Minutes of the April 8, 2004 Tracker Meeting




D. Rich

B. Rodini (Swales)

M. Menning

A. Scholz

A. Nguyen

J. Tice

D. Marsh

L. Klaisner









Tom V.



Action Item Summary:

  1. Nanda: get clarification from Plyform/COI on meaning of “previous order” for prepreg material.
  2. Jeff Tice/Dave Rich: Titanium washer issue---do new ones need to be made?
  3. All: resolution of PRR dates and travel plans
  4. M. Nordby/D. Rich: list of top-tray changes
  5. Riccardo: identify key dimension inspections needed for Ti parts
  6. Riccardo: send redlines for mid-tray drawings (as-built vs as-drawn) to SLAC
  7. Jeff Tice: provide INFN ship dates for bottom tray closeouts
  8. M Menning: distribute information of proposed Grid-side I/F changes (done)
  9. M. Nordby: distribute draft alignment plan for review (done).  Schedule date for follow-up presentation meeting.


Agenda, with notes added by David Rich:

1.    Sidewall prepreg procurement status

Plyform is preparing the PO to COI and will send it out today or tomorrow.  A question was asked by COI whether materials from the previous order would be acceptable for this buy.  Ben Rodini said that it would be good to use the previous lot if this meant “fabric” as opposed to finished prepreg.  Ben requested clarification what “previous order” applied to.


ACTION-  Plyform to clarify what “previous order” meant.  Fiber has no shelf life issue.  Or is this mix prepreg which would have a shelf life constraint.  Nanda to forward response once received.  Sandro stated that just-in-time need delivery date would be second week of June.


Sandro asked whether SLAC was going to furnish the Ti inserts (washers).  Jeff T. explained that the Ti Inserts (existing design) are in flight stores at SLAC but Martin Nordby is redesigning them to increase clearance between towers.  Some discussion developed as to “why are we changing these inserts”.  The team agreed that only “MANDATORY” not “nice to have” changes would be acceptable.


ACTION- J. Tice to ask M. Nordby to provide justification for design change of Ti inserts.  Sandro stated that the need date for these Ti inserts in Italy is end-of-May.  If a new Ti insert design is required, then an NCR must be generated to “scrap” the current stock on-hand.  (If the current insert design is deemed acceptable, J. Tice is to ship the existing Ti insert inventory to Italy ASAP.)



      2. Proposed visit to Italy 1st week of May (3-7):


ACTION-  Resolve PRR dates and establish travel plans.

Nanda explained that although he agreed that these are important items, due to other obligations he did not feel that INFN could meet with us as outlined below.  INFN would prefer to hold the PRRs in Pisa a week earlier.  Dave said we would take this discussion off-line with R. Johnson, D. Marsh, M. Nordby and himself.  We must get this resolved so R. Ruland (and others) can make travel plans accordingly.  Ruland is on travel next two weeks.


            - From U.S.: Rich, Nordby, Marsh, Johnson, Ruland, maybe more

- Bottom/top tray drawing review with Plyform and PRR for bottom/top tray fabrication.  Nanda indicted that Bottom Tray PRR should be pulled in to end of April to not impact build schedule.


ACTION-  Martin Nordby to provide “punch list” of proposed changes to top tray.  Only MANDITORY CHANGES should be considered.  INFN needs to know prospective changes and any impact to tooling.  Improve communication of proposed changes to enable assessment of impact to tooling or assembly process by INFN.


            - Review of mid tray fabrication progress at Plyform (need assembly drawings updated in preparation)

            - Discussion at INFN Pisa of alignment (with R. Ruland)

            - Review of flight MCM incoming procedures

            - Planning for G&A tray assembly PRR (needs to be quite soon after this---like the following week!)


3. PRRs: need to start preparing action item lists for documentation, drawings, etc that need to be in place for a successful PRR  Deferred discussion pending resolution of Item #2 above.

