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Flight Readiness Review (FRR): Venus Proposal 13047

Flight Readiness Review (FRR): Venus Proposal 13047. October 16, 2013. Agenda. 1.0 Engineering Team. 2.0 Introduction / Overview. 2.1 Objective

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Flight Readiness Review (FRR): Venus Proposal 13047

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  1. Flight Readiness Review (FRR):Venus Proposal 13047 October 16, 2013

  2. Agenda

  3. 1.0 Engineering Team

  4. 2.0 Introduction / Overview 2.1 Objective • Perform observations associated with Venus Proposal 13047 – “The D/H Ratio and Escape of Water from Venus” (PI: Clarke) near the point of maximum eastern elongation, and load and execute HST486 FSW macros bounding the observations. 2.2 Statement of Adherence to AD2-16 & AD2-17 • Testing and preparation for Venus Proposal 13047 followed the guidelines of: • AD 2-16 – “Operations Acceptance Testing” • AD 2-17 – “Spacecraft Configuration Change Process”

  5. 2.0 Introduction / Overview 2.3 Background • Objectives • Explain Venus observing strategy • Review areas of special concern with Venus observations and explain how these concerns are being addressed • Determine if implementation is correct and complete • Why is Venus Special? • At its maximum separation, Venus gets to be about 47° from the Sun • HST is normally not permitted to point within 50° of the Sun(Restriction 3.1.7.3) • Scientific Goals • Measure Lyman-alpha emissions from deuterium and from hydrogen in order to determine the D/H ratio in the upper atmosphere • To help distinguish between terrestrial and Venusian Lyman-alpha, observations should happen when the Doppler shift from the combined line of sight orbital motions of Venus and the Earth is maximized • The Doppler shift requirement results in observing during the 2013 eastern elongation

  6. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Observing Strategy • Observe while Venus is near maximum elongation • 4 visits of 1 orbit each • Observe while HST is in Earth’s shadow • A window of 13-16 minutes per orbit • Observe sky background near (~7°) from Venus but within HST’s normal field of regard (i.e., >50°) • 2 visits of 1 orbit each • The visits may be scheduled in 6 consecutive orbits, but being consecutive is not required

  7. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Observing Strategy Details • Visits currently scheduled on October 24, 2013 • Scheduled in 6 consecutive orbits • Order • Visit 03 – sky background • Visit 01 – Venus • Visit 02 – Venus • Visit 05 – Venus • Visit 06 – sky background • Visit 04 – Venus

  8. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Observing Strategy Details (Cont’d) • Initial GS Acq at Venus+7° • A pointing 7° from Venus and 53.6° from the Sun • Minimizes slew distance to Venus • Precautionary measure to protect against large pointing error after slew • Provides additional sky background data Target Visibility Shadow GS Pair Acqat Venus+7° Slew to Venus Observe Venus Gyro Acq at Venus+7° Observe Venus+7° Single GS Acq at Venus Slew to Venus+7°

  9. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Observing Strategy Details (Cont’d) • Single GS Acq at Venus • Saves about a minute versus pair acquisition • Venus science observation • One 300s exposure • STIS auto wave cal disabled Target Visibility Shadow GS Pair Acqat Venus+7° Slew to Venus Observe Venus Gyro Acq at Venus+7° Observe Venus+7° Single GS Acq at Venus Slew to Venus+7°

  10. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries • STIS 52x0.5 Slit on Venus in Visit 01

  11. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=0)

  12. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=0) (Cont’d) • Bodies that are relevant to this observing program Sun Venus Venus+7D

  13. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=0) (Cont’d) • Other bodies that happen to be appear in this view Pluto Mercury Saturn & moons

  14. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=0) (Cont’d) • At about this time, HST is beginning its slew from Venus+7D to Venus

  15. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=5m) • Slew to Venus is continuing. Sun is about to set. terminator Earth

  16. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=10m) • Sun has set. Slew to Venus is complete. GS Acq. is in progress.

