Click to enlarge this schematic diagram, which details the system used to operate the low-fuel sensors.
In preparation for a Tuesday tanking test to troubleshoot engine cutoff sensors, wiring has been spliced into an electrical harness in Atlantis' aft main engine compartment.
"The attached wiring leads to the interior of the mobile launcher platform where the time domain reflectometry (TDR) test equipment will be located," according to a NASA press release.
Shuttle program manager Wayne Hale described the instrument as similar to devices used to test cable television signals.
On Wednesday in the Vehicle Assembly Building, the TDR was connected to the external tank to be used for STS-123, which is to launch on Feb. 14. This allowed a "dry" ambient temperature signature to be identified.
Friday in Kennedy Space Center's cryogenic test bed facility, TDR instrumentation was exposed to "wet" super-cold temperatures for identifying the signature of a cryogenic environment and calibrating the equipment. On Saturday, the TDR will be taken to the launch pad and installed.
A tanking test is scheduled for 7 a.m. Tuesday to determine where the sensors, wiring or connectors failed on Dec. 6 and 9, forcing launch attempts to be scrubbed.
Low-fuel sensors will be tested Tuesday by fueling the tank with 500,000 gallons of super-cooled liquid oxygen and liquid hydrogen.
In the cryogenic test bed facility at KSC, Time Domain Reflectometry, or TDR, instrumentation was exposed to "wet" super-cold temperatures to identify the electronic signature of a cryogenic environment and calibrate the TDR equipment. The equipment will be used during a Tuesday tanking test on Atlantis.
No comments:
Post a Comment