EVA AIT Minutes 12 September 2000
To: Distribution
From: XA/Nancy J. Patrick
Subject: Minutes for September 12, 2000 EVA AIT
The EVA AIT met at the Johnson Space Center on September 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, OM/ISS Mission Integration, EC/Crew and Thermal Systems, ES/Engineering Structures and Mechanics, LMES/Thermal, and Boeing-Houston (EVA, Ops, Thermal and Safety) were present. Representatives from the Kennedy Space Center and 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
XA/Nancy Patrick
The Following Decision Packages were distributed for review September 26:
N1-2 MDM Radiator Issue
OM/Jack Bacon requested EVA AIT evaluation of replacing the MDM radiator after DSM docking. The radiator intrudes on the docking envelope for several visiting vehicles that dock to the same port. If the EVA task can be performed after the DSM is in place, only the DSM will have to be modified. Ms. Patrick questioned whether the Huntington Beach work site analysis for the nominal R&R case included the DSM in place, since this should be a required configuration for the maintenance scenario. B-Hou/Lou Ramon agreed to look in to it.
The Following Decision Package was deferred until September 26 (distributed August 29):
PG1-P3/S3-991: EVA Bolt Head Dimensions
Open Work: CB/Fernando Ramos requested information on whether the bolts in question had been fit checked. There was some confusion as to whether these are spares or the initial flight unit, so B-Hou/George Osorio agreed to discuss it with Mr. Ramos off-line.
The Following Action Items were reviewed:
AI-135: This action remains open and will be addressed again on October 24. Ms. Jochim reported that no progress has been made on this action by CSA. Ms. Jochim plans to bring it up with the NASA robotics community to see if they can provide any insight.
AI-504: This action remains open and will be addressed again on October 10. Mr. Boller has not been able to find the information on the P6/S6 WIFs 6 and 28, and the structures analysts have had other priorities
AI-514: This action remains open and will be addressed again on September 26. The PG1 inputs have been provided, however Mr. Ramon has not had a chance to consolidate all the inputs into a single package.
AI-521: This action remains open and will be addressed again on September 26. Mr. Ramon reported for Mr. Harless that he had presented the situation to an MOD forum and that no issues or actions were recorded. Ms. Patrick asked if that implied there is no requirement to install the cable while the MPLM is installed, and that there is no requirement for the cable to be installed when a MPLM must be installed. Mr. Ramon agreed to determine if that question was addressed and if not, he will address it with the appropriate MOD personnel.
AI-527: This action remains open and will be addressed again on September 26. Todays report was a status of the data gathering and exchange. B-Hou/Matt Mickle reported that the FRAM and EVA tools representatives had met, started reviewing the FRAM requirements and would be ready to close the action on September 26.
AI-528: This action remains open and will be addressed again on September 26. Todays report was a status of the data gathering and exchange. B-Hou/Matt Mickle reported that the FRAM and EVA tools representatives had met, however they were still working on the worst case (presumably a battery ORU) ORU data, however they would be ready to close the action on September 26.
AI-529: This action remains open and will be addressed again on September 26. Todays report was a status of the data gathering and exchange. B-Hou/Matt Mickle reported that the FRAM and EVA tools representatives had met, started reviewing the FRAM requirements and would be ready to close the action on September 26.
AI-530: This action is CLOSED. Mr. Osorio reported that the development mockup is not adequate for testing the UMA remove while the CAS platform is stowed. Mr. Osorio preferred waiting until the training mockup is available, which should be within a couple of months of the planned test that this objective would piggyback.
AI-532: This action remains open and will be addressed again on September 26. Mr. Guirgis had not had a chance to incorporate the PG2 comments, and Ms. Tullar was unavailable. Her part of the action will be addressed by XA/Jeff Dutton.
AI-535: This action was CLOSED. NC/Edgar Rivera provided information on all previously approved/evaluated ISS touch temperature NCRs, as well as the process by which the SRP addresses exceedences below 320°
F. See minutes below for additional information
AI-536: This action was CLOSED. Mr. Looper explained how MOD tracks and uses constraints and cautionary information in the flight data file. See minutes below for additional information.
AI-537: This action was CLOSED. Mr. Bue provided information on the Lockheed flight specific analysis and Ms. Patrick summarized the Boeing thermal analysis process presented at the August 22 EVA AIT. See minutes below for additional information.
AI-538: This action was CLOSED. Ms. Patrick reported the status of the EMU capabilities based on discussions with Hamilton Standard representatives. See minutes below for additional information.
AI-539: This action was CLOSED. Mr. Looper presented for DX32/Randy McDaniel the use of the Orlan suit. See minutes below for additional information.
