- Status Report
- Jan 29, 2023
Minutes for December 12, 2000 EVA AIT
From: XA/Nancy J. Patrick
Subject: Minutes for December 12, 2000 EVA AIT
The EVA AIT met at the Johnson Space Center on December 12, 2000. Boeing/Lou Ramon and XA/Nancy Patrick co-chaired the meeting. Representatives from CB/Flight Crew Operations, XA/EVA Project Office, NC/Flight Systems Safety and Mission Assurance, DX32/EVA Systems/Mission Operations, OC/ISS Logistics and Maintenance, EA/Systems Engineering Office, ES/Engineering Structures and Mechanics Division, USA/Flight Crew Equipment, and Boeing-Houston (EVA, Operations, and Safety) were present. Representatives from the Boeing Development Centers supported by telecon. Copies of presentations can be obtained from XA/Charlotte Shannon, Building 1, room 661, (281) 483-5259.
1. Introduction/AI Review Boeing/Lou Ramon
The Following Decision Packages were dispositioned (distributed November 28, 2000):
D-00046B: Spar Dexterous Handling Target Sharp Corners
Decision: The EVA AIT approved this waiver
NCR-EVA-FPP-01: Floating Potential Probe does not meet EVA kick loads requirement
(XA/Nancy Patrick to report final disposition and results of structural analysis to determine if load limiter relieves before the stanchion sustains damage)
Decision: Ms. Patrick reported that OB/John Zipay signed the NCR after the analysis demonstrated that the load limiter would protect the stanchion if kicked. Ms. Patrick therefore approved and signed the NCR for the EVA AIT.
1. Introduction/AI Review Boeing/Lou Ramon
The Following Action Items were reviewed:
AI-507: This action remains open and will be addressed again on January 16. Based on the results of the general stowage discussion (see minutes below), the action will be changed to report the 4A post-flight stowage results and the 5A stowage plans and whether there are any further 5A assessments are required.
AI-510: This action remains open and will be addressed again on January 16. There was no update.
AI-511: This action remains open and will be addressed again on January 16. There was no update.
AI-513: This action was CLOSED. Mr. Nordvedt and Mr. Farrell described the predicted action of the TUS cable should it be released inadvertently and there are no concerns with either the safety or feasibility of the operation. The cable will retract up to 13 inches into the reel assembly if released, and the drag brake stops reel rotation as soon as tension is released. Some slack may develop between the control arm sheave and exit sheave, however this is not a concern to the operation of the reel. The EVA AIT felt that there are options for controlling the cable while it retracts, and the details of the procedure will be developed during flight development and crew training.
AI-522: This action was CLOSED. ES/Katherine Davis reported that she has been working with Huntington Beach to develop and implement a test plan for EVA bolts using Loctite as a locking feature. Phase 1 of the testing should be complete by the end of the year, with additional testing using the 6B boxes in the spring. The EVA AIT agreed that no further formal tracking of the issue is required, and requested that Ms. Davis report the results of the spring tests after they are complete.
AI-542: This action was CLOSED. Mr. Looper reported that DX32 plans to update the EVA Console Handbook to include a list of items/actions required when any new EVA task is requested in real time. The thermal assessment is one of the items on the list. This satisfies the intent of the EVA AIT action and therefore it was closed.
AI-543: This action remains open and will be addressed again on March 13 after the EMU extended contact temperature testing is complete. If the EMU re-certification achieves the current predictions, it will not be necessary to perform a special report for the flight tasks that require extended contact. The standard thermal assessments should cover any concerns. This action will be closed when the EMU testing is complete (scheduled for 2/19/01) if the test results are as expected.
AI-546: This action was CLOSED. Based on the report, the EMU re-certification target temperatures for extended contact are correct. See minutes below for additional information.
