Status Report

EVA AIT Minutes 1 August 2000

By SpaceRef Editor
August 1, 2000
Filed under

To: Distribution

From: XA/Nancy J. Patrick

Subject: Minutes for August 1, 2000 EVA AIT

The EVA AIT met at the Johnson Space Center on August 1, 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, ER/Engineering Robotics, OB/ISS Vehicle Office, OC/ISS Operations Office and Boeing-Houston (EVA, Launch Package, Operations and Safety) were present. Representatives from the Kennedy Space Center, Marshall Space Flight 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 August 15, 2000:

BCP-EVCS-001 through BCP-EVCS-027: Various cleanup exceptions to P4 PIDS concerning verification

The Following Decision Packages were dispositioned (distributed June 27, open work from July 18)):

ESA-Cup001: Clearance around EVA Bolts (distributed as tracking number ESA-001)

Open Work from last AIT: XA/Heather Mitchell to confirm with engineering that the clearances provided will accommodate the necessary tools.

Decision: Ms. Mitchell confirmed with EC5/Roger Schwarz that there is sufficient clearance for all the extensions except the 2" extension. MOD and CB confirmed that the 2" extension is not required for the tasks. The PIDS exception was approved.

PG1-S0-EV&CS-27-05: S0 EVA Label operational name character height for Luminaire ORUs

Open Work from last AIT: PG1/Phil Peterson to explain whether the font size indicated in the exception is the largest that it can be and why.

Decision: CB/Fernando Ramos reviewed the data on the label and determined that it is acceptable provided the label is placed in a visible location. The EVA AIT approved the PIDS exception based on this assumption.

The Following Decision Package was dispositioned (distributed via Email July 26):

PG3-AL-01-2000: Airlock Anthropometric Requirements

Decision: The EVA AIT approved this PIDS exception

The Following Action Items were reviewed:

This action remains open and will be addressed again on September 12. Ms. Jochim has received no response from repeated inquiries. Ms. Patrick and Ms. Jochim will bring up the matter with the MSS lead for the ISSPO.

AI-494: This action remains open and will be addressed again on August 15. Mr. Ramon reported that all of the inputs are in and he is now compiling them into a single list.

AI-504: This action remains open for Mr. Price, Mr. Boller and Mr. Ramon and will be addressed again on August 15. Mr. Looper reported that he had the list of compatible WIFs for P3/S3, P4/S4 and P6/S6. Mr. Looper reported the only other known WIF sockets that are OTD compatible are: 1 on each CETA cart and 2 on PMA1. Mr. Price will look into whether PMAs 2 and 3 have similar compatible WIFs. Mr. Boller agreed to provide the appropriate nomenclature for the P4/S4 and P6/S6 WIFs. Mr. Ramon agreed to look into documenting the known locations in the SSODB. This will provide Boeing authorization for the data and a data location authorized for operations.

AI-505: This action remains open and will be addressed again on August 15. Mr. LeStourgeon did not provide and updated status.

AI-510: This action remains open and will be addressed again on August 29. Mr. Carlton did not provide an updated status.

AI-511: This action remains open and will be addressed again on August 29. Ms. Patrick has not coordinated the PIDS exception list with LPMs or element managers.

AI-512: This action was CLOSED. The test was conducted and proposed operational procedures have been demonstrated and agreed to.

AI-513: This action remains open and will be addressed again on August 15. PG1 is confident in the predicted response to inadvertent release however they will provide data supporting their prediction to close the action.

AI-514: This action remains open and will be addressed again on August 15. Mr. Boller has updated the PG2 line items and Mr. Price will review and provide inputs to the PG1 line items.

AI-515: This action was CLOSED. Mr. Looper reported that MOD had updated the 3A and 5A.1 fit check matrices and they were ready for XA to present for re-baselining. Ms. Patrick noted that addition of the QD bale drive tools to the tools column of the matrix does not require re-baselining since this column is not configuration managed by the EVA AIT.

