rotating service structure will be
rotated to the park position. The move is scheduled to occur mid-
night Tuesday.
At this time, managers have decided not to open the
orbiter's payload bay doors until further assessments on the
liquid hydrogen line are made. BBXRT does not require servicing
of argon coolant until June 11.
Mission managers will continue to meet to discuss options
for a scrub turn-around based on information established during
current testing.