AI-540: This action remains open and will be addressed again on September 26. Mr. Looper had not been able to coordinate the response with the rest of DX32.
AI-541: This action remains open and will be addressed again on September 26. Due to the numerous inputs and versions of the fit check matrices, Ms. Patrick requested that Mr. Gray send out a final, complete version of the FCMs for review on September 26.
2. Touch Temperature Thermal Analysis – Hardware B-Hou/Marconi Nicholls,
Verification vs. EVA execution analysis Ryne Baker, LMES/Grant Bue
Mr. Bue reviewed the scope, schedule and content of the LMES EVA thermal analysis. Mr. Bue explained that LMES is chartered to perform both Shuttle and ISS EVA task thermal analysis. The shuttle flight analysis covers flight specific shuttle based EVA tasks, including scheduled, unscheduled and contingency tasks documented in the FRD. The ISS analysis covers scheduled, unscheduled and contingency assembly tasks documented in the IDRD. For both, the preliminary analyses are complete at approximately L/I -6 to 10 months, and the final analyses are complete at L/I 1 month. The preliminary analyses use low fidelity models, and the final analyses use high fidelity models.
For increment ISS unscheduled maintenance and contingency tasks, LMES has developed an increment EVA database to support quick turnaround analysis. The database consists of low fidelity models of ISS surface temperatures and EMU thermal environments. Once a task is scheduled, Mr. Bue can use the database to provide a thermal analysis. If there is time and if required, a higher fidelity model can be incorporated to provide a more accurate analysis.
Ms. Patrick briefly recounted the Boeing thermal analysis information provided at the August 22 EVA AIT (see 8/22 EVA AIT minutes for details). Mr. Bue highlighted the assumptions used in the LMES analysis that are different than the Boeing analysis. Mr. Bue uses a solar constant that is approximately the average of the summer and winter numbers. This is not a significant factor in the results however. Mr. Bue also uses the Beginning of Life (BOL) properties for the ISS hardware until the element has been on-orbit for 2 years, at which point he switches to the End of Life (EOL) properties for that element. Boeing analysis assumes EOL properties since their job is to certify the element meets requirements throughout its life on-orbit. Additionally, Mr. Bue does not assume a beta angle or attitude for his analysis, since these are known quantities at the time of the analysis. Mr. Bue noted that if an EVA moves more than 4 days from the date assumed for the analysis, the guideline is to redo the analysis. This is because the beta angle changes enough after that time to change the results and recommendations.
Mr. Bue explained that his previous analysis assumptions were that there is only incidental contact with all parts of the EMU except the gloves and the boots. He flagged worksite surfaces over 250°
F as potential areas of concern for mission assurance. Under this guideline, 3A was the first flight where "hot" tasks have been identified (scheduled PMA 3 umbilical mating, and unscheduled MDM R&R). Based on the new concerns with extended EMU contact for tasks, Mr. Bue will work with MOD to flag tasks requiring more than incidental contact and will constrain those tasks to contact at temperatures less than 150°
F.
Significant discussion not included in the presentation material:
The EVA AIT discussed the method by which MOD requests the near real time analysis for the increment based unscheduled tasks should the need arise to perform those tasks. MOD noted that this has happened on previous shuttle flights and the analysis has been requested through a MER Chit. MOD agreed to look into how the process is documented and to ensure that the EVA console knows to request the analysis for the increment tasks.
The EVA AIT discussed the process by which the EVA tasks that require greater than incidental contact will be assessed for the thermal environment. EVA AIT members agreed that a standard milestone schedule should be established where MOD reports on the flight tasks that require extended contact. This should be in time to support Mr. Bues analysis schedule. MOD felt that perhaps the EVA baseline and mid-flow reviews would be a good time, but wanted to investigate further before committing to that schedule. The EVA AIT also agreed that once Mr. Bue receives the tasks, there should be a milestone report for him to provide feedback on the results. The EVA AIT thought that adding a line item to the EVA CoFR was probably the right way to provide the appropriate visibility to the thermal concerns. Ms. Patrick will investigate adding the appropriate information to the EVA CoFR.
Finally, the EVA AIT discussed addressing the thermal concerns for the near term flights. MOD agreed that within one week, they could assess the 3A tasks identified to determine if they require more than incidental contact protection. Mr. Bue agreed to provide thermal analyses for 4A 6A flights within one week, and MOD agreed to assess any tasks in the hot areas within one month.
