1. Venus Observations Flight Readiness Review (HST Program 12433) 22 December 2010

2. 2010/2011 Venus Observation P. 2 22 Dec 2010 1.0 Venus ObservationTony Roman 2.0 FSW, S/C H/W Changes and Implementation Brian Vreeland 2.1FSW and/or S/C H/W Functional Changes 2.2FSW Software Structure/Resource Changes 2.3Supporting Ground System Changes 2.4Supporting Documentation Changes 2.5Release Messages 2.6Unit and Build Level Testing/Results 2.7System Level Testing/Results 3.0Engineering Test / Installation 3.1Overview and Initial ConditionsBen Teasdal 3.2Script ReviewBen Teasdal 3.3Standalone Testing Mike Wenz / Steve Arslanlian 3.4Timeline ReviewBen Teasdal 3.5MEGGBen Teasdal Agenda

3. 2010/2011 Venus Observation P. 3 22 Dec 2010 Agenda 4.0 Monitoring and System Impacts Wayne Burdick 4.1On-orbit Validation / Monitoring 4.2System Impacts 4.3Supporting Operations Changes 4.4Supporting PRD Changes 4.5Training Module Changes 5.0 Constraints and Restrictions Review Wayne Burdick 5.1CARD 5.2OLD 6.0 Contingency Planning Wayne Burdick 6.1 Vehicle Contingencies 6.2Other Contingencies 7.0 Engineering Support RequirementsWayne Burdick 7.1Personnel 7.2Communications / Data 7.3CCS 8.0 Liens / IssuesWayne Burdick 9.0 Forward PlanWayne Burdick 10.0 ActionsWayne Burdick

4. 2010/2011 Venus Observation P. 4 22 Dec 2010 Engineering Team STScI - Tony Roman, Merle Reinhart, Alan Welty, Charles Proffitt OTA - Mike Wenz, Dennis Crain, Art Bradley DMS / I&C– Ben Teasdel and Jessica Regalado FSW – Brian Vreeland, Norm Roy, Shirley Duhaney, Suzanne Benedict, Susan Lien, Vicki van Duyl, Anthony Wells, Clive Caldwell, Linda Mitchell Payload FSW - Dennis Garland PCS – Dave Murphy EPS – Stan Krol SI – Scott Swain Thermal – Josh Abel Safing – Ed Moy Operations – Lynn Bassford, Joe Cooper Systems Management – Wayne Burdick

5. 2010/2011 Venus Observation P. 5 22 Dec 2010 Objectives & Overview Explain Venus observing strategy. Review areas of special concern with Venus observations and explain how these concerns are being addressed. Determine if the implementation is correct and complete. Why is Venus Special ? At its farthest, Venus gets to be about 47 degrees from the Sun. HST is normally not permitted to point within 50 degrees of the Sun.

6. 2010/2011 Venus Observation P. 6 22 Dec 2010 Venus Observing Program History In 1995, HST observed Venus with GHRS and WFPC2 (GO 4518 and GO 5783). In 1996, two GO Venus proposals (6607 and 6771) were approved by the TAC; and there was one GTO/WF2 program (6851) to observe Venus. All of these were cancelled by the STScI Director shortly after phase 2 submission. In 1997, there was a GTO/STIS program (7581) to observe Venus. Much implementation work was done, but the program was then withdrawn by the PI. In 2003, HST observed Venus with STIS (GO 8659). NASA program 12433 is now planned for: December 27-28, 2010 (2010.361-362) January 22, 2011 January 27, 2011

7. 2010/2011 Venus Observation P. 7 22 Dec 2010 Goals & Strategies Scientific Goals Coordinated observing with ESA’s Venus Express mission. Map variations in SO 2, SO, S 2, and other UV absorbers. Constrain models of Venus atmosphere and climate evolution Observing Strategy Observe while Venus is near maximum elongation Observe while HST is in Earth’s shadow A window of 9-14 minutes per orbit Three visits of 2 orbits each. Originally to have also been coordinated with Atkatsuki mission, but that spacecraft failed to achieve Venus orbit

8. 2010/2011 Venus Observation P. 8 22 Dec 2010 Target Visibility GS Pair Acq at Venus+5D Slew to Venus Target Visibility Shadow GS Pair Acq at Venus+5D Observing Strategy Details Initial GS Acq at Venus+5D A pointing 5.5 degrees from Venus and 51.6 degrees from the Sun. Minimizes slew distance to Venus Precautionary measure to protect against large pointing error after slew Observe Venus Slew to Venus +5D Single GS Acq at Venus OBAD Target Visibility Slew to Venus Shadow GS Pair Acq at Venus+5D Observe Venus Slew to Venus +5D Single GS Acq at Venus OBAD