AI-547: This action was CLOSED. EC5-ILC/Maria Garza provided a schedule/plan that outlined the various test preparation and testing steps required to determine the appropriate contact pressures and EMU extended contact temperature capability. The testing and data analysis should be complete and the HSMS/ILC report released by February 19, 2001. When asked, Ms. Garza replied that a formal delta-certification could be provided 3 to 4 months after the report was released. Ms. Patrick noted that the delta certification was required and requested that be added to the plan. Ms. Patrick closed the action and scheduled a presentation on the test results for the February 20, 2001 EVA AIT.
AI-552: This action remains open and will be addressed again on January 16. Mr. Ramon reported that B-Hou/Davey Moore is looking into the issue, but was tied up with STS-97 until now.
AI-555: This action remains open and will be addressed again on January 16. There was no report, as Mr. Carlton was tied up with STS-97 as well.
AI-556: This action remains open and will be addressed again on January 16. The presentation was deferred because Mr. Adams was on travel and no one knew the status of his work.
AI-560: This action remains open and will be addressed again on January 16. Mr. Price reported that B-HB/EVA has developed a list of worksite analyses that have been performed to satisfy verification of required contingency tasks, and is coordinating with the B-HB safety organization to ensure that all tasks are covered. B-HB does agree to the principle that if a task is required to meet redundancy or safety requirements, Boeing will perform the worksite analysis to verify the task.
AI-563: This action was CLOSED. Mr. Harless provided most of the analyses requested. The rest will be done during SSCN 3370 development but will not be tracked formally by the EVA AIT. See minutes below for additional information.
AI-564: This action was CLOSED. Ms. Patrick reported that the EVA hardware group was informed of the new hardware development effort and agreed to participate. Ms. Patrick reported that Steve Broussard is the XA point of contact for both the SSCN 3370 cables and the alternative attachment method.
AI-565: This action remains open and will be addressed again on January 16. Mr. Wolf and Mr. Guirgis were called in for STS-97 flight support when the test was scheduled. Mr. Guirgis will reschedule the test and report back to the EVA AIT.
AI-567: This action remains open and will be addressed again on January 16, however the Actionee will be changed to EC5/Chi Minh Chang. Mr. Messinger reported that LMES developed the PIRN and submitted it to Mr. Chang for approval prior to submitting it to the ICWG for formal program review.
2. ISS EVA External Stowage Assessments and Process XA/Nancy Patrick, All
There was no presentation material for this topic. Participants used the questions outlined in the agenda to guide the discussion. The following resulted.
Are the NBL mockup/engineering units of the ETSDs and external bags of sufficient fidelity to determine whether new items will fit?
- Engineering and USA/FCE representatives reported that the NBL trainers and engineering units currently in inventory were built to the flight drawings and therefore are of sufficient fidelity for stowage assessments. All EVA AIT participants agreed.
Are the training tools of sufficient fidelity to support a stowage assessment? (Engineering/MOD)
- Yes, the volumetric tools are of sufficient fidelity for stowage assessments.
Who sets up a stowage evaluation and who needs to be involved in it? Who ensures the tools and mockups are available to support the evaluation?
- MOD agreed that they have the responsibility to schedule and conduct stowage evaluations, including scheduling the tools and stowage devices. Crew and MOD are the primary participants in the stowage assessments. XA and EC participants will be included as required.
How do we keep up with multiple flight configurations in the planning phase to allow assessments of later?
- XA/Barbara Counts noted that the on-orbit ESEL reflects future flight configurations as they are developed. This information is usually provided through the flight ESEL development process, from the up/down quantities. Therefore the system is in place as long as people provide the information. While changes will come in to earlier flights that affect previous assessments/plans made for later flights, the information will at least be available to identify those impacts.
In summary, the flight EVA IPT leads will present proposed stowage configurations to the EVA AIT to ensure global support for the proposal. Stowage assessments will then be conducted by MOD using currently available NBL and training units. XA will track stowage plans through the on-orbit ESEL process. XA flight EVA IPT leads will be responsible for ensuring that stowage plans are adequately evaluated with the current planned configuration from the previous flight, and communicating their flights stowage plans to later flight IPT leads. If flight specific stowage plans change significantly from what was previously approved by an EVA AIT, XA EVA IPT flight leads should present the changes to the EVA AIT. This process will depend on all EVA community participants doing their part to fulfill their technical responsibilities for stowage evaluations and to provide the required information for stowage tracking.