Action Item Closure: AI-537 was CLOSED
Actionee: DX32/Mary Fitts
Due Date: October 10, 2000
Method for Closure: Report to EVA AIT
Actionee: DX32/Bob Adams, Chris Looper
Due Date: October 10, 2000
Method for Closure: Present to EVA AIT
Action 544: Provide 3A 6A flight specific thermal analyses to MOD for task comparison
Actionee: LMES/Grant Bue (3A provided ASAP)
Due Date: September 19, 2000
Method for Closure: Report to EVA AIT
Actionee: DX32/Bob Adams, Chris Looper
Due Date: October 10, 2000
Method for Closure: Present to EVA AIT
3. EMU Certification status, Test Plan, Objectives HSMS/Vicky Margiott,
Ms. Margiott provided information on the EMU capabilities, certification status and concerns with exceeding the current certification. Ms. Margiott noted the current TMG incidental contact limit is 320°
F for brush (30 sec at .1 psi) and bump (3 sec at 1 psi) loads. Ms Margiott explained that there is no requirement/certification for contact for the visors or the Display and Controls Module (DCM). The concerns with exceeding the TMG certification on the hot side have been documented in previous EVA AIT discussions (July 18, August 22). Ms. Margiott also reported that previous testing for the TMG beyond the brush and bump loads indicate that damage occurs at ~5 minutes at a temperature of 200°
F.
The EVA AIT also discussed TMG limits on the cold side. There has been no testing on the suit in the cold environment, even for brush and bump contact. Ms. Margiott reported that the max continuous use temperature for the bladder is -20°
F, which is the only known temperature limit. There has been no work to determine the
The limits for/concerns with the visor are as follows:
- Sun visor: max continuous use temperature is 340°
F - Protective visor: max continuous use temperature is 200°
F - Pressure bubble: max continuous use temperature is 160°
F
These limits result in radiation heating concerns. The limit for radiation is 300°
F at 12" distance from a hot surface for 15 minutes, or 270°
F at 12" for unlimited exposure, with the sun visor up. With the visor down, the limit is 325°
F at 6" distance for unlimited exposure. These limits are both documented in flight rules and are included in the LMES thermal analysis considerations.
In addition, the visors are not certified for any contact, regardless of the temperature. The original design requirement assumed that the crew would see something in the path and therefore avoid physical contact. The EVA AIT concluded that there is no requirement to consider extended contact for the visor, however it is not unreasonable to assume that inadvertent contact will occur.
The limits for/concerns with the DCM are as follows:
Extended contact at cold temperatures could cause the Item 321 temperature control valve to freeze if the suit is in LCVG bypass, since there is stagnant water at that point. The EVA AIT noted that the presence of the MMWS somewhat mitigates this risk. The DCM does have a requirement for contact (the entire suit, except the visor, is required to meet inadvertent contact at 2 ft/sec).
Significant discussion not included in the presentation material:
The EVA AIT discussed the guidelines that should be used at this time to evaluate the EVA tasks that require extended contact. The EVA AIT decided that the visor and the DCM, while a consideration, are not really the drivers for resolution of contact concerns for the EMU. Ms. Margiott proposed that the continuous use temperature for the bladder should be used, with some margin added to ensure safety. Ms. Margiott proposed a range from -10°
F to +150°
F. This is probably conservative, particularly on the cold side, but without any other information to ensure that any broader assumptions are safe, this is the only information the EVA AIT could go by at this time. The thermal team noted that this range is severely limiting for the ISS thermal environment. The low temperature will be likely be exceeded during night passes and the high temperature will be exceeded during daylight. The thermal team agreed to evaluate this temperature range to try to provide a quantitative assessment of how often the range will be violated on how much of the ISS, and also agreed to try to determine a range that would cover most of the ISS most of the time. This information will be used both to better quantify whether there is a hardware issue and to establish the limits we will be trying to attain through an EMU test and certification program.
The EVA AIT discussed the testing that could be performed to determine actual limits for EMU contact. One of the questions is what force/load to assume for extended contact. A 1 psi load is extremely high for any significant size area to contact. In previous tests for the inadvertent contact and space welding cases, test subjects had difficulty sustaining the 10-20lbs force required to maintain a 1 psi load. The EVA AIT determined that one way to establish a good set of load cases would be to take some rudimentary force measurements in the NBL, using typical operational scenarios. XA/Brian Johnson agreed to develop a test plan for the proposed NBL testing and the follow on EMU certification thermal testing.
Decision: The EVA AIT concluded that the only known temperature range that could be used for extended EMU contact is based on the bladder continuous use temperature. This temperature will be used for EVA task/thermal analysis until additional testing or analysis opens that envelope.
