EVA AIT Minutes 8 August 2000

To: Distribution

From: XA/Nancy J. Patrick

Subject: Minutes for August 8, 2000 EVA AIT

The EVA AIT met at the Johnson Space Center on August 8, 2000. The scheduled Crew Consensus Issue review was preceded by a special topic discussion noted below. (Minutes for the Crew Consensus Issue Review are contained in the CCR Issue database and are not included in this discussion. Boeing/Lou Ramon and XA/Nancy Patrick co-chaired the meeting. Representatives from CB/Flight Crew Operations, XA/EVA Project Office, DX32/EVA Systems/Mission Operations, and OC/ISS Operations/Launch Package Team were present. Copies of presentations can be obtained from XA/Charlotte Shannon, Building 1, room 661, (281) 483-5259.

1. VSIP Follow-up SSCN 3730 Assessment DX32/Chris Looper

Mr. Looper presented the timelines developed to address the requirement to maintain P6 prior to MT/CETA rail delivery. Mr. Looper’s assessment included a detailed timeline for a battery or BCDU changeout, including the EVA overhead to get the ORU to the worksite and to return to the baseline configuration after the changeout is complete. Mr. Looper made the following assumptions

• ESP 2 is not re-locatable (baseline)
  
• SSRMS is available but not SPDM (baseline for part of the time period in question)
  
• SSRMS can reach far enough out on P5 to hand-off the ORU to the Crane at a WIF which allows the Crane to which the ORU worksite (needs confirmation)
  
• ORU change-out does not require any thermal or other stabilization period – the only timeline drivers are the time required to drive the bolts and EVA actuated interfaces
  
• An interface plate is provided which allows temporary stowage of an ORU on the MBS with power provided (not the baseline but an informally recognized requirement)
  
• No CETA cart relocation is required for the MT to reach the outboard utility port on P3 (not the baseline)
  

• EVA 1 (Day 1) Install ORU on MBS, locate Crane and APFR on P6
  
• Day 2 – off
  
• EVA 2 (Day 3) Relocate port CETA cart to starboard
  
• Day 3/Day 4 – Translate MT/MBS to P3
  
• EVA 3 (Day 5) – Transfer new ORU to worksite, R&R ORU, Transfer old ORU to MBS
  
• Day 6 – Translate MT/MBS to S0
  
• EVA 4 (Day 7) – Relocate old ORU to ESP, Relocate 1 CETA cart back to port
  
• Day 8 – off
  
• EVA 5 (Day 9) – Transfer Crane, APFR back to CETA cart
  

The time that the ORU is unpowered during the change-out scenario, (assuming power is provided on the MBS through the interface plate) is reduced to 2:35 minutes. OC/Ron Torcivia noted that the SSU can only survive 2 hours without power. The EVA AIT noted that this would be an unacceptable limit regardless of the rail/no rail question, since you can’t guarantee any ORU changeout can be accomplished in that time, and that all ORUs should remain viable for the duration of an EVA. CB/Fernando Ramos indicated that there may be ways to streamline the EVA time by changing when the CETA cart relocation is performed, however they may result in longer times without power for the ORU, so the EVA AIT concluded this is the only safe scenario given the current level of knowledge.

The EVA AIT then compared this scenario to the scenario with the rails present and concluded that having the rails saves 2 EVA sorties, because you can avoid the Crane, APFR and CETA cart relocations. Should the program provide a re-locatable pallet, you can save another 1-2 EVAs (for a total of 1-2 EVAs). The re-locatable pallet also provides the ability to change out multiple ORUs since they can all be transported to the worksite at the same time. (This may be feasible during this timeframe without changes to the baseline, because the P3 pallet locations are available if the pallets are manifested, and the P3 attachment is the same mechanism as the MBS/UMA. The ESP2 is not currently re-locatable, however it was added to the program to provide an unpressurized stowage capability prior to P3’s arrival).

The EVA AIT then addressed the P6 ORUs that cannot be handled without the robotic support provided by the rails. These ORUs are:

• Blanket boxes
  
• Cable boxes
  
• Mast Canister Assembly
  
• PV Radiators
  

OC/Ron Torcivia agreed to discuss the data provided with the OC/Bill Robbins, the L&M lead, to determine if the program can handle the additional EVA overhead associated with maintaining P6 prior to rail delivery, and criticality of the ORUs that cannot be installed. Mr. Torcivia will present to the VSIP in the next couple of weeks.

Action Item Closure: AI-526 was closed