One question came up about on-orbit stowage and tracking. Since the on-orbit APFRs are now different configurations (two had the thermal plates removed to resolve the interference with side mounted WIFs), and one has a faulty pitch joint. No one present knew whether the flight procedures direct specific serial numbers for specific stowage locations, and whether the on-orbit ESEL tracks specific serial numbers so that the different configurations can be tracked. This capability will also be required as individual pieces of EVA equipment vary in performance. Ms. Patrick and DX32/Chris Looper agreed to investigate this question.
Decision: The EVA equipment external stowage tracking process is complete and will be implemented immediately. Plans for externally stowed EVA items will be evaluated through the EVA IPTs and AIT, and tracked through the on-orbit ESEL.
Action 568: Investigate whether flight procedures include serial numbers for stowage location designation and whether the on-orbit ESEL tracks to the serial number (reference APFR differing configurations)
Actionee: DX32/Chris Looper, XA/Nancy Patrick
Due Date: January 30, 2001
Method for Closure: Report to EVA AIT
3. Inadvertent Contact Load (125lb-f kick load) EC5/Lora Bailey
Requirement – History and Rationale
Ms. Bailey reviewed the history of the development of the Inadvertent Contact Criterion and explained the subtleties and limitations with the criterion. The purpose of reviewing that information was to establish an acceptable process and criteria for reviewing requests for exceptions for hardware meeting the criterion.
The inadvertent contact criterion is often thought of as a kick load, however Ms. Bailey explained that the contact criterion is intended to include all forms of inadvertent contact induced by an EVA crewmember. The criterion is primarily based on a KC135 test where a crewmember kicked an instrumented plate with a realistic force. Over 100 data points were taken over 3 parabolas of testing. The data points were plotted using a peak force vs. pulse width (as defined by a half-sine wave pulse) plot, with the intent of producing a linear interpretation of data to yield a variable forcing function as a bound. Interpretation of the data plot showed that most of the data points were enveloped by a line bounded by a peak load of 125lb and pulse duration of .2 sec. The slope of the line was determined by the intersection of a horizontal line at approximately 75lb (under which most of the data points reside) and a vertical line of .2 sec (to the left of which most of the data points reside). The 125lb upper boundary for the final resultant line for which the requirement is came from the fact that it covered all but one of the points above the 75lb horizontal line (the highest load was approximately 135lb and the next highest was approximately 105lb).
Ms. Bailey noted that for ISS the requirement is to protect against a 125lb, quasi-static concentrated load over a .5-inch diameter circular area. The requirement is applied within 24 inches of a translation path or worksite, in any direction. Ms. Bailey noted that while the load of concern is really a dynamic load, the cost of analyzing against a dynamic load made a dynamic load requirement prohibitive. Therefore for ease of analysis and verification, the quasi-static load requirement was developed, and the high peak load accounts for some of the conservatism lost by not assuming a dynamic load. Ms. Bailey cautioned against assuming that that the requirement is overly conservative, however, because of this compromise.
Ms. Bailey then reviewed the additional considerations that could affect the definition of an acceptable inadvertent contact criterion, which have been used to evaluate cases where the requirement cannot be met without a prohibitive cost. The considerations include the probability of contact, probability of the type of contact, probability of specific load conditions, operational workarounds available, and impacts of exceeding the hardware capability including hardware criticality.
The EVA AIT concluded that while we have used much of the same criteria to evaluate exceptions to the inadvertent contact load in the past, structures and mechanisms representatives should be consulted in evaluating these exceptions. ES/Katherine Davis has been assigned to follow the EVA AIT and agreed to participate in these evaluations. Ms. Davis agreed to participate in the tiger team effort to address the FRAM/ORU integration issue. Ms. Patrick agreed to provide Ms. Davis with a list of all kick load exceptions approved by the EVA AIT to ensure the correct decision was made.