9. 2010/2011 Venus Observation P. 9 22 Dec 2010 Target Visibility GS Pair Acq at Venus+5D Slew to Venus Target Visibility Shadow GS Pair Acq at Venus+5D Observing Strategy Details Single GS Acq at Venus Saves about a minute versus pair acquisition Venus science observation 153s exposure STIS auto wave cal disabled Observe Venus Slew to Venus +5D Single GS Acq at Venus OBAD Target Visibility Slew to Venus Shadow GS Pair Acq at Venus+5D Observe Venus Slew to Venus +5D Single GS Acq at Venus OBAD

10. 2010/2011 Venus Observation P. 10 22 Dec 2010 Venus Appearance at Observation Apparent magnitude: -4.1 +/- 0.2 Surface brightness: +1.5 (average for 1 square arcsecond of illuminated portion of disk) Apparent diameter: 28.5 arcseconds Phase angle: 97.3 degrees

11. 2010/2011 Venus Observation P. 11 22 Dec 2010 Vital Statistics Observation Science Exposure Time Angle to Sun Limb (degrees) Sunlit Time inside SAZ While Slewing Away from Venus Guide Star January 199522-109s per orbit 46.32m 20s January 2003255s46.02m 30s Dec 28, 2010 orbit 1153s46.22m 14s (after GS time adjust) S924000129 in FGS1 on centerline Dec 28, 2010 orbit 2153s46.23m 2s (after GS time adjust) S924000129 in FGS1 ~50” from centerline Jan 22, 2011 orbit 180s (153s requested) 46.12m 38sS8OF000650 in FGS1 Jan 22, 2011 orbit 280s (153s requested) 46.12m 36sS8OF000650 in FGS1 Jan 27, 2011 orbit 1314s45.72m 56sS8LA045471 in FGS2 Jan 27, 2011 orbit 220s45.70m 0sS8L2047229 in FGS1

12. 2010/2011 Venus Observation P. 12 22 Dec 2010 Areas of Concern Guide star acquisition failure Spacecraft or instrument problem shortly before scheduled observing time FGS exposure to Venus HST being exposed to sunlight while pointed within the Solar Avoidance Zone (SAZ) HST safing while pointed within the SAZ

13. 2010/2011 Venus Observation P. 13 22 Dec 2010 Guide Star Acquisition Failure Concern If attitude error is greater than the search radius, the guide star acquisition could fail resulting in the loss of the science. Precautions The chances are minimized by the short 5 degree slew to Venus. Too late to perform guide star acquisition test. Stars are in solar avoidance zone. Science exposures will proceed even if GS acquisition fails. Special commanding specified to ignore “take data” flag. AQEXPIRE timer adjusted via SMS edit. Detector is protected because HST is in shadow CCD is utilized for observation

14. 2010/2011 Venus Observation P. 14 22 Dec 2010 Problem Shortly Before Observation Concern An unrelated problem may threaten the Venus observing window. In 1995, the Venus observation was originally lost due to an unrelated safing; but it was quickly replanned and executed successfully. The 2003 Venus observations were delayed from 2001 due to the failure of the STIS side 1 electronics. Remedy Second choice coordination opportunity with Venus Express on January 23, 2011

15. 2010/2011 Venus Observation P. 15 22 Dec 2010 FGS Exposure To Venus Concern If the attitude error is large enough (> 300 arcseconds), an FGS could possibly see Venus and cause potential bright light exposure to the FGS photo-multiplier tubes. Precautions Choose a guide star that is as far as possible from Venus. The chosen guide star is magnitude 12.4 and will be about 15.5 arcminutes from Venus. FGS PMT can tolerate and return to normal performance. Goodrich assessed PMT damage should a worst-case event occur resulting in an attempted acquisition of Venus with an FGS (ref: Goodrich Memo A16-ST-2254) Goodrich reports the short-term effect of the Venus acquisition would be the temporary incapacitation of the PMTs due to dark count elevation. While the exact value is not available for the given intensity, literature quotes range from several to 48 hours for recovery (for any target). Goodrich performed a relative assessment of the long-term effects of Coulomb draw (charge depletion) while attempting to acquire Venus with an FGS. While it is hard to determine exactly how the FGS would behave if it attempted to perform an acquisition on Venus, depending on how long it spends with Venus in the FOV, you could see a decrease in reliability from 1-3%.

