Minutes of the Tracker Meeting

February 13, 2003


Action Items:

  1. Tom: send the COI coupon drawings to Erik.
  2. Tom: talk to BJ about getting mass estimates updated for CDR.


Action items from last week were reviewed.  All were addressed, except that Tom is still waiting for the composites specification example from Nick.


BJ said that a local Silicon-Valley vendor can make bias circuit with covers, as requested by Sandro.


Thick tungsten order: Althouse signed the purchase requisition.  It is a $100,000 order.  The foils are $10 more than before, because the vendor said they lost money the last time.  There was a bit of an issue with Althouse as to how was this traded with Sandro, as the foils had been an Italian commitment.  Robert asked if we should lower the tolerance further to get the price down.  Gary is rechecking the thickness specification


Luca Latronico said that he will update the web page at Pisa on the MCM testing.  They raised VDD and then the register readout worked on the module that they had problems with last week.  Six MCMs were mounted onto mini-tower trays and retested with no change found.  They are now at G&A for tray assembly. 


G&A has assembled 4 trays with ladders and MCMs.  One will return tomorrow already wire bonded and ready for testing.  Sandro had problem with the pitch adapter on one MCM.  The glue was not holding, so he will try to repair it at Pisa.  Tom apologized that this was a known problem that he forgot to fix before shipping them to Pisa.  Alignment of the ladders in xy is good.  The maximum displacement is 12 microns. 


G&A had problems with the non-conducting Nusil glue for ladder attachment.  Initially they had a 400 micron vertical displacement instead of 150 microns.  The reduced the glue volume and went down to 300 microns.  Then they reduced more and will test again.


Riccardo is in Rome testing the holographic system.  They tested several trays and found the same results as in the shake test.


Erik reported that the modeling is done on the bottom tray.  There are a couple of hot spots still at the sidewall attachment, but he is waiting for new allowables for the sidewall attachments.  The allowables in the model do not reflect the new insert design, so he believes that it will be okay without change. Hytec is testing sidewalls of YS90 to get the needed allowables.


Tom said that he has another set of coupon drawings from COI that he is struggling to open.  He will send the info to Erik.


Erik reported an issue with the corner flexure: in the titanium blade there is a margin of only 10% at 45g random-vibe accelerations, instead of the desired 12%.  On the other hand, new numbers from Martin on the interface loads look good and are no problem.  They are equivalent to only about 22g.  The tower lateral resonance frequency is now up to around 160Hz.


Tom said that he would like BJ to start working on updating the bottom tray drawings.  He needs to get something to COI to start bidding for the closeout material layup.


March 14 is the date to get the reduced model to Martin for coupled loads analysis.  Erik will try to get it there earlier, even.


Erik said to BJ that the core thickness of the bottom tray is unchanged.


Tom will talk to BJ about mass estimates for Martin.


Tom noted that there is a telecon tomorrow on connectors.  The MCM PWB layout update is pending a final choice of the connector. 


Since Sandro was not able to be present, Tom and Robert will call him tomorrow to try to finish the agenda.


Tracker Peer Review Agenda (draft)





Time allocation


Introduction, Overview, & Status

R. Johnson



Schedule Summary & Critical Paths, Risk

T. Borden



Performance predictions vs requirements

W. Atwood



Electronics Design and Status

R. Johnson



Mechanical Design and Status

T. Borden



Engineering Model Tower Status




EM Mini-Tower Status and Results




Safety and Mission Assurance




Parts and materials procurement overview

N. Virmani



Electronics parts and materials

N. Virmani



Mechanical parts and materials




Fabrication Overview




SSD production, receiving, inspection




Ladder fabrication




Tray panel fabrication




MCM fabrication




Tray assembly




Tower module assembly




Product shipping and storage




Test Plan Overview








Electronics Module Testing




Panel and Tray Testing




Tower Testing




I&T Support




On-orbit calibration and test