Minutes for December 11, 2001 EVA AIT
To: Distribution
From: XA/Nancy J. Patrick
Subject: Minutes for December 11, 2001 EVA AIT
The EVA AIT met at the Johnson Space Center on December 11, 2001. Boeing/David Read and XA/Nancy Patrick co-chaired the meeting. XA/Heather Mitchell was the NASA chair for items 3 and 4. Representatives from CB/Flight Crew Operations, XA/EVA Project Office, DX32/EVA Systems/Mission Operations, NT/Flight Systems Safety and Mission Assurance, OB/ISS Vehicle Office, DF/MOD Systems Division, and Boeing-Houston, (EVA and Safety) were present. Representatives from the Marshall Space Flight Center, and Boeing-Development Centers (Canoga Park, Huntington Beach, Huntsville) participated by telecon. Copies of presentations can be obtained from XA/Donna Ezzell Building 1, room 641, (281) 483-6771.
1. Introduction/AI Review Boeing/Dave Read
XA/Nancy Patrick
The Following Decision Packages were dispositioned (originally distributed November 13, Revision distributed December 10):
S0 Fit Check Matrix Update: The revised fit check matrix, distributed by email on December 10 was approved for re-baselining.
The Following Action Items were reviewed:
AI-637: This action remains open and will be addressed again on February 5. Mr. Larsen reported that the TPS to fix the MBS guide vane bolts has been approved and is in work. Mr. Larsen is working on a TPS to fix sharp edges found on the P3 guide vanes during other testing. He reported that no sharp edges were found on the P3 capture latch. He reported that a TPS is required to institute a fix to the sharp edges discovered during the P3 testing because the outboard test team QA representative at KSC did not want to accept a PR on them since the hardware was built to print. Ms. Patrick requested that PG1/Larry Price consult Larry Anderson on this process. Ms. Patrick is concerned that if PRs are not taken during the testing, there is no open paper against the hardware that needs to be fixed and unless a follow-up TPS is written, the required fixes will not be incorporated into the hardware processing schedules and may not be done. Mr. Larsen will report on the status of the TPS’ development and the plans to excecute them in February, and Mr. Anderson will report on the process for documenting sharp edges found during testing.
AI-643: This action remains open and will be addressed again on January 8, 2002. Ms. Patrick reported that Ms. McPhail has scheduled a meeting for Tuesday, December 18 with engineering, Boeing, and operations personnel to address the operational needs for and capabilities of the RAD.
AI-646: This action remains open and will be addressed again on February 5. Ms. Caro provided a copy of the existing sharp edge requirements in SSP 50021 and an updated requirement proposed in the draft EVA design requirements and considerations document. The draft document is not intended to be applied to ISS since it would be a significant change (and therefore cost) to the existing EVA requirements, however it does provide the proposed wording change required for the sharp edge requirements. PG3/Tom Hagale reported that 50021 is not an applicable document in the ISS requirements tree either — it is a compilation/duplication of safety requirements found in other documents that are applicable, so a change to 50021 would not be sufficient to drive any changes to ISS. Ms. Patrick requested that Ms. Caro investigate the applicable requirements in the USOS and the ISS segment specifications, and consider initiating an SSCN to these documents that exempts all elements with a baselined PIDS. Ms. Patrick agreed to provide Ms. Caro a copy of SSCN 1930 as an example, which used the same approach to update the USOS and ISS segment spec to provide EVA handholds for robotic based worksites without impacting the baselined elements.
AI-647: This action remains open and will be addressed again on January 22. B-Hou/Curt Carlton will be added as an actionee. Mr. Boller reported that Canoga Park had agreed to update the OP-01 and LSAR procedures to include a warning for the Z1 and P6 fasteners for any procedure that requires actuation of the fasteners. They do not plan to include the warnings for any future element procedures that operate these type fasteners. Mr. Boller explained that it is Canoga Park’s belief that the failure can only occur if the fastener is not assembled properly and we had already agreed that the changes to their ground assembly procedures were sufficient to preclude future errors. Ms. Patrick explained that Mr. Carlton indicated in the last discussion that the failure could occur upon actuation of an otherwise good fastener. Mr. Boller explained that the fastener Mr. Carlton was referring to is a different fastener than the ones covered by the SCAN. Therefore they have not added any warnings associated with operations of that type fastener (an example of a location for this type fastener is on the mast canister handling tool). That brought up the question of whether there should be warnings for those fasteners, especially since the failure/hazard can occur from on-orbit operations. Mr. Boller and Mr. Read agreed to work with Mr. Carlton to provide a Boeing consensus on whether the crew can induce the failure on-orbit or not. They also agreed to provide a recommendation on whether the other type of fastener (not included in the SCAN) requires a warning when it is operated.
AI-649: This action was CLOSED. Mr. Read provided the downstream flight operations involving the connectors and the configuration changes that might affect the operations. See minutes below for additional information.