16. 2010/2011 Venus Observation P. 16 22 Dec 2010 HST FOV

17. 2010/2011 Venus Observation P. 17 22 Dec 2010 HST in the Sun Concern While slewing away from Venus, HST will be exposed to sunlight and pointed inside the SAZ for up to 3m 2s. HST’s maximum previous exposure to sunlight while pointed inside the SAZ was 2m 30s (2003 observation). Pointing inside the SAZ while HST is in sunlight can be tolerated for at least 15 minutes before the temperature of the paint inside the OTA would become a contamination issue. (EM-MOSES-1267 and EM-MOSES-1268) TCS has analyzed limits and has confirmed duration can be tolerated. Precautions Guide star search radius was reduced in order to save 10-30 seconds of acquisition time.

18. 2010/2011 Venus Observation P. 18 22 Dec 2010 HST Safing Concern HST must not enter inertial hold safe mode while pointed within the SAZ. Precautions Modifying the inertial hold safe mode response such that any condition that would normally lead to inertial hold without closing the AD leads to software sun point safe mode instead. This was done in both prior HST observations of Venus.

19. 2010/2011 Venus Observation P. 19 22 Dec 2010 2010 Venus Observations GSACQ Adjustments Mike Wenz for Merle Reinhart

20. 2010/2011 Venus Observation P. 20 22 Dec 2010 GSACQ Adjustments Idea is to compress the time allowed for the single-star GSACQs to minimize the time in sunlight within 50° of the sun and/or provide more science exposing time. Obvious places for a time compression are Spiral Search time Move back to the target attitude (GS Offset via #43 command) STIS will ignore the TDF via special commanding. Thus, need to ensure if the GSACQ fails, that we are back at the target attitude for the science exposure. This implies a reasonable setting of the AQEXPIRE timer in the SMS call to the GSACQ PLCP.

21. 2010/2011 Venus Observation P. 21 22 Dec 2010 GSACQ Time Reduction Specifics – Dec Visit: Orbits 0 & 1 Orbit #0 OBAD with Trackers 1 & 3 Tracker 2 is explicitly avoided due to Capella (mag 0.08) being on the edge of the field and a fairly bright variable star (mag 1.81) being in the field Orbit #1 OBAD with Trackers 1 & 3 immediately prior to single-star gsacq Assumed error after the OBAD at the start of the gsacq is 20” PCS indicates nominal post-OBAD error is 10-12”, but 20” is used to be conservative Time for spiral search = 32s (-40s) At the target position, the guide star is <1” from the pickle centerline Time for 21” decenterline maneuver = 32s (-23s) However, since we are telling STIS to ignore the TDF for these observations, we want to set AQEXPIRE to prior to start of Track51 slew Thus likely get data even if the gsacq fails Time for AQEXPIRE to fire and complete is 35s 27s for maneuver + 8s for other overheads Final GSACQ time = 344s + (-40s + -23s + 35s) = 316s AQEXPIRE value = 316s – 35s – 3s = 278s The -3s is the AQEXPIRE timer isn’t enabled until 3s into the PLCP

22. 2010/2011 Venus Observation P. 22 22 Dec 2010 GSACQ Time Reduction Specifics – Dec Visit: Orbit #2 Orbit #2 OBAD with Trackers 1 & 3 immediately prior to single-star gsacq Assumed error after the OBAD at the start of the gsacq is 20” Time for spiral search = 32s (-40s) At the target position, the guide star is 52” from the pickle centerline Time for 72” decenterline maneuver = 49s (-6s) However, since we are telling STIS to ignore the TDF for these observations, we want to set AQEXPIRE to prior to start of Track51 slew Time for AQEXPIRE to fire and complete is 52s 44s for maneuver + 8s for other overheads Final GSACQ time = 344s + (-40s + -6s + 52s) = 350s AQEXPIRE value = 350s – 52s – 3s = 295s The AQEXPIRE changes are done as an SMS Edit. If edit were to not occur, the only effect would be if the GSACQ failed, the spacecraft would not be maneuvered back to the target position prior to the initiation of the Track51 for the exposure.