AI-521: This action remains open and will be addressed again on August 15. Mr. Harless did not provide an updated status.

2. TUS cable Deployment Demonstration Results PG1/Todd Nordvedt

EA/Tom Farrell

This was a follow-up to the May 23 EVA AIT discussion. Mr. Nordvedt presented the results of the two demonstrations of the new TUS cable deployment procedure. The first demonstration was performed at Huntington Beach on June 23 using qualification hardware. The second demonstration was performed at KSC on July 24 on the flight unit. Both demos included representatives from the Astronaut office and Huntington Beach. MOD and Engineering participated in the demo at Huntington Beach. The procedure evaluated was having EV1 pull 2-3 feet of the cable at a time out of the TUS reel while based on the SSRMS with the brakes on. EV2 monitors the EVA drive of the TUS reel. After each 2-3 feet of cable is extracted, EV1 slowly relaxes cable tension until the control arm reaches its limit (approximately 12 inches of cable is retracted). The SSRMS is then repositioned for the next extraction.

The first demo resulted in the following commends and recommendations from participants:

  1. Position EV2 at the TUS reel cable exit point to tend the cable

  2. Only use EVA drive to relax tension for freeing cable and cable cutter fitting from the launch position

  3. Safety tether reel may be utilized as an alternate to the SSRMS if required

  4. Wire ties should be used to restrain the TUS pigtails during the cable deploy

  5. TUS cable can be installed into cable guides either during or after full cable deployment, however after full deployment is preferred.

  6. Forces required to move control arm to hard stop, overcome brake and pass through a cable guide at a significant angle are all acceptable.

  7. No changes to TUS reel design are required.

The second demo resulted in no PRs or squawks against the deployment procedure (1 PR and 1 squawk were documented on unrelated hardware). Both demos resulted in successful cable deployment using the proposed procedure. There is forward work to determine the effects of inadvertent release and to determine the allowed cable angle relative to the exit point. Cable twist is unacceptable however positioning EV2 at the exit point, monitoring the cable, is thought to provide sufficient oversight to avoid problems. The crew office confirmed that there are sufficient visible indications of the cable twist to monitor it adequately. There is additional forward work to perform the SSRMS joint angle analysis and update the worksite analysis and OP-01 inputs, however the forward work does not require oversight from the EVA AIT and does not preclude approval of the TUS cable deployment procedure and EVA AIT concurrence with the design (EVA AIT noted that formal NASA acceptance of the hardware is through the Hardware Acceptance Team led by engineering).

Decision: The EVA AIT concurred with the revised TUS deployment procedure and with the TUS cable reel design.

Action Item Closure: AI-512 was closed, AI-513 remains open

3. UMA Interference during CAS Deployment PG1/Roger Larsen

on P3/S3

Mr. Larsen described the interference between the UMA and the S3/P3 segment during CAS deployment. This interference was discovered during S3/P3 NBL testing and confirmed that the flight hardware has the same interference. The interference is between the UMA shroud, internal housing and EVA handle against the S3/P3 primary longeron and 2 secondary clevis brackets used to support the CAS platform in both the stowed and deployed configuration. There are 3 CAS (UCCAS) platforms on P3 to support unpressurized logistics carriers and 4 CAS (PAS) platforms on S3 to support attached payload carriers. Four options have been identified to resolve the issue. The first two involve operational workarounds with no change to hardware design and the last two involve a mix of operational workarounds and hardware redesign. The first option requires removing the UMA before or during CAS deployment and re-installing after deployment. The second option requires launching the UMAs on a separate carrier (possibly on a later flight) and installing them after CAS deployment. The third option requires launching the UMA on another location on P3 and S3 and installing them after deployment. The fourth option requires redesign of the CAS hardware to allow launching the UMAs in place with no interference during deployment.

