Status Report

EVA Hardware Board (EHB) Minutes of Meeting April 25, 2001

By SpaceRef Editor

April 25, 2001

Filed under International Space Station, NASA JSC EVA Project Office, US

The EHB met at JSC on April 25, 2001, in Building 1, Room 360, at 1:00 p.m. Representatives from the following organizations participated:

EVA Project Office

Hardware Development

Integration and Operations

Astronaut Office

Engineering Directorate

Crew & Thermal Systems Division

EVA and Spacesuit Systems

EVA, Robotics, & Crew Systems

SR&QA

FCE/EVA

Hamilton Sundstrand Windsor Locks (HSWL) via telecon

Hamilton Sundstrand Management Services

USA

Lockheed

EHB Board members from the following organizations participated:

XA/Chairman, XA/Secretary, XA/Tools and Crew Aids, XA/EMU, XA/Integration and Operations, EA/Engineering, EC5/EVA GFE, MV5/FCE, and NA/SR&QA.

The following items were presented:

Hardware Integration Schedule — XA/Barbara Counts

Changes to the schedule include STS-105 (7A.1) Bench Review 6/12/01; STS-108 (UF1) MPLM JSC Bench Review 6/29/01, and STS-109 (HST-03B) Bench Review 10/12/01.

PRACA Status — NS43/Terry Miller

Twelve FIAR’s are open for EVA hardware and are shown by flight as follows:

STS-104 (7A) 6

STS-105 (7A.1) 10

STS-108 (UF1) 11

One FIAR was reported past due and was statused as follows:

JSCEC0852 — Equipment Hook. Bail Lever sticking (Bail Lever did not perform smoothly and did not stick open).

EC5/Roger Schwarz has the closure paperwork ready for signature. He reported this was an installation issue (springs tangled up). It will close as an assembly error; the rest of the fleet is OK.

One new FIAR was reported:

JSCEC0867 — High Strength Bridge Clamp. Damaged EVA locking pin on High Strength Bridge Clamp Assembly was identified during pre-inspection for vibration test. Pin is sheared off and the back of the knob is damaged at pin mating holes.

This FIAR will be shown as NFC for STS-104 (7A). The issue of what to do with the on-orbit unit was discussed. Adding it to the Limited Life List and "yellow tag — do not use" notices are possibilities. MOD will add a procedure to the checklist to list the hardware as not to be returned on orbiter side wall.

Action 4/25/01-1: Work with MOD to update procedures for HSBC on-orbit unit. Put restrictions on S/N 1004’s use with coordinated comments (caveats) from XA Hardware Group and EC5.

Actionee: XA/Jeff Dutton

Due Date: 5/9/01

The Chairman requested a standard agenda item be added to report any new FIAR’s on on-orbit hardware. XA/Kristin O’Brien will be responsible for this input.

A discussion also ensued concerning the process of maintaining current processing requirements found in CARD documents. This will be the subject of an upcoming audit at USA and will be followed via this forum.

The following STS-105 (7A.1) FIAR’s were statused:

JSCEC0860 — Body Restraint Tether (BRT). BRT will not stay stabilized after tensioning.

EC5/Roger Schwarz reported that the unit is in the processing of being disassembled.

JSCEC0853F — Bayonet Probe. STS-92 (3A) anomaly reported by crewmember. Unsatisfactory fit (tight fit) of bayonet probes to bayonet receptacles.

EC5/Ben Greene presented the following status:

Background: Crewmember from STS-92 (3A) experienced unsatisfactory fit (tight fit) of Bayonet Probes to Bayonet Receptacles. This was experienced with various types EVA hardware. During the STS-92 (3A) and STS-98 (5A) EVA’s, the Camera Brackets and Socket Caddies (possibly some other hardware as well) became essentially "jammed" in their Bayonet Receptacles. Unacceptable forces were required to remove the hardware from their Swing Arms and in some cases, their T-Bar Assemblies.

A review of design results shows the Vespel Ball Detent provided by the vendor Vlier, is not thermally compatible with our environment. The design allows for dimensional overlap between the ball and housing at ambient conditions, which could result in a press fit at thermal extremes. In addition, the design profile (long thin probe, long tin hole) lends itself to binding when off axis loading is applied to the hardware during removal from the Bayonet Receptacle. Material mismatch (aluminum sockets, stainless steel probes) is causing excessive damage to the Bayonet Receptacles. This could result in unacceptably tight fits at ambient temperatures, which will be exacerbated at thermal extremes.

Characterization test results show Ball Detent force greatly affects the binding characteristics of the design, but even without a Ball Detent, the tool can bind in the Receptacle if the removal force is applied greater than 1.5 inches from the center axis of the Probe. Life cycle tests with Low Force Steel Detent did not pass current requirements (6660 cycles).

Planned testing is to repeat characterization and cycle testing with sockets coated with Tufram and UltraC Diamond. These coatings will increase surface hardness and provide lubrication.

Recommendations include:

Create new Slidelock Receptacle dash number with Low Force Steel Ball Detent and 5-year on-orbit life. Update Slidelock certs to reflect new design.