23. 2010/2011 Venus Observation P. 23 22 Dec 2010 2.0 FSW, S/C H/W Changes and Implementation FSW – Brian Vreeland

24. 2010/2011 Venus Observation P. 24 22 Dec 2010 2.0 FSW, S/C H/W Changes and Implementation 2.1 FSW and/or S/C H/W Functional Changes Venus Observation SPC Macros (DCR 1552) Load File – QVENUS0_0.TAB Contains 2 Macros Activation Macro at SPC Address 19824 (Jump Table Addr 1) Perform BMIC management for the modified Tables Modify the Sunpoint Sun Cosine Limit from 46 to 42 degrees Modify six Safe Test Responses from Inertial Hold to Software Sunpoint (w/o Load Shed) SBREHE - High Mode Body Rate Error SSPCLEXE – SPC List Exhaust SBMICE - BMIC SEMBOPE - Earth-Moon Protection SMHGATCT - HGA Torque Limit SNELEAKE - Neon Leak tests Other Inertial Hold Test Responses Close AD in addition to IH and are not changed in macro SPSEAPSE - PSEA Power Supply Failure SSUNAPRE - Sun Aperture SSBOPE - Sun Bright Object Protection Thermally safe if Aperture door is closed and HST is at 46 degress

25. 2010/2011 Venus Observation P. 25 22 Dec 2010 2.0 FSW, S/C H/W Changes and Implementation 2.1 FSW and/or S/C H/W Functional Changes (cont…) Restoration Macro at SPC Address 19825 (Jump Table Addr 2) Perform BMIC management for the modified Tables Restore the Sunpoint Sun Cosine Limit from 42 to 46 degrees Restores six Safe Test Responses from Software Sunpoint to Inertial Hold Installation and Usage Procedure “IP-219_Venus_Observation_Macros.docx” 3 Sections Load, Dump and Compare QVENUS0_0.TAB, to verify the load Execute the Activation Macro as required Execute Restoration Macro as required

26. 2010/2011 Venus Observation P. 26 22 Dec 2010 2.0 FSW, S/C H/W Changes and Implementation 2.2 FSW Structure/Resource Changes – None 2.3 Supporting Ground System Changes - None 2.4 Supporting Documentation Changes - None 2.5 Release Messages SSM212 IP-219_Venus_Observation_Macros.docx PNM_20103473812.TXT 2.6 Unit and Build Level Testing/Results None Needed

27. 2010/2011 Venus Observation P. 27 22 Dec 2010 2.0 FSW, S/C H/W Changes and Implementation 2.7 System Level Testing/Results Software Simulation Environment 8 FVS tests run to verify proper configuration after macro execution VENOBS1 – Venus Observation Test 1 - Nominal Case VENOBS2 – Venus Observation Test 2 - SPC List Exhaustion VENOBS3 – Venus Observation Test 3 - BMIC Failure VENOBS4 – Venus Observation Test 4 - High Body Rate Error VENOBS5 – Venus Observation Test 5 - Earth/Moon Protection Error VENOBS6 – Venus Observation Test 6 - HGA Torque Limit VENOBS7 – Venus Observation Test 7 - Sun Cosine Limit VENOBS8 – Venus Observation Test 8 - Neon Leak Case Verified that Software Sunpoint commanded versus Inertial Hold Hardware Test Environment Lab Configuration CCS 7.1.1.0.4 / PRD O07300R1S PCSSIM 51A On-Orbit Patches Installed Gyro 3-4-5 Installation Procedure Verification using VSSNOR and IP Completed in LMB

28. 2010/2011 Venus Observation P. 28 22 Dec 2010 2.0 FSW, S/C H/W Changes and Implementation 2.8 H/W Interfaces Impact & Verification Matrix N/A 2.9 CPM2 & 3 Update Recommendation N/A

29. 2010/2011 Venus Observation P. 29 22 Dec 2010 3.0 Engineering Test / Installation 3.1 Overview and Initial Conditions SSM486 Flight Software Version 3.4 or higher and currently executing in VSS with H-format programmable telemetry enabled 3.2 Script Review Section A – Load, dump, compare Venus Observation SPC Macro Table Load Load Venus Observation SPC Macro Table load (1 min) Dump the SPC table 1 (5 min) Compare the Venus Observation SPC Macros Table with the dump (1 min) Section B – Venus Observation Macro Activation Activate Venus Observation Macro 1 (1 min) Section C – Venus Observation Restoration Verify Special Processor not active (1 min) Activate post Venus Observation Macro 2 ( 1min)