Action Item Closure: AI-538 was CLOSED
Actionee: ES/Marie Kowal, B-Hou/Ryne Baker
Due Date: October 10, 2000
Method for Closure: Present to EVA AIT
Actionee: XA/Brian Johnson
Due Date: October 10, 2000
Method for Closure: Report to EVA AIT
4. Planned uses for Orlan on US Segment DX32/Randy McDaniel, Chris Looper
Mr. Looper presented for Mr. McDaniel. Mr. Looper presented data that showed the prime suit for each ISS increment through Increment 7. The Orlan is deemed prime for increments with increment scheduled RS assembly and the EMU is prime for increments with increment scheduled USOS assembly. Mr. Looper noted that the crew is trained on use of either suit, however they will be trained more extensively on the prime suit. The operations ground rule is that the EMU will be used on the USOS and the Orlan will be used on the RS. Tasks are scheduled for the increment crew on only one segment or the other, and the limited training on the other suit covers unscheduled maintenance and contingency tasks.
Significant discussion not included in the presentation material:
The EVA AIT discussed the thermal situation for the Orlan on the RS segment. EC5/Vince Witt noted that while there is some information on the Orlan suit capabilities, there is very little information on the thermal environment for the RS. After the EMU discussion, Mr. Witt agreed that the same issues should be addressed with the Russians, and he will both follow the EMU thermal issue development and begin developing discussion plans with the Russian team members.
Action Item Closure: AI-539 was CLOSED
Action 548: Develop discussion plans for addressing EVA thermal issues with extended contact for the Orlan with ISS
Actionee: XA/Mike Mankin, EC5/Vince Witt
Due Date: October 10, 2000
Method for Closure: Report to EVA AIT
5. Touch Temperature NCRs previously approved NC5/Edgar Rivera, B-Hou/Joe Thomas
and SRP agreements on touch temperature violations
Mr. Rivera provided a list of the NCRs that addressed touch temperature violations as well as touch temperature violations documented in hazard reports. He also described the agreement at the SRP that for touch temperatures below 320°
F. NCRs are no longer required for hardware up to 320°
F. These are still considered hazards that must be documented in a hazard report with an operational control. MOD has to agree to the operational controls, so the EVA AIT concluded that the agreement is still valid, since MOD wont accept the operational control if it introduces too much risk.
The EVA AIT will use the hardware list to evaluate the tasks associated with that hardware and determine whether they are a risk for extended contact.
Action Item Closure: AI-535 was CLOSED
6. Tracking of Operational Controls and Inclusion DX32/Chris Looper
in Operations documentation and training.
Mr. Looper presented information on MODs process for tracking operations constraints from one flight to the next. The EVA team incorporates constraints, cautions, etc. into the EVA checklist starting at ~L-12 months. The information comes from operations deliverables and NCRs. There are both flight specific and generic sections of the EVA checklist, and the generic section is supposed to account for all of the previous element constraints that apply for on-going operations. It is the next flight leads responsibility to pick up the flight specific constraints from the previous flight and incorporate them in the generic section of the checklist as appropriate. Mr. Looper noted that there is no process outside of the EVA AIT for PIDS exceptions to be incorporated into the operations data if the constraints associated with the PIDS exceptions are not incorporated into the formal operations deliverables. Ms. Patrick agreed that the PIDS exceptions should not be the only source of the constraints they represent, that the developer should document those constraints in OP-01, OP-04, SSODB or a hazard report. However, all agreed that it is a good check for MOD to review PIDS exceptions associated with an element to ensure the data is included. Ms. Patrick agreed to send the EVA AIT decisions matrix to MOD and the crew office, which documents all the PIDS exceptions, NCRs and waivers evaluated and approved by the EVA AIT since October 1997.
Action Item Closure: AI-536 was CLOSED
7. Summary XA/Nancy Patrick, All
Ms. Patrick reviewed the actions assigned and conclusions reached, and summarized the overall direction. In the near term, assembly flight tasks will be evaluated to determine if they require extended contact outside of the thermal range that is known to be safe. In the long term, EMU testing and delta certification will identify extended contact limits that will hopefully be broader than the existing limits. Additionally, the ISS thermal environment will be better characterized and will be used to drive the testing parameters and objectives. Ms. Patrick proposed that the same group meet again on October 3 to review the results of the actions and the status of the thermal issue resolution.
8. Upcoming Events/Future Agenda Review XA/Nancy Patrick, All
Ms. Patrick reviewed the preliminary EVA AIT agenda for September 26, 2000. Presenters are requested to confirm agenda topics by COB Thursday, September 21.