Decision: The EVA AIT concurred with the criteria provided for assessing and approving exceptions to the inadvertent contact criterion (kick load requirement) and that a representative from ES/Structures division should be consulted on future exceptions.
Actionee: XA/Nancy Patrick
Due Date: January 30, 2001
Method for Closure: Report to EVA AIT
4. SSCN 3370 RS Laptop Cable routing B-Hou/Dennis Harless
Mr. Harless provided two options for cable routing from the FGB connectors to the airlock connectors. For each routing option, he provided graphical representation of a routing path that ties directly to handrails and one that is offset from the handrails. Option 1 is the most direct option and requires 57 ft line for the handrail routing and 55 ft for the offset routing. Option 2 requires a longer routing path and appears to be along the Node primary translation path and the Node endcone translation path. Therefore the EVA AIT preferred option 1 over option 2. The EVA AIT recommended that the Option 1 handrail path be used to drive the cable design, since that cable length can be used for either the handrail or the offset options.
Mr. Harless did not provide a routing option that utilizes MMOD shield connectors because that idea had not been communicated to him. The EVA AIT concluded that further routing definition and options should be worked with EV/Dave Pruett through the SSCN 3370 team. The EVA AIT will not formally track any further work on the cable development, however the team can bring forward to the EVA AIT any EVA issues requiring resolution that come up during SSCN 3370 development.
Decision: The EVA AIT recommended the handrail routing path for the Option 1 cable routing be used for SSCN 3370 cable design (i.e. 57 foot length requirement). Further cable design and cable routing decisions will be handled through the SSCN 3370 development team (that includes EVA AIT members).
Action Item Closure: AI-563 was CLOSED.
5. Thermal Assessment of EMU Temperature Range ES/Jay Leggett
There was no presentation material for this topic. Mr. Leggett reported that for the temperature range expected for the EMU certification, only MMOD shields and nickel-plated Zero-g connectors. This hardware primarily violates the 240°
F limit at |
angles greater than 60°
, for end of life thermal properties. Only the connectors that dont have thermal covers or tape violate the temperature range. (At a previous EVA AIT, the operating limit for zero-g connectors was reported as 270°
F, so thermal protection should be in place for any connector predicted to exceed that temperature).
Based on this report, the EVA AIT concluded that the proposed EMU re-certification effort is still worthwhile and will accommodate most of the ISS EVA requirements. For hardware that exceeds the re-certification temperature range, specific operational analysis may be required, and operational controls may be required to make sure the EVA crewmember is not exposed to a hazard. The specific conditions under which the hardware exceeds the range will need to be documented in NCRs, with proposed operational workarounds included.
After the EVA AIT, B-Hou/Ryne Baker clarified Mr. Leggetts report. He clarified that there is hardware that does exceed the predicted EMU temperature range at lower |
, before end of life, for example the PMA shields. All agreed however that the conclusions about the value of the EMU re-certification effort, and the process for addressing violations of the re-certification limit, are still valid. However Mr. Bakers comments pointed out that previously approved NCRs on touch temperature limits will have to be addressed to determine when they exceed the EMU re-certification temperature range. This will be discussed once the EMU testing is complete and we have concluded that the re-certification temperature range is valid.
Decision: The EVA AIT concluded that the proposed EMU re-certification effort would accommodate most of the ISS EVA requirements. NCRs will document the specific conditions under which the hardware exceeds the re-certification limits, and operational evaluation of the task requirements and operational controls available will be instigated when those conditions exist.
Action Item Closure: AI-546 was CLOSED
6. Pump Module Assembly (PM-A) PIDS exception PG1/Dan Pankratz
Mr. Pankratz presented PIDS exception PG1-S1-1212-99: S1 EVA External Limit Load Exception Pump Module Assembly, and requested immediate EVA AIT review. The exception requests a waiver to the verification requirement for the PM-A EVA task. The verification currently requires a ground demonstration of the PM-A installation. There was no other presentation material for this topic.