30. 2010/2011 Venus Observation P. 30 22 Dec 2010 3.0 Engineering Test / Installation 3.3 Standalone Testing Objective To validate Venus macro installation and back-out procedure in an operational scenario without impact to operations. The Standalone Testing was performed using STScI- provided test SMS. DSTIF Test Bed Configuration DMU (only one), DIUs (test configuration), CPM2 PCS Simulator, Version 51A 486 FSW Configuration (current on-orbit) FSW 3.4A installed BMIC enabled Telemetry ‘H’ Format Safemode tests and macros enabled for the SMS testing CCS Ground Test Configuration Ground System Software – CCS Version 7.1.1.0.4 Database – O07300R1S

31. 2010/2011 Venus Observation P. 31 22 Dec 2010 3.0 Engineering Test / Installation 3.3 Standalone Testing (continued) The STScI generated test SMS was run twice. Executed IP-219, Venus Observation SPC Macros, to patch the Safemode Responses and change the Sun Cosine Limit to support the Venus Observation During the first run of the SMS, the acquisitions were allowed to complete nominally. All of the acquisitions performed as expected. During the second run of the SMS, the acquisitions were forced to run long in the PCS Simulator to allow the AQEXPIRE timer to fire off. The setting of the AQEXPIRE parameter in the GSACQ blocks was verified to be long enough to allow enough time for the acquisitions to stop and maneuver the vehicle to the Target attitude before the Moving Target tracking slews were commanded. Executed IP-219, Venus Observation SPC Macros, to back out the Macro changes. If the AQEXPIRE command fires off while the #43 (Vehicle Offset Maneuver) command is being executed a Command Reject will occur. This is the same situation detailed in Ops Note 1973. It takes a very unique failure case for this to occur. The Vehicle will be at the correct target location if this happens and there are no Health and Safety concerns. The acquisition will terminate correctly.

32. 2010/2011 Venus Observation P. 32 22 Dec 2010 3.0 Engineering Test / Installation STIS Venus Observations Test SMS (STISITDF) was generated and delivered to the SISE to validate special commanding and confirm the CCD observations with the TDF response disabled, allowing the exposure to continue regardless of the results of the GSAcq All external CCD exposures are normally taken with TDF response enabled. Test SMS was executed on VSTIF on 12-2-10 NSSC-1 FSW BQ 9.0.8 STIS FSW CS5.01/MIE4.4 (ov0008)CS5.01/MIE4.4 Bus monitor tool enabled for logging STIS Ops Benches in Safe mode prior to test start SMS was executed twice, once with TDF enabled and once with TDF disabled SMS transitioned STIS from Safe to Operate and then performed two CCD images. One with TDF response disabled and one with TDF Response Enabled. CCD Images were then dumped and headers reviewed to verify CCD Shutter performance.

33. 2010/2011 Venus Observation P. 33 22 Dec 2010 3.0 Engineering Test / Installation STIS Venus Observations Summary STIS CCD Shutter opens and closes normally regardless of TDF state when TDF response in disabled. Additional manual testing of STIS CCD shutter response to TDF state toggling while exposure in progress was also performed. CCD Shutter remained open.

34. 2010/2011 Venus Observation P. 34 22 Dec 2010 3.0 Engineering Test / Installation 3.4 Timeline Review 1 st Opportunity to load Venus Observation Macros @ 356/20:28 – 20:55 2 nd Opportunity to load Venus Observation Macros @ 356/21:56 – 22:37 1 st Opportunity to activate Macro 1 @ 361/19:40 – 19:56 2 nd Opportunity to active Macro 1 @ 361/21:36 – 22:01 Slew to Venus+5º starts at 361/22:30 Slew away from the Venus activities starting at 362/02:03 1 st Opportunity to restore via Macro 2 @ 362/02:35 – 02:42 2 nd Opportunity to restore via Macro 2 @ 362/03:35 – 03:40

35. 2010/2011 Venus Observation P. 35 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review PLACE HOLDER 1 st opportunity to load Venus Observation Macros

36. 2010/2011 Venus Observation P. 36 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review 2 nd opportunity to load Venus Observation Macros 1 st op. for NCCI load

37. 2010/2011 Venus Observation P. 37 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review 1 st opportunity to Activate Macro 1

38. 2010/2011 Venus Observation P. 38 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review 2 nd opportunity to Activate Macro 1

39. 2010/2011 Venus Observation P. 39 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review