Significant discussion not included in the presentation material:

The EVA AIT requested information about the when the CAS’ are deployed. They cannot be deployed until after ISS has transitioned to LVLH attitude. This is because the XPOP shrouds cannot be removed until that time, and the shrouds interfere with CAS deployment. This transition occurs after normal External TCS activation, currently planned for stage 12A.1. Further, CAS deployment requires temporarily removing a strut on the element, and there is some concern that as additional elements are installed outboard (S5/P5, S6/P6), there may not be enough structural margin to allow removing that strut. B-HB is assessing CAS deployment with P5 installed. After looking into the assembly sequence, it was clear that for the port side, transition to LVLH does not occur until after P5 is installed anyway, so B-HB has to accommodate CAS deployment with that module installed. Ms. Patrick requested that if additional analysis is in work, that B-HB analyze the operation with P6 installed, so that the most flexibility on CAS deployment is afforded the operations community. This is anticipation of the requirement to install the UMA after CAS deploy.

The EVA AIT then discussed the proposed operational workarounds to the issue. Since the redesign options involve changes to structural members of elements soon to be delivered, the EVA AIT acknowledged that the operations workaround options are likely to be required unless they are not at all feasible. The Astronaut office noted that, with respect to operational feasibility, re-installation of a UMA after CAS deployment is the same task as a UMA remove and replace which has been demonstrated in NBL testing. Removing the UMA prior to CAS deployment is questionable, however, since access to the UMA is very different with the CAS stowed. B-HB/Dave Anderson has been looking at the task in Unigraphics analysis and felt that while it doesn’t meet the letter of the law for EVA requirements, it looks feasible. Mr. Anderson agreed to send data to the crew office for evaluation. Additionally, MOD agreed to perform a timeline analysis of options 1 and 2, determining the additional EVA time required and whether that fits into the existing timelines. MOD will use the current requirement to deploy the CAS after transition to LVLH attitude and before P6/S6 is installed as the constraint for incorporating the additional EVA.

There was a brief discussion of whether removing and re-installing the UMAs on-orbit nullifies the certification of the system. Since these are considered ORUs, the EVA AIT concluded that the ISSPO has to allow for this regardless of the interference issue, so this was not considered a driver to the issue resolution.

Ms. Patrick also questioned whether this interference was identified during B-HB Worksite analysis. Mr. Anderson noted that it wasn’t due to errors by several participants in the process. The B-HB analysis checked for interference in the stowed position and in the deployed position, but did not check for interference during the deployment sweep. This was also true for other deployable mechanisms. B-HB has since checked the remainder of their deployable mechanisms and has not found any similar interferences. This has also been found to be true in NBL testing.

The topic will be scheduled again for August 15 review to support program discussions on how to proceed with the issue.

Action 524: Provide Unigraphics views of UMA removal with CAS stowed for all CAS platforms on S3/P3 to support evaluation of UMA removal by NASA.

Actionee: PG1/Dave Anderson

Due Date: August 8, 2000

Method for Closure: Report to EVA AIT

Action 525: Provide timeline and task analysis of adding requirement to install UMA after deployment, after transition to LVLH and before S6/P6 installation. Indicate a preference, if any, of option 1 (R&R UMA around CAS deployment) or option 2 (launch UMA separately and install after CAS deployment.

Actionee: DX32/Chris Looper, CB/Fernando Ramos

Due Date: August 15, 2000

Method for Closure: Present to EVA AIT.

4. Follow-up to SSCN 3730 Discussions (addition of XA/Nancy Patrick, all

S5/P5 PDGFs, possible MT/CETA Rail deletion)

Ms. Patrick reviewed the events since the 7/18 EVA AIT discussion concerning the addition of PDGFs to P5/S5. On July 27, the VSIP reviewed the results received to date for the SSCN 3730 assessments, and agreed that retaining the MT/CETA rails is required. However the VSIP did not see any reason to continue pursuing addition of PDGFs (or anything beyond the current baseline) if the rails are required and there are reasonable solutions to the issues with the on-orbit installed rails. The VSIP asked for final arguments to the contrary within 2 weeks (August 10). Ms. Patrick requested that the EVA AIT look at two possible scenarios to determine if the current baseline (no PDGFs, rails delivered 1-1/2 to 2 years after P6 relocated outboard) is broken:

