XA/EVA Project Office Weekly Activity Report May 17, 2001
STS-105/7A.1 Midflow and 7A.1 EVA Assessment Team (EVAAT)
The EVA Project Office conducted the mid-flow review of STS-105/7A.1. There are two scheduled EVA’s on the flight primarily associated with the installation of the Early Ammonia Servicer (EAS), Materials International Space Station Experiment (MISSE) and the S0 launch to activation (LTA) cables. The significant open issues for the flight included possible addition of the Bearing Motor Roll Ring Module (BMRRM) task and the potential for 7A.1 launch prior to 7A. The hardware and training impacts for both cases were presented. The results of the STS-105/7A.1 EVAAT for EVA 1 were presented. The S0 LTA cable transfer task was deferred to EVA 2 so that the EVA 1 timeline would have the appropriate margin. No other significant issues were identified.
Ignition in GSE Regulator
On Tuesday afternoon, May 8, 2001, NASA was notified of ignition within a regulator that was part of a GSE test stand at Hamilton Sundstrand, in Windsor Locks, CT. This test stand is part of a high-pressure oxygen system and is used for testing the Secondary Oxygen Packs (SOP’s) for the EMU’s. All facilities that process EMU’s were put on stand down until further notice. At the time of the incident, SOP S/N 1015 was on the test stand, in cycle testing. A manual isolation valve was closed downstream of the subject regulator at a break point in the testing. Upon returning an audible hissing sound was heard, and it was determined that the regulator was leaking. Following disassembly and inspection of the regulator, evidence of ignition was noted. Two O-rings were charred, with 50 percent of one of the O-rings having been consumed by the fire. After assessing all potential ignition mechanisms, a hazard analysis generated by White Sands Test Facility determined that the ignition was most likely caused by flow friction across the O-rings during leakage. This failure is thought to be isolated to this particular regulator. In addition, USA’s systems have been cycled enough to preclude this same type of event. Therefore, on Friday, May 11, 2001, the flight systems, both primary and secondary, were cleared and considered safe for use.
STS-109 HST Servicing Mission 3B NBL training
A series of training runs were conducted for the STS-109 EVA’s. All 5 EVA’s were trained and evaluated in the NBL. EVA day 3, which replaces the Power Control Unit (PCU), is projected to require about 7 hours to complete, which violates the 6 1/2 hour EVA planning guideline. An exception to this guideline is deemed acceptable due to the development of breakout strategies and the criticality of the task. The remaining EVA’s are projected fit within the 6 1/2 hour guideline.
HTV Delta Preliminary Design Review
XA personnel supported the H-II Transfer Vehicle (HTV) Delta Preliminary Design Review (PDR) by conducting a videoconference to review the EVA Review Item Dispositions (RID’s) associated with HTV. A total of 13 EVA RID’s were written by the joint NASA-NASDA team. All but two of the RID’s were accepted and dispositioned by the EVA working group. The remaining two RID’s address the HTV thruster interference with the Node 2 EVA translation path and the requirement to build a neutral buoyancy mockup for developmental testing and training. These issues will be presented to the HTV Delta PDR board for disposition. Additional telecons and EVA working group meetings are planned to further discuss and resolve these issues.
Bearing Motor Roll Ring Module (BMRRM) Anomaly Resolution Team
The EVA Project Office is participating in an Anomaly Resolution Team (ART) that has been formed to investigate the anomalous behavior of the BMRRM on P6. An EVA remove and replace (R&R) Team was formed as part of the ART and is being led by the EVA Project Office. This team is looking at the various issues related to performing a BMRRM R&R. These issues include: which airlock a BMRRM R&R task should be performed from, new hardware required for the task, power inhibit steps, and safety requirements.
Original signed by:
Michael J. Mankin
for
G. Allen Flynt
Acting Manager
