AMS Tracker Meeting17/10/05 Eric Perrin (GE) Tracker mechanics at Uni -Ge Safety issues Assembly Still to be made

1) Bolt analysis Has been partly done for the 6 structural junctions. - ISAtec extracted the maximum loads on these bolts from the Tracker FEA model. - This for the different load cases, as specified in the structural verification plan. - Antonio Alvino performed the bolt analysis itself - Results showed several negative margins of safety for 5 cases, if improvements were needed, a change for stronger bolts or nuts solves the problem In the case of the Tracker feets to Tracker junction, more investigation of the loads on each bolt was needed and analysis re-made. The « outer bolt » still exhibiting a negative margin of safety on joint separaration Question: Is that acceptable for NASA? (Bruce Sommer investigates) Do we have to increase the size of these bolts and related « IKEA nuts » as proposed by our german colleagues ? Decision on this topic is needed (next TIM). ==> Impact on schedule if conical flanges and shells need re-machining. ==>Fail safe analysis still needed for two junctions Resulting loads will be transmitted to A. Alvino just before next TIM

2) Tracker fastener list and back off prevention method Submitted to Jacobs Update needed for structural fasteners Back-off prevention clear - Two cases: i) Contained small fasteners : Vibratite accepted ii) Other : Vibratite not accepted ==> Mylar patch or self locking insert As this change was announced quite late, several small modifications in existing parts was or is still needed. 3) Fracture of composites Memo submitted to Jacobs. Bala commented that this is sufficient 4) Material list Delivered to Jacobs- Still some issues: - Some al alloy plates to be surface treated in-situ - Proof demanded for a few components prone to stress corrosion

Tracker assembly at Uni-GE The Frankenstein has been moved Into the « Veranda » Modifications can start: - Remove / reposition telescopic supports for inner planes. - Build adapters for conical flanges - Define plane transfer method ==> By hand ? ==> With a lifter ?

Dry assembly has started - Star tracker lower support to upper conical flange. - P1 to top conical flange - P5 to bottom conical flange. - Spl brackets for evaporators

Assembly schedule Inner Tracker assembly can start as soon as : - The three inner planes are ready for assembly  ~End of November Delayed because of a missing ladder - The modifications to Conical flanges / Shell are made (if needed) - The Star Tracker lower supports are bonded to the top conical flange - The fasteners are available Assembly sequence - Transfer the 3 inner planes into the « Frankenstein » in order P2, P3 and P4 - Transfer the conical flanges into the « Frankenstein » - Position planes and connect thermal connectors - Mount cable support structure - Mount and connect cables on ladders of three external rows +Y and -Y - Mount the two 100° shell sectors - Mount and connect all other cables - Mount the two 80° shell sectors Inner Tracker assembly ==> Duration ~2.5 months ~End February2006 if assy starts early December

P5 completed with ladders  ~Mid February 2006 P1 completed with ladders  ~End of March 2006 (Test are not accounted for ) Still a lot of things to finalize / to do for the assembly of the Inner Tracker: - Procure fasteners which need to be replaced - Shopping list for next TIM - Light tightness at exit of conical flange / around the feets - Mesh on light traps - Bond Star tracker lower support - Cable clamps - Structure to support cables - Container for Inner Tracker. - Etc...

Further assembly steps / parts needed - Re-do some bracketry for evaporators in two parts - Mount outer evaporator rings to P1 and P5 - Modify outer plane containers to be compatible with evaporators For integration - Inner Tracker handling gear - Installation jig for Inner evaporator (design A. Alvino) - Cable « paddle » and clamps on Vacuum case (design A. Alvino) - Cable balcony for Tracker crates. Miscellaneous - Prototype condenser - Parts for heat exchanger