Status Report

Minutes for July 3, 2001 EVA AIT

By SpaceRef Editor
July 3, 2001
Filed under , ,

To: Distribution

From: XA/Nancy J. Patrick

Subject: Minutes for July 3, 2001 EVA AIT

The EVA AIT met at the Johnson Space Center on July 3, 2001. Boeing/David Read and XA/Nancy Patrick co-chaired the meeting. Representatives from CB/Flight Crew Operations, XA/EVA Project Office, NT/Flight Systems Safety and Mission Assurance, DX32/EVA Systems/Mission Operations, OB/ISS Vehicle Office, OZ/ISS Payloads Office and Boeing-Houston (EVA and Safety) were present. Representatives from the Boeing Development Centers supported by telecon. Copies of presentations can be obtained from XA/Bill Rollins, Building 1, room 661, (281) 483-1416.

1. Introduction/AI Review Boeing/Dave Read

XA/Nancy Patrick

The Following Decision Packages were reviewed (distributed June 19, 2001):

PG1-P3-2001-1: SARJ Launch Restraint and EVA Bolt Break Torque Requirement

This PIDS exception was deferred until July 24. MOD requested additional time to consider the ramifications of deleting some of the break torque test requirements. Ms. Patrick asked PG1/Roger Larsen to review the exception with XA/Beth Stubbings and Ed Mohr in the next couple of weeks.

The Following Action Items were reviewed:

AI-594: This action remains open and will be addressed again on July 24. The action was officially transferred to the crew and MOD. CB/Joe Tanner reported that he had not yet reviewed the data on S3 and P3 attachment.

AI-595: This action was CLOSED for EVA AIT consideration. The S0/8A EVA IPT has accepted the action. ES/Trevor Kott has surfaced some concerns with the Struc and Mechanisms input from Huntington Beach. XA/Heather Mitchell will work to resolve the issue.

AI-606: This action was CLOSED. XA/Greg LeStourgeon has authorized funding to develop a cost ROM and schedule from EC and LMES. EC/Joe Chambliss will initiate the CR when the ROM is available. Mr. Chambliss reported that they are looking at providing the bag for launch in the MPLM on flight ULF-1. The XA Hardware Group has taken over development responsibility for development and will work with Mr. Chambliss to meet the schedule required. See minutes below for additional information.

AI-613: This action was CLOSED. Mr. Bonuan reported that one of the bolts on each of the Lab attach plates (4 total) does not have the clearance required for use of the PGT alone. This issue will be worked through the S0/8A EVA IPT.

AI-614: This action was CLOSED. Mr. Chambliss reported that he had worked with the ULF-1 team to get the bag manifested and had presented to the CWG to get acceptance of the bag for the airlock. Once a ROM is provided by XA/EC, Mr. Chambliss will develop the CR to get funding. See minutes below for additional information

AI-615: This action was CLOSED. Ms. Patrick provided her comments; the remainder will be discussed in a splinter session during the stowage bag concept review. See minutes below for additional information.

2. Early Ammonia Servicer (EAS) Return on Spacehab/Richard Meyer

Integrated Cargo Carrier (ICC)

Mr. Meyer presented the concerns with the EAS return scenario on ISS flight 13A.1. The EAS must be returned prior to P6 relocation because it interferes with the MT translation corridor while P6 is being moved. On 13A.1, the cargo bay configuration consists of the Integrated Cargo Carrier (ICC), a Spacehab module and the S5 segment, in order from front to aft. The EAS is bolted to the ICC for return (bolts are accessed from underneath the ICC. The problem is that the Spacehab tunnel runs underneath the ICC (since the ICC is fore of the Spacehab) and therefore access underneath the ICC does not meet EVA worksite volume requirements. The ICC/EAS configuration is the same on 7A.1 for EAS deploy, however there is no Spacehab so the access is considerably better.

NBL testing was considered for the 13A.1 configuration, however it was rejected because the access looked so poor that it was considered a waste of NBL time to even attempt this operation. Since those discussions, however, Spacehab has reassessed the configuration and was able to move the ICC pallet 8 inches further aft (closer to the Spacehab module but further from the tunnel support struts). This repositioning provides approximately 4 additional inches to the translation volume than what was previously reported. They are currently reporting a translation clearance of 37.5" between the ICC and the tunnel struts (34.5" with existing handrails installed, however handrail locations are optional and very flexible). At the worksite, a 43" diameter exists for a working volume. This will be tight because the PGT, socket and torque multiplier are planned to be used to install the EAS.