      4. Bottom tray assembly fixture drawings

      5. Top tray drawing status (see above: action for top tray punch list

      6. Static test preparations for April 19-23 visit:

            - Ku, Molini, Swensen

            - Static test planning

            - Preliminary static test

Meeting date in Pisa confirmed.  Hotel arrangements made by INFN at Hotel Leonardo for SLAC travelers.  Nanda- Thanks!  Marble table delivery is scheduled for 4/19 (just-in-time?).  Andrea sent e-mail (4/8/04) indicating that Adapter Plate between Static Test Fixture and Marble is made of aluminum not steel. 

      7. Alignment plan: Martin to present the plan at the 4/20 engineering meeting (TBR)

ACTION (DONE)-  Martin N. to distribute draft alignment plan for review.  Schedule follow-up presentation meeting to review, incorporate changes and release.  4/20/04 was tentative date, but team would prefer to pull this date in approximately 1 week.  Meeting date to be established and distributed.


      8. Status of bottom-tray and interface parts (titanium, core, closeouts, cones & studs. . .)

Flexures- First bottom tray set (plus some extras TBD) of Flexures slipped to 4/19.  100% inspection to be performed on first two ship sets (two bottom trays worth).  Complete production is now targeted for end of April.  J. Cullinan (SLAC QE) is visiting Advanced Machine today.  There was some discussion on what are the inspection requirements for the remaining items.

ACTION-  Ricardo to identify key critical dimensions from existing design drawings which INFN recommends be inspected for each part.  Main area of concern is corner brackets and flexure orthogonality and cone axis.

Cones-  Mike M. reported that (Qty 36) three tower sets of non-flight cones have been purchased.  The first purchase was made (on credit card eliminating PO lead-time) for Qty 2 non-flight joint sets delivery due 4/22. Delivery date of remaining 34 pieces is TBD.  Jeff T. will get delivery date early next week.  Final flight drawings are in check.  Flight drawings must be released and PO issued (DATE TBD).

STUDS-  SLAC ordered qty 36 non-flight studs.  The coating and locking feature were eliminated to expedite procurement.  Coating may not be required pending resolution of whether a steel bushing is required in the grid.  The locking patch is not required for static testing but must be applied for vibration testing. 


Mike M. explained that the Grid interface design is being evaluated for change by Rob Black because the Grid machine-shop cannot hold the concentricity tolerance of Keensert with respect to the press-fit bushing.  Sandro expressed concern that steel bushing in Grid should be provided due to bearing stress damage exhibited in EM Vibe failure.  Mike explained that the bushing in the design was actually used as “filler material” due to the OD bore of Keensert and was not considered to be needed for bearing strenth.

ACTION-  Mike Menning is to distribute Rob Black’s sketch of proposed changes to Grid interface and John Ku’s stress analysis.

BOTTOM CORE- Bottom tray core design is in the release cycle.  The PO is in process per J. Tice.  The plan is to purchase replacement cores with correct dimensions and ship to Italy.  The contingency plan, if procurement looks like it will not meet the need date, is to rework to print and trim some existing cores (which are currently at Plyform).  Sandro indicated that for political reasons with Plyform, he would prefer replacement cores.  Estimated need date is 3 days before flexures arrive in Italy (approx. 3 weeks from now).  D. Marsh said that a SLAC NCR has been created.  The discrepant materials must be segregated from replacement cores so mix-up of different sizes is avoided.

BOTTOM TRAY CLOSEOUTS-  Joe Cullinan is at COI today for 1st article inspection.

ACTION-  Provide INFN ship date for Bottom Closeouts.



      9. Material procurement for bottom/top tray inserts; plans for machining the inserts. 

J. Tice has procured 50 meters of T76 Aluminum, which will be drop shipped to Pisa.  Pisa should receive this material next week.  INFN indicated they are ready to fab inserts pending arrival of material.  MRB disposition was to scrap top and bottom tray (T6) inserts and replace with T76 Alum.  Note: Tom V. said he would like to revisit requirements with GSFC regarding scrapping top and bottom tray inserts (T6). 