AI-650: This action was CLOSED. See minutes below for details.
AI-651: This action was CLOSED. See minutes below for details.
2. Lab Connector/Receptacle Spacing Concern for S0 B-Hou/Dave Read, OB/Bryan Coulombe
Rigid Umbilical Connections
Mr. Coulombe provided a brief history/summary of the interface testing done to date, and why the connector spacing concern didn’t surface before now. Mr. Coulombe reported that prior to the Lab launch, a mate/fit check only was performed. This test only includes mating umbilicals to ensure the connectors match up and can be mated to their receptacles. The lab MMOD shields were not present in that test because they weren’t available at the only time the mate/fit check could be done without impacting schedule. No one noted a concern with the shields, probably because the final shield configuration was not yet known. For the 7A.1 S0 LTA cable assessment, an OOCT was performed, but only by analysis. The primary focus of the 7A.1 assessment was to address cable routing and cable length, since the connector mating was done as part of the 5A mate/fit check. Therefore the 7A.1 assessment didn’t identify the shield interference either. The 8A test was the first full-up OOCT test, using the lab emulator and the S0 tray/rigid umbilical flight article. The lab emulator had foam installed to simulate the MMOD shields, the clearance issue was identified and the PRs were opened. Mr. Coulombe provided pictures of the testing that showed gloved hand access to the connectors in the area of the shield.
Mr. Read presented information concerning general OOCT requirements and history, future operations that interface with the lab receptacles in question, options for addressing the lab clearance issue, and recommendations for future OOCT. Mr. Read noted that verification of the 1.6" connector clearance requirement is not a standard part of OOCT testing procedures. The verification of this requirement for inter-element connections is the responsibility of Boeing-Houston, however this clearance issue was not identified as part of that verification.
Mr. Read also reported that in addition to actuating two of the connectors on 8A to remove the LTA cables and connect the S0 cables (J14 and J118), connector P702 is disconnected from Lab receptacle J118 and then mated to Node 2 on flight 10A. There are no further planned operations for these connectors/receptacles. Additionally, P701 is disconnected from Lab receptacle J119 and mated to Node 2 on flight 10A. There is no PR open associated with this connector/receptacle, however no one present knew whether that was because it was evaluated and meets requirements or whether the clearance violation hasn’t been identified yet. Mr. Coulombe reported that the connector/receptacle was exercised in the S0/8A test, as were all the Node 2 connections but only with Node 2 connectors and umbilicals, not with a Node 2 flight article or emulator. Mr. Read stated that the clearance will be assessed as part of the 10A worksite analysis.
Finally, Mr. Read noted that there is a configuration change between the 8A and 10A operations of these receptacles. The Lab ETVCG is installed on flight 9A, and it sits next to the connectors. It may affect the body positioning required to actuate the connector, but it does not result in another 1.6" connector clearance violation.
Mr. Read recommended that the PRs be closed for 8A since the 8A operations were evaluated and approved by the test team, including the crew office representatives present. Mr. Read recommended MOD include a note in the EVA checklists for both 8A and 10 that there is clearance violation/concern with operating the connectors. Mr. Read also recommended that OOCT testing add verification of the 1.6" connector clearance requirement to their standard test procedures. Finally, he recommended that future OOCT tests should include the MMOD shields in the test configuration. The EVA AIT approved all of Mr. Read’s recommendation, and further added that based on our evaluation of the photos available, the PRs can be closed entirely (we concluded that the ETVCG should not interfere with the connector operations on 10A, but even if it does, the ETVCG can be temporarily moved to another camera port). Mr. Read will send an email to the MOD EVA leads for 8A and 10A to request a note in the checklist that warns of the clearance issue, and he will work with Mr. Coulombe to incorporate connector spacing evaluations in future OOCTs.
Decision: The EVA AIT recommended closure of PRs BHB-TRUSS-S0-MECH-P384 & P385 for all flights (lab receptacle connector spacing violations for S0 and Node 2 umbilical connections, 8A and 10A flights affected). The EVA AIT also recommended adding connector spacing evaluations to OOCTs and including MMOD shields in OOCTs whenever possible.
Action Item Closure: AI-649, 650, 651 were Closed
3. Spare PVR (P6 EEATCS Radiator) On-orbit Stowage XA/Nancy Patrick
After P6 relocation
Ms. Patrick reported that the External Carriers Working Group has begun working on a carrier for the spare PVR currently in use on P6. B-Hou/Gary Graybeal presented preliminary information on the locations available and the preferred options to the Configuration Working Group on December 6. The CWG requested preliminary evaluation of the preferred locations, and a list of any issues or assessments that must be performed to approve the locations proposed.