Significant discussion not included in the presentation material:

Boeing/Jeff Heitzman reported that for other considerations, the launch package team is evaluating a new configuration of the payload bay that will resolve the clearance problem entirely. The team is looking at moving the Spacehab module to the most forward location in the payload bay, trailed by the S5 element and then the ICC. In this configuration, the Spacehab tunnel is no longer under the ICC and the clearance problem is resolved.

Another concern arose during the discussion. Spacehab personnel indicated that the torque multiplier is required to provide sufficient torque for installing the EAS bolts, and the right angle drive was not desired because it would not provide the accuracy required (the right angle drive was suggested as a way to alleviate some of the work volume concerns). Ms. Patrick asked what torque and accuracy are required and Mr. Meyer reported that 46.4 ft-lbs is the torque required, with an accuracy required, he thought, of ±10%. Ms. Patrick noted that the PGT accuracy alone is ±10% and adding the torque multiplier would decrease the accuracy somewhat. If 10% accuracy is truly required, the torque wrench might be required and operational constraints would probably be required on when the torque wrench could be used.

The EVA AIT concluded that with the additional clearance provided, it is possible to install the EAS on the ICC on flight 13A.1, however NBL testing would definitely be required to conclude that it is reasonably feasible. However the EVA community does not want to run an NBL test if the configuration is changing soon anyway. The time available to test this configuration is in the late August or late September timeframe. Ms. Patrick asked Mr. Heitzman to keep us informed of the status of the assessment, and noted that EVA would be happy to support any discussions on changing the cargo bay configuration.

Decision: The EVA AIT recommended that if the current 13A.1 payload bay configuration (ICC/Spacehab module/S5) is maintained, NBL testing is required to determine whether installing the EAS on the ICC is feasible. With the currently presented analysis, enough clearance is shown to make it worthwhile for NBL testing.

3. Vent Tool Stowage Container (VTSC) Status EC/Joe Chambliss, Gary Nickel

XA/Greg LeStourgeon, CB, DX32

Mr. Chambliss – present status of funding and development plans for stowage container. Report progress on manifesting. Mr. LeStourgeon and Mr. Nickel – report schedule for concept review (to be scheduled after funding approved). CB, DX32, XA provide comments to draft requirements provided on 5/29.

Mr. Chambliss reported that he has been working with the ULF-1 team to secure manifesting and EVA time for delivering and installing the VTSC. To make bench review for stowing the VTSC in the MPLM, the VTSC must be delivered for bench review in April, 2002. Mr. Chambliss also reported that he presented to the Configuration Working Group and no major issues have been identified. One question is if the VTSC will be attached to trunnion pins or handrails (handrails preferred for VTSC design simplicity). The CWG was concerned whether use of the handrails is acceptable. The EVA AIT discussed use of the handrails and concluded that, from an EVA perspective, using the handrails is acceptable. Structures analysts will have to approve use of them based on the loads estimated and what the handrails are attached to. The specific handrails will have to be identified during the design process.

Mr. LeStourgeon and Mr. Nickel reported on the schedule and cost status for delivering the bag. Mr. LeStourgeon reported that the tools panel and EHB approved a CR providing funding to develop a ROM and schedule for ISS CR purposes. The preliminary schedule indicates a minimum 24-week development from preliminary design/concept review to delivery. This schedule indicates that development should begin no later than October, 2001 to meet the ULF-1 integration schedule. The schedule and ROM will be complete by the end of next week. At that point, Mr. Chambliss will take the lead in developing an ISS CR to secure funding.

The EVA AIT concluded that the hardware development process will address the remainder of the VTSC development process, and no further EVA AIT discussions are required. The EVA AIT noted that ISS Program participation from TCS and Structures, as a minimum is required during the development process. Mr. Chambliss agreed to provide a comprehensive list of ISSPO participants for reviewing the VTSC design. Mr. Nickel requested hi fidelity (in the way of volumetric characteristics) vent tool mockups to address volume requirements for the VTSC. DX32/Chris Looper indicated that NBL mockups are available for some of the tools, and DX can initiate development of the rest whenever required. He agreed to work with Mr. Nickel to initiate mockup development. In the mean time, the flight tools can be used, if required. Boeing/Mike Melgares is the point of contact for getting those tools. These questions and actions will be addressed during the standard hardware development process.