40. 2010/2011 Venus Observation P. 40 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review

41. 2010/2011 Venus Observation P. 41 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review 1 st opportunity to execute restore macro 2 2 nd opportunity to execute restore macro 2

42. 2010/2011 Venus Observation P. 42 22 Dec 2010 3.0 Engineering Test / Installation – MEGG review

43. 2010/2011 Venus Observation P. 43 22 Dec 2010 4.0 Monitoring and System Impacts 4.1 On-Orbit Validation / Monitoring DMS will validate successful load of the (safemode) configuration macro PCS will monitor OBAD acq PI will validate data prior to Jan observations 4.2 System Impacts PCS, SI, EPS: None DMS, I&C Mat LEI turned off for a 9 hour window THERMAL: Waiver of CARD 3.1.7.3 (see Section 5.1) SAFING: Temporary modification to responses of six safemode tests In FSW, reducing the Sunpoint Sun protection threshold limit to provide margin for Venus Observation PSEA BOD circuitry provides redundancy against Sun in the boresight within 38º

44. 2010/2011 Venus Observation P. 44 22 Dec 2010 4.0 Monitoring and System Impacts 4.3 Supporting Operations Changes None 4.4 Supporting PRD Changes None 4.5 Subsystem Training Module Changes None

45. 2010/2011 Venus Observation P. 45 22 Dec 2010 5.0 Constraints and Restrictions Review 5.1 CARD One waiver is required: 3.1.7.3 HST Sun Pointing Limits The HST sun angle as measured from the +V1 axis should not go below 50°. Excursions could raise the OTA baffle temperatures above their bake-out temperatures and out-gassing may result. 46° is required for the Venus observation EM MOSES 1067 outlines the thermal impacts to prolonged sun angles <50° A nominal Venus Observation as outlined here should not violate any temperature limits An inertial hold safemode at sun angles <50° has the potential to violate OTA baffle temperature limits All contingency procedures comply with the CARD 5.2 OLD No operations limitations violated or waivers required in the procedures All activities for installation handled by FSW code design and procedure

46. 2010/2011 Venus Observation P. 46 22 Dec 2010 6.0 Contingency Planning 6.1 Vehicle Contingencies HST safing while pointed within the SAZ Concern If HST were to enter inertial hold safe mode while pointed within the SAZ, that could violate thermal temperature limits on the OTA baffles After 15 minutes in sunlight at 46° sun angle the OTA baffles exceed their 121°C bake-out temperature limit (EM MOSES 1067) Precautions Redirecting certain safemode tests such that conditions that would normally lead to inertial hold leads to software sun point safe mode instead to prevent Sun in boresight CDH Safing event Still activate observation macro Allow SMS to continue No observation

47. 2010/2011 Venus Observation P. 47 22 Dec 2010 6.0 Contingency Planning 6.1 Vehicle Contingencies FGS exposure to Venus Concern If the attitude error is large enough, an FGS could possibly see Venus and cause potential bright light exposure to the FGS photo-multiplier tubes. Precautions Choose guide stars that are as far as possible from Venus The chosen guide star is magnitude 12.4 and will be about 15.5 arcminutes from Venus

48. 2010/2011 Venus Observation P. 48 22 Dec 2010 6.0 Contingency Planning 6.1 Vehicle Contingencies FGS exposure to Venus Analysis Goodrich assessed PMT damage should a worst-case event occur resulting in an attempted acquisition of Venus with an FGS (ref: Goodrich Memo A16-ST-2254) Goodrich reports the short-term effect of the Venus acquisition would be the temporary incapacitation of the PMTs due to dark count elevation. While the exact value is not available for the given intensity, literature quotes range from several to 48 hours for recovery (for any target). Goodrich performed a relative assessment of the long-term effects of Coulomb draw (charge depletion) while attempting to acquire Venus with an FGS. While it is hard to determine exactly how the FGS would behave if it attempted to perform an acquisition on Venus, depending on how long it spends with Venus in the FOV, you could see a decrease in reliability from 1-3%. Response If SEs determine that there is a large attitude error, Software Sunpoint may be commanded via COP 6.01

49. 2010/2011 Venus Observation P. 49 22 Dec 2010 6.0 Contingency Planning 6.1 Vehicle Contingencies Code Red GSFC Inclement Weather Situation Venus observation will be executed from SMS If potential weather situation is predicted, an early execution of the configuration macro will be performed during good weather If sudden storm occurs, SEs will make best effort to support from OSR or via phone

