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Updates on ACS-R

Updates on ACS-R. Marco Sirianni October 18, 2007. Agenda. ACS Status ACS-R Concept Schedule EVA activities Role of STScI. Status of ACS. ACS Side 1 Failed on June 19, 2006

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Updates on ACS-R

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  1. Updates on ACS-R Marco Sirianni October 18, 2007 TIPS - October 18 2007

  2. Agenda • ACS Status • ACS-R • Concept • Schedule • EVA activities • Role of STScI TIPS - October 18 2007

  3. Status of ACS • ACS Side 1 Failed on June 19, 2006 • The ARB identified a most probable candidate for the failure, an Interpoint DC-DC Converter on LVPS 3 board in MEB1 • Precluded all WFC and HRC CCD imaging. • Operations started on side-2 electronics on Jul 4 2006. • ACS Side 2 failed on January 27, 2007 • Short likely in the Hold Bus • Side-2 is completely inoperable • Side-2 is inaccessible to astronauts for repair • Side 2 is not part of repair mission • ACS was configured for Side-1 SBC operations only on February 15, 2007 TIPS - October 18 2007

  4. ACS-R • Immediately after the failure of Jan 2007 the HST project assembled a team for the repair of ACS. • At the end of February a specific option was select for further study. • On October 3 & 4 the ACS-R project passed the critical design review. TIPS - October 18 2007

  5. ACS-R CDR TIPS - October 18 2007

  6. ACS-R Team TIPS - October 18 2007

  7. ACS Current state simplified Electrical Block Diagram WFC CEB HRC CEB WFC CCD HRC CCD PDU 20 Amp Fuse PDU 20 Amp Fuse Side 1 Side 2 HOLD Bus HOLD Bus APB APB +15, -15, +35 +15, -15, +35 LVPS H LVPS H +5 +5 LVPS O LVPS O OPERATE Bus OPERATE Bus Failed Element Suspect Element MEB MEB Side 1 is fully operational except for the LVPS power to the CEBs. Currently running on Side 1. Side 2 is inoperable. TIPS - October 18 2007

  8. ACS-R concept Restore WFC functionality under side-1 (LVPS failed on 6/2006) by replacing the WFC CEB cards with a new module (CEB-R) powered by a new LVPS (LVPS-R) Restore HRC functionality by backpowering the existing HRC CEB (the success depends on the status of the existing wire harness within ACS) Requirement: do not harm SBC TIPS - October 18 2007

  9. ACS-R simplified Electrical Block Diagram HRC CEB HRC CCD New Power Supply PDU 20 Amp Fuse PDU 20 Amp Fuse New CEB Side 1 Side 2 WFC CCD HOLD Bus HOLD Bus APB APB +15, -15, +35 +15, -15, +35 LVPS H LVPS H +5 +5 LVPS O LVPS O OPERATE Bus OPERATE Bus Failed Element Suspect Element MEB MEB New Element Side 1 used to operate the entire instrument except for the CEBs which are replaced/powered by a new box. Side 2 is inoperable. TIPS - October 18 2007

  10. ACS-R Design Concept PIE = Power Intercept Element CEB-R = CCD Electronic Box - Repair LVPS-R= Low Voltage Power Supply - Repair POE = Power Output Element LVPS-R POE CEB-R PIE TIPS - October 18 2007

  11. Astronaut Handrail CEB Electrical Interface Conector TIPS - October 18 2007

  12. CEB-R Replace the original 4 boards with a new element which contains 4 replacement boards Backplane Timing Board Clock A/X Board Clock B/Y Board Motherboard Mating Connectors ASPC/Bias Board TIPS - October 18 2007

  13. LVPS-R PIE Connector Cover with Tether Ring POE Tether Ring LVPS-R Grounding Plug Cable Stowing Post Attachment Clamp Handrail Post ACS Handrail TIPS - October 18 2007

  14. HRC Backpowering • The ACS-R design provides the option of backpowering the existing HRC CEB through the existing harness within the instrument. • One of the main issue is the supply of the +35V. If it can be provided by the original LVPS than it will be sincronized (-> lower noise), but it must be provided by the LVPS-R HRC could be noisier. • Preliminary tests with flight spare HRC CEB and CCD show no difference TIPS - October 18 2007