The EVA AIT requested the status of the 1" ammonia QD used on flight 5A. Mr. Chambliss stated that the tool was still usable, although it had exceeded its certification requirements in its current location on Z1. Ms. Patrick stated that if the tool is no longer certified it couldn’t be used by an EVA crewmember. Mr. Chambliss agreed to pursue re-certifying the tool to its current environment if it is to be considered for use by an EVA crewmember.

Decision: The EVA AIT concluded that no further EVA AIT discussions are required for development of the Vent Tools Stowage Container. The cost and schedule work is far enough along that the standard GFE hardware development process will cover remaining issues.

Action Item Closure: AI-606, 615 were Closed

Action 620: Determine whether 1" ammonia tool stowed on Z1 during flight 5A is still certified for EVA use for venting.

Actionee: EC/Joe Chambliss

Due Date: September 18, 2001

Method for Closure: Report to EVA AIT

4. EVA ICD PIRN 79 (Torque Wrench) Resolution LMES/Ivan Cavenall, OB/Brandy Cox and EVA Standard ICD Status XA/Greg LeStourgeon, B-CP, B-HB, B-Hou

Mr. LeStourgeon reported the status of the torque wrench issues associated with PIRN 79. Mr. LeStourgeon reported that the torque wrench CARD change has been submitted, documenting the torque wrench accuracy with no operational constraints (±20% for all torques except 100ft-lbs), and the accuracy with operational constraints (±10% for torques above 40ft-lbs). The operational constraints documented require that, to keep the torque wrench above 0ºF, it has to be kept in the bag until its used, it has to be used during a day pass, and it has to be used within 3.5 hours after leaving the airlock. The EVA AIT asked that the operational constraints be re-addressed, since they might be very restrictive for some required operations (especially the constraint that it be used within the first 3.5 hours of the start of the EVA). Ms. Patrick requested that Mr. LeStourgeon investigate whether the true constraint is that it be kept above 0ºF and if the ops constraints proposed are what guarantee that is stay above 0ºF for the worst case ISS thermal environment. If this is the case, flight/case specific thermal analysis may show that for other thermal environments, the tool can provide ±10% accuracy under other conditions (particularly later in the EVA), and therefore would be acceptable. Mr. LeStourgeon agreed to look into this and update the CARD to reflect this flexibility if possible. Mr. LeStourgeon reported that the ICD PIRN should be updated within 2 weeks. Everyone present agreed that the updated PIRN is acceptable, given what we know today of torque and torque accuracy required.

Mr. Cavenall provided a status of the other ICD PIRNs. The following status came out of the EVA AIT discussion:

– 81: Adjustable Fuse Tether: All parties had agreed to the PIRN. Ms. Patrick provided the EVA AIT signature

– 82: Drop Proof Tether: All parties had agreed to the PIRN. Ms. Patrick provided the EVA AIT signature

– 83: IAPFR: Submitted on June 4, B-HSV and B-CP have signed. B-HB and B-Hou signatures outstanding, no report on progress

– 84: MWS Modular Gimabal Assembly: Submitted on June 4, B-HSV and B-CP have signed. B-HB and B-Hou signatures outstanding, no report on progress

– 85: Ball Stack Assembly: Submitted on June 4, B-HSV and B-CP have signed. B-HB and B-Hou signatures outstanding, no report on progress

– 86: TM Curved Handrail Assembly: Still in work within LMES, 50% complete, no ECD for submittal

– 87: Wire Tie: All parties had agreed to the PIRN. Ms. Patrick provided the EVA AIT signature

– 88: _ Turn Fastener and Latch Plate: Provided to ICWG for upload, soon to be released for program review

– 89: EVA Connector Brush Assembly: Submitted on June 4, B-HSV and B-CP have signed. B-HB and B-Hou signatures outstanding, no report on progress

– 90: Crew Lock EVA Bag: Released for Program review on 7/2

– 91A: EVA Handrail Update: Provided Revision A to ICWG for upload, soon to be released for program review. Revision A pre-coordinated and should resolve issues with baseline version.

– 92C: CETA Rail Changes: Revisions B and C released since last report. B-CP did not concur with Revision C. Revision in work.

– 93: ORU Tether Assembly: Released for Program review on 7/2

– 94: 3/16" Allen Driver: Still in work within LMES, on hold, no ECD for submittal

– 95: 5/32" Ball End Driver Assembly: Provided to ICWG for upload, soon to be released for program review

Mr. Cavenall reported that the only 5 minor, low priority additions to the ICD remain on the PIRNs required list, and these are still TBD.