  1. Inability to install a new ORU before it exceeds its thermal limits due to EVA overhead without the rails for an ORU, for an ORU which must be protected during this time

  2. Inability to install a large ORU without any robotic support, for an ORU which must be protected during this time

Ms. Patrick noted that a good portion of the above work has already been done in support of the previous actions on this topic. The first scenario timeline was developed for the rails vs. PDGF discussion from the time the ORU is located at P3/S3 and is only lacking the ORU unpowered time. The second scenario previously assumed SSRMS support from a PDGF in the change out, and only requires a determination of whether certain ORUs can be transported from P3/S3 to P6/S6 without any robotic support at all.

Significant discussion not included in the presentation material:

DX32/Chris Looper remarked that while not yet designed, the assumption within the maintenance community is that there will be some form of power supply to ORUs while they are transported on the MBS. This means that the EVA timelines previously presented for the robot-failed case can be used to determine the time without power. Mr. Looper agreed to re-work the timeline to minimize the time without power, but this could potentially increase the number of EVA sorties so that the task can be arranged to allow the ORU disconnection at the beginning of an EVA. Mr. Looper agreed to provide an overview timeline for the days leading up to the ORU unpowered EVA sortie, and a detailed timeline of the ORU unpowered EVA sortie as revised. Mr. Robbins also agreed to provide a list of ORUs that cannot be changed out without robotic support, based on the list of PV Module ORUs previously provided by PG2/Curt Carlton.

OC/Bill Robbins, the ISS Logistics and Maintenance lead, discussed several concerns with the lack of rails/lack of PDGFs baseline. Mr. Robbins is concerned with the overall maintenance demand during the time in question. The failure rate of ORUs, coupled with the backlog of maintenance tasks, results in the EVA demand exceeding the ISS capability. Additional EVA overhead to support P6 maintenance further complicates the issue. Ms. Patrick requested that Mr. Robbins consult with OC/Ron Torcivia to add this indirect issue to the story to be presented to the VSIP. Mr. Robbins also noted that the ORU unpowered time is also a concern for the ORU to be replaced. Keeping the failed ORU powered is critical to refurbishing it once it is returned. Since the program maintenance plan does not include procuring new ORUs, and there are not a lot of spare ORUs, if the failed ORU suffers severe damage from being unpowered, this could create an ORU shortfall from which the program might not be able to recover. Ms. Patrick suggested that the EVA timelines consider minimizing the unpowered time for the new ORU as the top priority, and the failed ORU time would then be available from the resulting timeline. The integrated issue resolution would then include both concerns.

The EVA AIT then discussed the additional work required after both the EVA actions were complete (list of ORUs which cannot be changed out and the EVA timeline impacts, including the ORU unpowered times). Ms. Patrick stated that these inputs will be provided to Mr. Torcivia, who will be responsible for determining whether the ORU unpowered times exceed the ORU capabilities, and whether the ORUs which cannot be maintained are critical. Mr. Robbins currently has a list of all the critical ORUs during this timeframe, so the EVA AIT can provide some of the conclusions. Mr. Torcivia will have to provide the final answer, however, based on the absolute requirements of the PV modules.

Finally, EVA AIT members also suggested developing workarounds for the expected issues that result from the above assessments. Some have been previously identified, and include additional EVA cranes pre-positioned outboard of the SARJ to minimize crane repositioning, or longer cranes to minimize hand-offs. Other possibilities include utilizing both the orbiter and the ISS airlocks and crews to accomplish the change outs as quickly as possible to minimize ORU unpowered times. Ms. Patrick requested all members of the EVA AIT bring forward any other possible solutions.