The ECWG prefers not to use one of the designated CAS spots as a permanent stowage location, however wants the platform to be CAS compatible for temporary stowage, both to allow a temporary stowage location and to allow using the MBS CAS during platform relocation when the spare must be used. Therefore the preferred PVR carrier stowage mechanism/location is to use the element trunnions through the Universal Trunnion Adapter system interfaces. Mr. Graybeal reported that for various reasons, the P5 or S5 trunnion locations are preferred by ISS and the ECWG, therefore requested an evaluation of those sites.
Ms. Patrick proposed the following list of required analyses for the CWG:
- EVA primary and secondary translation path assessment
- CETA cart translation corridor infringement assessment
- P5/S5 worksite impact assessment
DX/Chris Looper noted that P6 and S6 maintenance scenarios may be affected by the proposed location, so this assessment was added to the list.
Ms. Patrick requested inputs by email from anyone by Wednesday, December 12, to support the CWG community review on December 13. No one provided any further concerns or assessments required.
Note: At the CWG on December 13, the following assessments were also added to the list, generated from other CWG participant inputs and concerns:
- Worksite analysis of Installation onto and removal from the platform
- Worksite analysis of power connections and cable routing to provide power to the PVR/platform
- Assessment of impacts to the cable routing for contingency ammonia fill of the PVTCS using the EATCS ammonia servicer
3. Requirements for VR Lab assessments of ORU NT/Mirka Caro
jettison, data requirements for VR model development DX32/Chris Looper
Ms. Caro presented that there are no generic safety requirements covering ORU jettison. Minutes from the 4/8/98 SRP, Flight 4A Phase-III and ISS Noncompliance Report (PG2-006) addresses the requirement to protect for jettison of the Solar Array Wing (SAW). The SRP directed the operations community to protect for jettison. MOD developed procedures using the VR Lab to protect the SAW jettison case. Mr. Looper presented a list of mass handling data information that is required to perform VR assessments.
Significant discussion not included in the presentation material:
The consensus is that ORUs over 200 lbs are candidates for EVA handling. XA/H. Mitchell will provide a list of ORUs that should be assessed in the VR Lab. Boeing/David Read agreed to look into what is takes to provide this data to MOD once the list is provided to Boeing. Similar data is used to develop the mass properties for integrated elements. The list will be prioritized beginning with on-orbit ORUs then by hardware launching on subsequent flights. The ORUs will then be assessed in the VR Lab.
Decision: EVA AIT concurs with the plan to provide data for the VR lab and to conduct VR assessments of jettison of ORUs over 200lbs.
Actionee: XA/Heather Mitchell
Due Date: January 22, 2002
Method for Closure: Report to the EVA AIT
Actionee: Boeing/Dave Read
Due Date: February 5, 2002
Method for Closure: Report to the EVA AIT
4. Contingency Segment-to-Segment Mating Task to PG1/Paul Smudde, Steve Gray,
Override SSAS failures, using Payload Retention Devices Kent Rylander, Masood Mehrinfar
Mr. Gray presented the options for using PRDs as a contingency operations control for failure of the SSAS. Two options were presented using the PRDs and new sling straps. Slings are similar to PRDs without the ratchet mechanism. Previous input from the Crew is to minimize the number of PRDs, for EVA efficiency. Option 1 uses 3 PRDs. Option 2 uses 2 PRDs and 2 SSAS EVA bolts to mate the interfaces. Both options require approximately 1.5 hours of EVA time to complete.
Significant discussion not included in the presentation material:
Mr. Gray reported the assessments for S0-to-S1 are essentially complete. Boeing is waiting on a 1-G assessment by MOD and Crew on accessibility to the PRD and sling tie-down points on the S0 and S1 segments. The assessments for S0-to-P1 are incomplete. The location of the MT on S0 can change the tie-down points for the PRDs and slings. The baselined 11A MOD procedures place the MT in the starboard end bay of S0.
EVA AIT operations evaluation of the PRD task will be closed once MOD and Crew are satisfied the tasks are feasible. MOD and the crew will provide the results of their evaluations to the EVA AIT.
Action 654: Determine if the operations to use the PRDs on S1/P1 are acceptable.
Actionee: DX32/Chris Looper
Due Date: January 8, 2002
Method for Closure: Report to EVA AIT
Actionee: PG1/Steve Gray
Due Date: January 8, 2002
Method for Closure: Report to EVA AIT
6. Upcoming Events/Future Agenda Review XA/Nancy Patrick, All
Ms. Patrick reviewed the preliminary EVA AIT agenda for January 8, 2002. Ms. Patrick requested that presenters confirm agenda topics by COB Thursday, January 3, 2002. Ms. Patrick reported that after she sent out the agenda, she received a request to review the FHRC changeout scenarios with respect to the thermal dwell time requirements and whether adjustable struts will be available or long duration tethers are required. This will be added to the final agenda. PG1/Scott Boller requested an informational discussion on the EVA results of a TIM held to address EVA requirements for the robotic off-set tool. Ms. Patrick agreed to add that to the agenda as well.