PG1 and PG2 reported that they had completed ICD audits and had identified several concerns. The PG1 audit covered the S1 and P1 cargo elements. PG1/Dan Pankratz reported that the only EVA ICD concerns are covered by the PIRNs that are in the system, so if they are approved the issues will be closed. Other EVA related issues with other ICDs will be worked through the 9A/11A EVA IPTs. PG2/Scott Boller reported that B-CP found issues with the Right Angle Drive PIRN (74) that was approved in March. The concern is that not enough information is provided with the cooling requirement if you use the RAD for 5 minutes continuously. B-Hou/Dave Read agreed to look into this concern. The other B-CP issue concerns the torque wrench and once PIRN 79 is approved, this will be resolved.

5. UCCAS/UMA Interference during deployment PG1/Roger Larsen, Ali Mandvi, John Scheerer

Present details on redesign options being evaluated to eliminate the UCCAS/UMA interference during platform deployment. Indicated EVA operations required for each design option. Discuss pros and cons for each option, including design risk, cost and schedule impacts. EVA AIT members discuss concerns with options presented. (VCB action)

Mr. Scheerer and Mr. Mandvi presented the hardware re-design options identified and approved by the Structures and Mechanisms community and the Chief Engineer for JSC/ISS. There are two possible re-design options. The first involves an EVA removable/replaceable clevis and the second involves launching the UMA on a temporary bracket, and relocating it after CAS platform deployment.

The first option has two clevis brackets, one at the launch position for the clevis and one at the on-orbit/platform deployed position. The clevis is released from the launch position by removing the launch bracket’s 4 bolts, which are captive. The on-orbit position bracket is also released at this time, by removing its 4 captive bolts. The platform is then deployed and the on-orbit position bracket is re-installed by driving the 4 captive bolts. A soft dock feature and alignment cues are provided for the on-orbit position bracket. The launch bracket can either be placed in a trash bag or re-installed in its launch location (however no soft dock feature is planned).

The second option deploys the CAS platform per the originally intended procedure, and the UMA would be installed either at the time of platform deployment, or at some time after. The launch plate has to be removed and stowed in a TBD trash receptacle.

Both options have been deemed technically feasible from the design community. B-HB prefers option 1 because of some concerns with option 2. The UMA clearance provided for deployment is very small with this option, and there are concerns that the orientation of the UMA on the plate may result in thermal concerns for the UMA (90º rotation of the UMA presents a side of the UMA that does not have a shroud to the external environment). In addition, substantial design analysis re-work is required to certify launching the UMA in a different location, on a new plate. Finally, the tool clearance for removing the UMA from the plate is very tight. The EVA concerns with option 2 are that you have a plate that you have to find a home for. The only concerns with option 1 are whether the standard 7/16" EVA bolts with locking inserts are sufficient for launching in the launch bracket. This is not thought to be a major concern however. Nut plates would be used if EVA bolts were not acceptable. Nut plates are not desirable from an EVA perspective, but could be accommodated. The additional EVA overhead with either option 1 or option 2 was guessed to be about 30 minutes.

Decision: The EVA AIT concluded that either options 1 or 2 are acceptable for EVA. Option 1 is preferred over option 2, and both are preferred over leaving the design as is and accepting the EVA overhead of removing the UMA prior to deploy and re-installing it after.

6. Upcoming Events/Future Agenda Review XA/Nancy Patrick, All

Ms. Patrick reviewed the preliminary EVA AIT agenda for July 24. Presenters were requested to confirm agenda topics by COB Thursday, July 19. Mr. Boller noted that an MT/CETA rail design review is planned for mid-July, and includes reviewing the MT/CETA corridor issue that is in work through PIRN 92 to the EVA ICD. All interested parties are requested to support the review.

The Following Topic was deferred (no report provided, no estimated reschedule date)

Use of Loctite on EVA Bolts — test results ES/Katherine Davis

Report results of loctite/bolt testing that was scheduled to be complete in spring, 2001. The purpose of the testing is to ensure that use of Loctite is acceptable on EVA bolts as a launch restraint, including EVA force requirements and usability of bolts after initial removal. (Related to action AI-522: "Report on the ISS program plans to resolve questions with the use of Loctite on EVA bolts. Include test plans and proposed completion dates." Closed on 12/12/00)

SpaceRef staff editor.