      10. MCM flight production status 

Albert Nguyen gave MCM status.  The first five units are expected to be delivered 4/23 from Teledyne, with the 25th MCM due 4/30.  SLAC then must perform T/C, burn-in, and final test.  This is anticipated to take approx. 8-9 days.  (Note added by Robert: Teledyne is presently ahead of this schedule and will continue to try to compress it.  SLAC will start burn-in of the first 5 as soon as they are received, to get MCMs flowing to Italy asap.)

      11. Review old action items

      12. A.O.B.



Nanda Menon’s notes:

1. The Ti inserts for the side walls are in SLAC flight stores and will be sent to INFN

2. The Alignment plan is to be sent to INFN - done. INFN requests that the PRR/TRR be conducted this month (April) with closure on or before 7th April and not be held that week. Offline discussion with DR/AB/NM

3. Same as #2.

4. The BT tooling work has started in G&A.

5. We need the TT drawings ASAP with only "cannot live without" changes

6. Static Test team from SLAC visit week 19 April proceeding well. Hotel reservations OK. Andrea to send detailed list of items received to John/Mark this week. John will have the load vales that are to be used for the BT static tests for the Tower A and subsequent.

7. Alignment plan to be sent - received and in review. Looks quite involved.

8. Flexure - first SS 19 April @SLAC with full measurement. The remainder of the flexures at the end of April at SLAC. INFN requires

that all the flexures be subjected to 100% measurements prior to shipment to them. They are looking for a certificate of conformance

with measured data. They further noted that the closeouts and trays and towers all go through 100% measurements and expressed perplexity at the lack of measurement of the flexures as they are fundamental in the alignment process. Riccardo to supply a list of measurements that he deems necessary to be performed on all the Flexures.  2 sets of cones purchased and will be delivered on 22 April. The other 34 sets have been PO'd and a delivery date will be available fro JT on 14 April. The 2 initial sets are to be used for the static test of the EM and Tower A BTs.  There was a short presentation by MM of the current Grid design and it showed us reverting back to the previously failed metal combination of Steel bolt in an Al threaded hole.  (Nanda: this is not correct, the threads will not be aluminum in any case---R.J.) INFN expressed strong views against it. MM to forward the new Grid sketch to Sandro.

The Cores for the BT will be available ~3 weeks from now. SLAC to send the NCR they have generated for the substitution of the cores so that INFN can generate a NCR and coordinate this effort with PF.  COI closeout ship date to be indicated in the MOM from DR.

9. T76/T6 discussion was short where TV indicated that there does not seems to be any distinction from NASA point of view between the mid, top and bottom tray inserts contrary to the SLAC MRB. He will investigate further. T76 tubes are to ship next week per JT.

10. The first 5 MCMs will ship to SLAC 23 April and the rest 20 on 30 April. The need date in-order to maintain current schedule is 7 May in INFN for the incoming inspection process and in G&A 15 May.

11. INFN had decided, for programatic reasons, to leave the BT cores in PF till the new set arrives. The Clamp drawing or ideas to be sent to Pisa. Nanda was under the impression from the discussion at prior telecons that the clamp was an existing design. Sandro has put the environmental data on the GLAST web site. The epoxy issue has been closed with the drawing updated. The TV cable length was defined as 10 meters minimum. The schedule for this to be included in the telecon MOM.

12. JK is the point of contact for Nicola for the EM vibration test activity coordination.



Last Week's Action Items

Sandro & Nanda: take some bottom-tray cores back to Pisa to be trimmed.

Status- On hold pending delivery of replacement cores.

Mike: send Pisa a drawing of the clamp fixture

Status-  Concept drawing to be sent 4/9/04.

Sandro: put the environmental recorder data from transportation in Italy onto the web

Status-  DONE 4/8/04.


Old action items:

1. Robert: give Jeff Tice information to procure cables for T/V testing (need length info)

Status-  DONE

2. Mike: correct the epoxy called out in the BOM for closeout assembly (and other tray drawings)

Status-  Update required for mid-tray drawings.  Complete for Top Tray and Bottom Tray.

3. John Ku and Mike Opie: draft or redlined static and vibe test plans

Status-  Static and Vibe test plans being revised.  J. Ku will hand-carry to INFN on 4/19.