Action 526: Develop EVA timeline for ORU change out of PV module ORUs without robotic support. Include detailed timelines for the ORU unpowered times, and overview timelines for the time leading up to and following the ORU unpowered detailed timeline that pertain to the PV module maintenance. Also determine the ORUs that cannot be replaced without robotic support.

Actionee: DX32/Chris Looper

Due Date: August 8, 2000

Method for Closure: Present to EVA AIT


5. PDGF Connector Keying Waiver OM/Diep Nguyen

They was no presentation material for this topic.

Prior to the EVA AIT, the ISSPO MSS IPT requested evaluation of a proposed waiver to requirements to key connectors for the PDGF. The hardware has been built and the connectors are in connector "blocks" and not keyed. The P and J numbers are labeled uniquely on either side of the interface so that if they are mated in accordance with the labels, they will be connected correctly. The crew office has reviewed the connector labels and confirmed that they are sufficient for EVA use. The EVA AIT concluded that, assuming the waiver requests an exception to the keying requirement, with the labels as justification, it will be approved by the EVA AIT (the waiver in its final form was not available for the EVA AIT). It should be noted that the EVA AIT cannot guarantee that the connectors will not be mated incorrectly, but nothing short of keying can guarantee that, and the proposed labeling is consistent with other equally critical operations which rely on the crew executing the operation correctly. The impact of mating the connectors incorrectly is most likely bent pins in the connectors, however the electrical design precludes further hardware damage.

Decision: The EVA AIT approved the concept for the PDGF waiver to the connector-keying requirement.

6. EVA standard ICD status follow-up discussion LMES/S. Rogge, XA/N. Patrick, PG1, PG2, PG3, B-Hou,

There was no presentation material for this topic. Mr. Rogge and Ms. Patrick reviewed the known status of the open ICD PIRNs. Specifically, the following PIRN status and open issues were discussed:

61C: Ms. Patrick reported that this PIRN has been signed and the PIRN is closed.

65A: PG1, XA — No one present knew the status of SSCN 3731

67: EC5, LMES — No one present knew the status

70: LMES, PG2 — This PIRN was approved by PG2 and therefore Ms. Patrick agreed to sign and forward to the program office.

71: LMES — Mr. Rogge reported that the PIRN revision has been informally submitted to PG1 and LMES is awaiting a response before formal submittal to the program.

Ms. Patrick will attempt to get an updated status from EC5 for the PIRNs that are still open prior to the next EVA AIT. EC5 did not support the EVA AIT for this topic

7. Upcoming Events/Future Agenda Review XA/Nancy Patrick, All 4:30

Ms. Patrick reviewed the preliminary EVA AIT agenda for August 15, 2000. Presenters are requested to confirm agenda topics by COB Thursday, August 10, 2000.

The Following item was deferred prior to the EVA AIT at the request of the presenter:

Cupola Joint Program Review Debrief XA/Heather Mitchell

Present major EVA issues and recommendations from the Cupola JPR. EVA AIT members concur with recommendations for resolution and design provided at the JPR.

Decision Required: EVA AIT concurrence with JPR recommendations

Required Attendees: XA, Boeing-Houston, DX32, CB, NC, KSC/SSHIO, ESA

The Following item was deferred until August 15 for lack of time:

Status of assessment EVR based EVA tasks B-Hou/Lou Ramon

Provide update from March 14 EVA AIT presentation on assessment of EVR based EVA tasks for which no handhold is provided to react the force. Update status on task assessments still open as of March 14, 2000 (radiator end cinch pin task on flight 9A, and the dummy panel removal from the S0/Node 3 tray on flight 16A).

Decision Required: EVA AIT concurrence that tasks are acceptable and resolution plan for tasks that are found to be unacceptable.

Required Attendees: XA, Boeing-Houston, DX32, CB, NC, KSC/SSHIO, PGs, SLP, Node 2/3, ESA, NASDA, CSA

SpaceRef staff editor.