1 FGS Guider CDR – April 19, 2007 © Copyright 2007 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS Guider Critical Design Review March 14 th & 15 th 2007 COM DEV Ottawa 303 Terry Fox Drive Kanata, ON, K2K 3J1 Pierre Chayer (HIA/STScI)

2 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS-Guider CDR The Critical Design Review (CDR) is a presentation of the detailed instrument system design. CDR allows for the final FGS requirements, resource allocations, verification plans, and detailed designs to be presented, discussed, modified (if necessary) and approved. CDR discloses the complete system design in full detail. CDR ascertains that technical problems and design anomalies have been resolved. CDR ensures that the design maturity justifies the decision to initiate Flight Unit fabrication, integration and verification of mission hardware and software.

3 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS-Guider CDR Agenda (Day 1)

4 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS-Guider CDR Agenda (Day 2)

5 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS-Guider Operations

6 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada Identification: Guide Star Recognition guide star full frame readout, pattern match of observed stars to uplinked reference stars to identify guide star pixels (2.3 ') 2048 pixels (2.3 ') FGS FOV

7 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS-Guider Optical Layout Pick-off mirror TMA Focus mirror Detector

8 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS Optical Assembly - Guider Side

9 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS Optical Assembly - With Baffles Guider Plan View

10 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS in the ISIM Structural Context MIRI NIRCam NIRSpec FGS-TFI FGS-Guider

11 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada Main Bench Design Features 2 mm thick ribs, 90mm deep Higher density rib pattern Structure added to bolster KM2 – KM3 span 4 mm thick sidewalls, 110mm deep Thermal strap wall 6mm thick Hardpoints added for MGSE Guider POM deck raised KM mounting pad thickness increased to 21mm

12 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada Thermal Analysis: Cold Steady State Cold Case: Requirement Tested: Detector absolute temperature below 41 K Boundary Conditions: ISIM Conductive temperature = 30.0 K Radiative Environment = 32K, ε =0.01 Heat strap interface temperature = 30.0 K Steady State Heat Loads Results Maximum detector temperatures ( K) are well below the requirement. Gradient in the optical bench is K

13 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada FGS Identification Timing Budget Identification duration is dominated by the readout time for the double read Double read = reset-read-reset-read, allows Cosmic Ray hits to be filtered out. As per agreement post-ISIM PDR, FGS allocation of 45 sec applies to readout time only FGS & ISIM collaborate on overall timing estimate for ISIM allocation of 60 seconds ID duration estimate is compliant at the ISIM level (< 60 secs per ID attempt, ISIM-266) ContributorFGS FSW CommandItem Duration (seconds) Total Duration (seconds) Note SP / ICDHID & SCE Setup Commands Includes first start exposure command FGSStrip Readout Duration Double Read: 34 strips (4 pixel overlap assumed) FGS Requirement (SRD154) FGS/ ICDHStrip Data Transfer Time0.95Does not contribute – shorter than readout FGS FSWLast Strip Image Processing Only the last strip image processing time adds to the total FGS FSWIdentification Algorithm7.198 Algorithm assumes 50 bright objects & 30 triads SP / ICDHFGS & ICDH Clean up commands Total58.46 Requirement at ISIM level is < 60 seconds

14 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada Non-Compliance Statement SRD154 Requirement text - The total time for an identification image to be collected, plus execution of the identification algorithm shall be 45 seconds or less (per attempt) Traced from – IPFR requirement FGS237 Status – The estimated duration is s Discussion – Excess duration is due to need for double detector read to mitigate SEU. See Section 09B of this package for further details. It has been agreed that the requirement should be against the readout time only Proposed resolution – Raise Class 1 ECN to remove algorithm execution time from requirement. Discuss with CSA and NASA and come to a consensus on path forward on residual non-compliance. Likely acceptable as is

15 FGS Guider CDR – April 19 th, 2007 © Copyright 2006 Her Majesty the Queen in Right of Canada Subject to Controlled Goods Regulations of Canada Pack and Ship June 2009