Upgrade all Slidelock Receptacles on the MWS Gimbal and Swing Arm Assemblies with the new Slidelock dash number and duplicate Gimbal and Swing Arm certs prior to 8A.

Perform maintenance on Gimbal and Swing Arm Slidelocks to either replace the Detent or the entire Slidelock Assy when hardware is returned every 5 years to change Vectran Cords.

Do not incorporate new surface coating design change at this time. It is the opinion of EC5, it is unlikely that the wear to the Slidelock Sockets is contributing significantly to the binding problem. Further, there is no guarantee that existing parts will pass gage after application of surface coating.

Leave on-orbit hardware alone. It is not feasible or cost effective to return all hardware with Slidelocks, nor is it a practical EVA task to remove them. If necessary, detents could be backed out EVA or IVA. It is also possible to "drive out" hardware if a detent becomes frozen.

Decision: Agree with recommendations; EC5 to submit a CR for new dash number in time to support STS-110 (8A).

The oldest FIAR, against the Adaptive Payload Carrier, is 596 days old.

On-Orbit Limited Life Status — NA/Craig Powell

The On-Orbit Limited Life Status was presented. Hardware reported as limited life items were the MUT Tool Carrier, expiring 5/30/01, ORU Transfer Device, expiring 5/01, and Tether Extension Assembly, expiring 9/27/01.

Certification Status — NS22/Greg Wright

There are 16 hardware certification items open for STS-104 (7A). There are 10 open hardware certifications for STS-105 (7A.1). There are no open hardware certifications for STS-108 (UF1).

EMU RDR and Certification Status — NC512/Jose Fuentes

EMU RDR’s open by flight are as follows:

STS-104 (7A) 4

STS-105 (7A.1) 7

STS-108 (UF1) 15

STS-104 (7A) RDR’s were statused as follows:

B-EMU-104-F002, boot fit and H-EMU-490-002, relief valve lock nut adhesive was loose, will be reviewed at the RDR Thursday telecon.

There are 26 open certification items for STS-104 (7A), most require simple paperwork to close out by CoFR2. There are 4 open certification items for STS-105 (7A.1).

Funds Transfer Status — XA/Janice Hall

Funds transferred this reporting period are as follows:

H-0980 — CETA Cart/MT Energy Absorber Coupler – $250K

The Chairman reported that funding for Build Set 1 is in work.

IFA Status — XA/Glenn Lutz

The following IFA’s were statused:

Action STS-92-7: Present action plan and schedule for PGT Chatter FIAR BFCE-029-F105.

USA/Scott Gorrell presented an action status on the PGT Chatter FIAR as follows:

Both flight PGT’s on STS-92 (3A) were flagged for observed oscillation during attempts to loosen bolts and operate a mechanism.

One flight PGT and an engineering unit were sent to Swales for testing. Both units passed all acceptance criteria and the reported condition could not be induced.

Normal post-flight processing was performed at USA on both flight units and they operated nominally.

Two different PGT’s were flown on STS-97 (4A) without incident.

Both PGT’s from STS-92 (3A) have been approved for flight with no subsequent modification or testing. The same PGT’s flew on STS-98 (5A) when the condition was reported on at least one unidentified unit.

Throughout all testing performed at ambient pressure and temperature, the tools operated nominally.

Thermal testing has not been performed. Tools were testing to -50°C to +58°C during PDA. Subsequent use of the tools on EVA make the thermal conditions unlikely to have caused the reported condition. Estimated thermal conditions at time of reported anomaly are under investigation. EMI testing has not been performed; EMI testing was performed as a part of the PDA to 300 Gauss. Subsequent use of the tools on EVA makes damage from excessive EMI unlikely. Estimated EMI conditions at time of reported anomaly are under investigation. Vacuum testing has not been performed. Subsequent use of the tools on EVA make the vacuum conditions unlikely to have caused the reported condition.

Options proposed were to do additional testing to induce the condition, refurbish one or both units, at which time the internal mechanisms can be inspected, or close the FIAR as an "unexplained" with rationale that a workaround is in place if the condition occurs.

Decision: Refurbish the second unit and do additional testing at Swales. The IFA will remain open pending test results.

Action STS-97-7: Investigate low torque light and max torque reading on PGT during EVA1.

USA/Scott Gorrell presented closure rationale for this IFA as follows:

The MOD Anomaly Report describes a low torque error light with a reading of 8.7 ft-lbs. EV1 reported that the torque felt more like 20+ ft-lbs. This anomaly did not occur again, was not reported on the MER Funny List and no FIAR was generated.

A low torque error indicator would result from releasing the trigger prior to applying the programmed torque. If the astronaut thought enough torque had been applied, or the tool twists in their hand allowing the trigger to release, the tool readout will indicate the maximum torque applied. If that torque is less than the programmed settings (minus the tolerance), the low torque indicator will light. Since this anomaly did not occur again and post-flight testing was nominal, this anomaly should be dismissed as operator/reporting error.

DX3/John Haensly may have a video of this anomaly and will be contacted for more information.

Decision: Close unless further information reveals anomaly is more than a one-time event.

Action STS- 98-6 Investigate EVA slidewire anomaly reported by 5A crew and report findings/further action recommendation to EHB.

Decision: Pending coordination with MOD representative.