50. 2010/2011 Venus Observation P. 50 22 Dec 2010 7.0 Engineering Support Requirements 7.1 Personnel Test Conductor – DMS Ben Teasdel FSW- Briand Vreeland Systems Management- Wayne Burdick STIS Steve Arslanian PCS Dan Smith Normal SE on-call personnel FOT - normal shift 7.2 Communications / Data FOT will be briefed before the test. Circuit assignments: R/T Ops COORD Primary circuit for Test Conductor and FOT HST COORD Backup loop to FOT Ops Requests (OR’s) 18990-4 – “Load Venus Observation Macros” 18991-1 – “Venus Observation Patch” Flash Reports will be issued following completion of the test. FRR Material is available on EDOCS web site http://edocs.hst.nasa.gov/MOP/Shared%20Documents/FRRpage.htm

51. 2010/2011 Venus Observation P. 51 22 Dec 2010 7.0 Engineering Support Requirements 7.3 CCS Prime Ops on “F” string Back-up Ops on “D” string CCS Release 8.1.0.0.14 PRD O07300R1S FSW loads have been delivered to both prime and back-up strings

52. 2010/2011 Venus Observation P. 52 22 Dec 2010 8.0 Liens/Issues None

53. 2010/2011 Venus Observation P. 53 22 Dec 2010 9.0 Forward Plan Ops Briefing Jan 19 th PI to analyze data from December observation prior to this briefing to ensure observation was successful and enable refinements of January observation to improve data gathering.

54. 2010/2011 Venus Observation P. 54 22 Dec 2010 10.0 Actions

55. 2010/2011 Venus Observation P. 55 22 Dec 2010 Backup Information

56. 2010/2011 Venus Observation P. 56 22 Dec 2010 Target Visibility GS Pair Acq at Venus+5D Slew to Venus Target Visibility Shadow Single GS Acq at Venus Observe Venus Slew to Venus+5D Observe Venus+5D GS Pair Acq at Venus+5D Observing Strategy Details Target Visibility Shadow Slew to Venus Single GS Acq at Venus Observe Venus Slew to Venus+5D Observe Venus+5D GS Pair Acq at Venus+5D –Display as seen from HST

57. 2010/2011 Venus Observation P. 57 22 Dec 2010 –Sun –Venus –Earth HST’s View of Venus (t = 0) –Venus is in Earth occultation. The Sun is not. HST would be pointed at Venus+5D at this time. –Sun –Venus –Venus+5D –Earth –Sun –Venus –Venus+5D –Earth

58. 2010/2011 Venus Observation P. 58 22 Dec 2010 HST’s View of Venus (t = 5 min) –The Sun is moving toward setting.

59. 2010/2011 Venus Observation P. 59 22 Dec 2010 HST’s View of Venus (t = 10 min) –The Sun is moving toward setting. The terminator becomes visible on the Earth.

60. 2010/2011 Venus Observation P. 60 22 Dec 2010 HST’s View of Venus (t = 15 min) –The Sun is very close to setting.

61. 2010/2011 Venus Observation P. 61 22 Dec 2010 HST’s View of Venus (t = 20 min) –The Sun has set. HST is now in the Earth’s shadow.

62. 2010/2011 Venus Observation P. 62 22 Dec 2010 HST’s View of Venus (t = 25 min) –Venus is very close to rising. At about this time, HST will begin its slew from Venus+5D to Venus

63. 2010/2011 Venus Observation P. 63 22 Dec 2010 HST’s view of Venus (t = 30 min) –Venus has risen. At about this time, HST will complete its slew to Venus; and the guide star acquisition will begin.

64. 2010/2011 Venus Observation P. 64 22 Dec 2010 HST’s View of Venus (t = 35 min) –At about this time, the guide star acquisition will finish; and the science observation will begin.

65. 2010/2011 Venus Observation P. 65 22 Dec 2010 HST’s View of Venus (t = 40 min) –At about this time, the science observation will finish; and the slew to Venus+5D will begin.

66. 2010/2011 Venus Observation P. 66 22 Dec 2010 HST’s View of Venus (t = 45 min) –The Sun is very close to rising.

67. 2010/2011 Venus Observation P. 67 22 Dec 2010 HST’s View of Venus (t = 50 min) –The Sun has risen. HST is now out of the Earth’s shadow. The slew to Venus+5D finishes a couple of minutes after sunrise.