  15. ACS-R Testing Besides the single component testing the full ACS-R system will be tested with: • Flight spare HRC CEB (backpowering testing) • Flight spare build for HRC and WFC • Cannot be cooled as on-orbit • Used for testing with hi-I preamp and detector • Functional testing when lowest noise is not needed • WFC SITE spare CCDs (+custom cryostat) • Can be cooled to -80 C, crosstalk testing • CCD emulator • allows readout of a complete 4Kx4K image • adjustable noise level: • Match on-orbit detector level to determine expected performance • Set noise level very low to verify noise contribution of CEB-R • Set noise level high to optimize timing pattern and CDS for best results. TIPS - October 18 2007

  16. Schedule Highlights • Testing with the first engineering module of CEB-R and ACS flight spare CCDs will start on Oct 25th. • Flight LVPS ready Mid Jan • Flight CEB-R ready early March • Servicing Mission Ground Testing (SMGT) End of February (possibly a second campaign with complete flight-hardware) • TV testing - April • Shipment to KSC - Jun 9 • Launch - August 8 TIPS - October 18 2007

  17. Current Timeline TIPS - October 18 2007

  18. EVA Tasks • All ACS Repair EVA tasks have been evaluated by suited SM4 crew • ACS Prep 00:05 • Install Guide Studs 00:20 • Remove the EMI Grid 00:10 • Install grid cutter, actuate, remove grid cutter w/grid • Remove WFC Access Cover Plate and CEB Top Plate 00:45 • Install FCP, release fasteners, remove FCP • Remove 4 WFC CEB electronic boards 01:00 • Install WFC CEB Replacement Module 00:10 • Install Power Supply Module to ACS handrail, mate PIE connector to LVPS-R and POE connector to CEB-R 00:10 • ACS worksite clean-up 00:20 • Total (w/o door operations) 03:00 • The EVA timeline will continue to be refined through upcoming scheduled NBL • crew training and test runs as well as 1-G activities to address open issues on • tool stowage, tool design, fastener access, etc. TIPS - October 18 2007

  19. EVA Tools Screen Grid Cutter Card Extraction Tool Fastener Capture Plate TIPS - October 18 2007

  20. The role of STScI • Support ground calibration to identify areas where science operations may need modification (commanding, proposal preparation, data processing) • Support IPT in the definition of the ACS-R AT/FT • Support the scientific evaluation of the FT • SMOV planning and on-orbit re-commissioning TIPS - October 18 2007

  21. ACS-R in SMOV • ACS-06 CCD Functional Test\ • ACS-08 WFC CCD Cross Talk • SMOV WFC and HRC observations will be kept in separate proposals/visits to facilitate operations in case of unforeseen problems with the HRC backpowering. • Cycle 17 calibration programs will overlap with SMOV and will provide further characterization of the instrument. • We will include, as part of cycle 17 calibration plan, a “CCD optimization” program to investigate the benefits of operating the CCDs with a reduced clocking rate and clamp and sample scheme. The full impact on science operation (read noise, CTE, dynamic range, readout time) will be evaluated before making new options available for GO science. • This program will be executed promptly if the noise characteristics of the default configuration are not satisfactory. TIPS - October 18 2007

  22. Conclusion • ACS-R successfully passed CDR • More integrated testing will start soon • STScI will be more involved in the future starting with the ground testing -----Original Message----- From: Weiss, Mike Sent: Thursday, October 04, 2007 10:33 PM To: Smith, Hsiao Subject: Way to Go! The ACS Repair just pulled off a miracle! You should all feel extremely proud of what you just accomplished, and I'm sure that you do. Please pass on to Ed, Pete and the entire team gratitude from not only the HST Program Office but from anyone in our Agency who may feel that NASA no longer has the "Right Stuff." ACS Repair has just proved them wrong. Superb effort on the part of all! Mike TIPS - October 18 2007

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