XA/EVA Project Office Weekly Activity Report August 9, 2001
Contaminated Portable Life Support System (PLSS)
Portable Life Support System (PLSS), serial number 1003, was contaminated on flight STS-104/7A when potassium hydroxide (KOH) leaked from the Extravehicular Mobility Unit (EMU) battery. Upon landing, this PLSS was expedited back to JSC, where United Space Alliance personnel cleaned the contaminated area as well as possible. Because the corrosive effects of the KOH were more wide spread than originally indicated by the on-orbit photographs, the PLSS has been returned to Hamilton Sundstrand. Hamilton personnel are currently disassembling the PLSS in an effort to identify the extent of the damage.
STS-105/7A.1 Battery Logistics
STS-105/7A.1 will launch with two increased capacity batteries (ICB) installed in the EMU’s and three Yardney batteries located in middeck lockers. The two ICB’s will be left on ISS, bringing the total number of ICB’s on ISS up to four. The three Yardney batteries will return on the Shuttle to support contingency EVA’s, if required. Preliminary root cause investigation into the electrolyte leakage has identified that unique processing being exacerbated by inverted stowage is the most likely cause for the 7A anomaly. All batteries, both on STS-105/7A.1 as well as the two stowed on ISS are acceptable for use because they have not been exposed to all of these conditions. Additionally, 7A.1 batteries have had an additional absorbent layer of wicking added to contain any KOH released during use.
CETA CART Cover and CETA Passive Coupler Design Review:
The EVA Project Office supported design reviews for the CETA Cart Cover Upgrade and the CETA Passive Coupler modification. The objective of the CETA Cart Cover upgrade is to accommodate the larger ISS ORU’s. The objective of the CETA Passive Coupler modification is to provide additional capability to accommodate offsets and angular misalignments during coupled translation on the ISS Truss Segment Rails. No major issues were noted and work is in progress to finalize drawings and fabricate flight hardware. Representatives from the Safety, Reliability, and Quality Assurance Office, Flight Crew Operations Directorate, Engineering Directorate, Space Station Program Office, and Mission Operations Directorate supported the reviews.
Electronic Control Unit (ECU) Remove and Replace EVA
The EVA Project Office is evaluating a contingency/maintenance task during Increment 3 to remove and replace an electronics control unit (ECU). The existing plan to perform the ECU change out with the array in 0 degrees was not acceptable to ISS due to power requirements. Analysis and one NBL test was performed to develop an alternate plan. The EVA team is continuing to work toward a plan to conduct the EVA either during the first three weeks in September 2001, or during the third scheduled Russian EVA during Increment 3. The consensus from both the U.S. EVA team and its Russian counterparts concluded there is currently not enough unallocated time during the third EVA to conduct the ECU change out. There is also not the recommended thirty days between the EVA and UF1 that the ISS Program is asking for. A recommendation will be brought forward to the program on performance of the ECU R&R EVA in the near future.
KSC Truss Segment TIM
On July 31, 2001, the EVA Project Office held a truss segment EVA technical interchange meeting with Boeing Extravehicular and Crew Systems personnel at KSC. The TIM included an overview of each truss segment (S0, S1/P1, S3/P3, S4/P4, and S5/P5), with particular emphasis on EVA interfaces and worksites. For most, this was the first opportunity to view the truss segment flight hardware and it was a very valuable experience.
Original signed by:
Stephen C. Doering
Acting Deputy Manager
