XA/EVA Project Office Weekly Activity Report November 1, 2001
STS-110 (8A) S0 Tripod Testing
The 8A EVA team and crew supported the Module to Truss Structure (MTS) strut testing on the S0 Port Tripod structure. Testing was performed on October 4, 2001 in the Sonny Carter Training Facility using structural test articles of both the tripod and S0. Tool clearance were issues identified on four of the six bolts on the S0 strut plate when using a torque multiplier. The EVA crew recommended Boeing review previous analysis and models since a clearance issue was only predicted on one bolt on the tripod plate. Boeing is conducting further thermal testing to determine if the bolt torque values will be high enough to require the torque multiplier.
CoFR2 & SSPCB for STS-108
The EVA Project Office completed the its EVA CoFR2 review for the upcoming STS108/UF-1 flight. All EVA and EMU hardware is on track to be ready to support the flight. The CoFR2 verified that the UF-1 team was ready to support any of the various EVA options the program was considering. A Special SSPCB was conducted to determine which of the options for resolving the Beta Gimbal Assembly (BGA) Anomaly would be pursued. The UF-1 team was directed to stand down from preparing for an EVA to remove and replace the Bearing Motor Roll Ring Module (BMRRM), but rather to prepare for installation of the BGA blanket during an EVA. The SSPCB also decided against starting BMRRM R&R EVA preparation for 8A, UF-2, or any other EVA crew at this time. The remaining UF-1 NBL runs will be used for training the installation of the BGA blankets along with the agreed to get-ahead tasks. The Increment 4 crew will also be trained to conduct the BGA blanket installation task in the event it is not accomplished during UF-1.
High Strength Bridge Clamp (HSBC)
During reassembly of a High Strength Bridge Clamp (HSBC), one of the cap head fasteners was sheared off. The root cause for the failure is that the torque call-out on the assembly drawing is too high and leads to possible yielding of a fastener. There is an HSBC installed on the Payload Bay Sill for STS-108/UF-1, which will be used only for the contingency 96 Bolt Undocking Task. The Structures Group/ES has determined that the UF-1 HSBC is safe to use as-is since none of the fasteners are in the load path during launch or landing, and that the fasteners are not subject to significant cyclic loading during a mission. ES has also concluded that the maximum loading on the fasteners occurred during the assembly, therefore the shearing of fasteners is not likely to occur on-orbit. To resolve this issue, all fasteners on all HSBC units will be replaced, including the UF-1 and on-orbit units once they are returned post-mission. Also, the HSBC assembly drawing will be updated to correct the torque call-outs.
P4/P5/S4/S5 Acceptance Review Board
On October 25, 2001, the EVA Project Office endorsed NASAÕs acceptance of truss elements P4, P5, S4, S5 from the Boeing Company. The elements are well designed, thoroughly tested, and provide good EVA worksites, translation paths, and crew interfaces. The open work remaining on each element includes verification of flight cable lengths and final bolt torques to be performed at Kennedy Space Center. In addition, two significant actions were assigned: the Vehicle Integrated Performance Team will be finalizing thermal and power constraints during EVA assembly tasks, and the Space Station Program will be evaluating the launch of an additional S4 radiator to avoid an EVA relocation from P6.
Certification of Exercise Equipment for Increment EVA Prebreathe
On October 25, 2001 the SMART panel approved use of the ISS Cycle Ergometer Vibration Isolation System (CEVIS) to execute the two-hour exercise prebreathe protocol during increment EVA operations. Physiologic analysis from Space and Life Sciences has shown that a drift in CEVIS cycle resistance does not negate the utility of the exercise protocol. Even if cycle resistance drifts below target values, the resulting DCS protection is greater than any other existing prebreathe protocol. The Safety Review Panel is scheduled to review the SMART panel decision on November 11, 2001.
G. Allen Flynt
Manager
