Status Report

XA/EVA Project Office Weekly Activity Report January 25, 2001

By SpaceRef Editor
January 25, 2001
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Dzus Fastener Trainer and Engineering Development Unit

The EVA Project Office procured a mockup of the Dzus quarter turn fasteners and associated hardware that attach the Micrometeoroid/Orbital Debris shields to the space station modules. There have been instances at KSC when the fasteners have failed or “splayed” in a manner that prohibited the removal of the shields. KSC has developed procedures to avoid this failure mode, but the EVA crew cannot use these procedures because they require tools that are not available or practical for EVA use. Therefore there is a chance that the EVA crew could splay a fastener when reinstalling a shield on orbit. This mockup will be used to train the crew to reinstall the shields to reduce the risk of splaying fasteners. The mockup will also be used to develop a procedure to remove a splayed fastener. Preliminary evaluation of the mockup indicates that the EVA pry bar could be used to remove a fastener, however an additional tool may be needed to ensure success.

Gold Salt Technology

The Hydrazine detection system utilizing the newly developed Gold Salt technology to sense varying levels of contaminant completed all testing required for its flight certification. A color comparison test done at White Sands Test Facility verified that the color templates accurately depicted concentration levels of the Hydrazine contaminant. This device is currently stowed for launch on STS-98 (ISS flight 5A) for use should any crew member be exposed to hydrazine during an EVA.

PFCS to ESP1 Fit Check Resolution:

The External Stowage Platform (ESP) has a Common Structural Interface (CSI) attachment mechanism which mates to one of two Square Grids (SG) on the ESP. It was discovered that a flight-to-flight hardware fit check has not been performed. However, it has been determined that during vibration testing a third flight-like Square Grid was interfaced with the CSI. This third unit has been verified with the as-built flight drawings and was manufactured to the same flight tolerances. Therefore, the fit check will be dispostioned based on a flight-like fit check to the flight CSI.

External Ammonia Quick Disconnect (QD) Training

On January 11, 2000 the EVA Project Office attended an External Ammonia Quick Disconnect (QD) training session conducted by the NASA/Boeing Joint Quick Disconnect Issue Resolution Team (QDIRT). The course was targeted to KSC assembly technicians but contained embedded information regarding potential on-orbit operator-induced failure modes, leakage risks, and do’s and don’ts for setting up EVA pressurized tests to avoid contamination from ground systems. Highlights were:

– QD’s actuated under a side load can exhibit internal galling that may cause leakage. Line routings induce side loads and will be readdressed; EVA cannot guarantee elimination of side loads on-orbit.

– EVA training will be enhanced to identify EVA-visible metal surfaces that contact sealing surfaces after mating.

– The 1.5″ QD is more susceptible to female interlock defeat than previously assumed. A flight-by-flight SRP assessment is in progress.

– – EVA inspection procedures will be updated and provided for EVA training.

ISS Orlan Spacesuit EVA Communications

RSC Energia is continuing to evaluate the results of the unsuccessful Orlan communications checkout conducted January 5th, 2001. RSC Energia is working with their radio sub-contractor and NASA counterparts to determine the likely causes of the interference noted by the ISS crew and ground controllers during the test. Their efforts are currently focused on irregularities in the procedures rather than hardware issues, and a re-test is planned in February, most likely following the STS-98/5A mission. The EVA Project Office has requested that the re-test also include routing the communications to the U.S. on-orbit segment (USOS) S-Band system and Tracking and Data Relay Satellite System (TDRSS) link to demonstrate the capability for more complete communications coverage each orbit.

Original Signed By:

G. Allen Flynt, Deputy Manager

Gregory J. Harbaugh


SpaceRef staff editor.