Backplane test article is subset of PMBSS

 Need to understand performance at level we can allocate wavefront error budget at nm levels

- goes to image stability and image quality
      - what happens when we go from ambient to cryo
      - stability during norrmal JWST operations

 Oversight of test definition: emphasize oversight of PIT
 

 Firewall between modeling and actual tests

 takeaway we understand the backplane and how it will perform on orbit and during I&T