Mr. Pankratz explained that the PM-A was installed at KSC without all of the surrounding structure in place and therefore the SVITO representative would not sign off on the acceptance test procedure for the PM-A remove and replace EVA task. Mr. Pankratz explained that the Ground Support Equipment (GSE) supports required for PM-A installation interfere with the surrounding hardware. That is why surrounding hardware cannot be in place when the PM-A is installed on the ground. Unfortunately no SVITO representatives were present to explain their position, because they were not informed that Huntington Beach was going to request the discussion at the EVA AIT. Mr. Pankratz thought that their only concern was that the surrounding hardware (primarily MLI blankets) was not present. Mr. Pankratz did not indicate there were any issues identified by SVITO, just that the configuration didnt meet the generic test requirements. Mr. Pankratz did not know what the SVITO proposal was for resolving the issue, however he surmised that they recommended an installation with the full surrounding structure in place. Huntington Beach wanted to get an EVA AIT position on the exception immediately because the PM-A was due to be removed on 12/15 and would not be re-installed until late 2001. Any requirement for additional evaluation involving installation of the PM-A between 12/15 and the re-installation date would be an impact to the S1/P1 launch schedule.
The EVA AIT conceded that if there is a GSE interference, it is impossible to install the PM-A after all the surrounding structure is in place, and therefore not possible to fully assess the PM-A remove and replace EVA task with the ground installation activity. However the EVA AIT suggested that a combination of witnessing the PM-A ground installation/removal activity and a later "static" inspection of the hardware, with all surrounding structure in place should suffice. The entire verification requirement cant be closed until the later static inspection, however the EVA installation test paperwork could be closed in this plan. The EVA AIT suggested that if the SVITO did not feel that they had properly witnessed the previous PM-A installation activity to support this alternate plan, Huntington Beach should work with SVITO to provide a re-installation activity as part of the removal activity scheduled for 12/15. Since SVITO was not at the EVA AIT discussion, Ms. Patrick requested that Huntington Beach coordinate this proposal with them to ensure that all their concerns are satisfied. In addition, Ms. Patrick requested that Huntington Beach coordinate this proposal with other interested parties who were not in attendance, including XA/Beth Stubbings and Jeff Dutton, and DX32/Chris Looper and Oscar Koehler.
Subsequent to the EVA AIT, Ms. Patrick and Mr. Dutton learned that SVITO did not require another PM-A installation activity and they agreed with the static inspection at a later data. However SVITO believes there is a real hardware interference between the MLI and the PM-A for the on-orbit installation task. The EVA AIT will meet in a splinter session to discuss the hardware testing required, the open paperwork that should be carried and the design efforts required to address the hardware issue identified by SVITO.
7. Upcoming Events/Future Agenda Review XA/Nancy Patrick, All
Ms. Patrick reviewed the preliminary EVA AIT agenda for January 2, 2001. Several EVA AIT members are not available on that date, and all participants agreed that the topics scheduled could be deferred until January 16. Presenters were requested to confirm agenda topics by COB Thursday, January 11.
There will be no EVA AIT on January 2, and there will be a Crew Consensus Issue review held January 9.
The Following Topic was deferred until January 16
Results of 7A, 7A.1 Flight Thermal/Task Analysis DX32/Bob Adams
and revisit of 5A 6A for critical maintenance tasks
Present results of 7A, 7A.1 task analysis, comparing the extended contact tasks against their thermal environments. Report tasks that may require extended contact and when they exceed the -145°
F to +240°
F envelope. Discuss any available operations workarounds to deal with the temperature exceedances. Report on assembly, contingency and critical maintenance tasks (tasks for which spares are available for those flights/increments). Report critical maintenance tasks for 5A, 5A.1 and 6A
Decision Required: EVA AIT concurrence with acceptability of flight plans.
Required Attendees: XA, Boeing-Houston, DX32, CB, NC, EC5, KSC/SSHIO, PGs, SLP, MSFC
Action Item Closure: AI-556