  17. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=15m) • Science observation is beginning

  18. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=20m) • Science observation is continuing

  19. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=25m) • Science observation is complete. Slew away from Venus is in progress.

  20. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Observation CAD Models/Geometries (Cont’d) • HST’s View of Venus (t=30m) • Slew away from Venus is complete. Pointing at Venus+7D with gyro guiding.

  21. 2.0 Introduction / Overview 2.3 Background (Cont’d) • Venus Appearance at Observation • Apparent V magnitude: -4.5 ± 0.3 • Apparent diameter: 23.0” • Phase angle: 86.3° • STIS Bright Object Screening • Observations will use STIS E140H Cenwave=1234 Å with 52x0.5 aperture • Allowed count rate screening limits • No more 200,000 counts/second global rate • No more than 75 counts/pixel/second locally

  22. 2.0 Introduction / Overview 2.3 Background (Cont’d) • STIS Bright Object Screening (Cont’d) • Expected count rates • Previous observations with other satellites give Venus Lyman-alpha surface brightness of ~20 kR = 6e-13 ergs/cm2/s/arc-sec2 with line width of ~1 Å • ETC calculation (STIS.sp.538741) for 0.2x0.2 aperture predicts only4 c/s global rate from source and 0.02 c/p/s local • Scaling to 0.5” wide slit x 12” (half illuminated disk of Venus) yields a predicted global rate of 625 c/s with peak local rate of ~0.05 c/p/s • January 2003 Venus observations from Program 8069 using E140H Cenwave=1234 Å with 0.2x0.09 aperture saw only 0.25 c/s from combined geo-coronal + Venusian Lyman-alpha • No evidence of any continuum spectrum from Venus was visible • Current program will observe 12”x0.5” area of illuminated disk (~350x larger) which would give only 100 c/s global count rate if scaled from the smaller aperture used by the earlier program • The small area of the aperture used by Program 8069 may well have missed localized emission • Comparison between expected vs. allowed count rates • 625 c/s global << 200,000 c/s allowed global screening rate • 0.05 c/p/s local rate << 75 c/p/s allowed local screening rate

  23. 2.0 Introduction / Overview 2.3 Background (Cont’d) • STIS Bright Object Screening (Cont’d) • Also need to check for bright background objects • O5 star with V=10 would be close to allowed global limit of 200,000 c/s • When comparing with the field, the parallax effects due to HST’s orbital motion need to be included • Shift in position over HST orbit similar to the angular size of Venus (~23”) • Procedure: • The program coordinator provided to the instrument scientist with HST-centric ephemerides for both the Venus and Venus-OFFSET-7D target pointings • Current bright object tool was used to check fixed pointings spaced at 10 min intervals along the target path to clear the region swept out by the MAMA observations

  24. 2.0 Introduction / Overview 2.4 On-orbit History • In 1995, Proposals 4518 (PI: Esposito) and 5783 (PI: Esposito) performed Goddard High Resolution Spectrograph (GHRS) and Wide Field Planetary Camera 2 (WFPC2) observations of Venus near maximum western elongation. • In 2003, Proposal 8659 (PI: Bullock) performed STIS observations of Venus near maximum western elongation. • In December 2010/January 2011, Proposal 12433 (PI: Jessup) performed STIS CCD observations of Venus near maximum western elongation • These October 2013 Proposal 13047 (PI: Clarke) STIS MAMA observations are near maximum eastern elongation

  25. 3.0 FSW, S/C H/W Changes and Implementation 3.1 FSW and/or S/C H/W Functional Changes • Venus Observation SPC Macros (DCR 1637) • Load File – QVENUS0_0.TAB • Contains 2 macros • Venus Observation Macro at SPC Address 17555 (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 Test • Other Inertial Hold test responses close the aperture door (AD) in addition to IH and are not changed in macro (HST is thermally safe if the AD is closed and Sun angle is 46 degrees) • SPSEAPSE – PSEA Power Supply Failure • SSUNAPRE – Sun Aperture • SSBOPE – Sun Bright Object Protection

  26. 3.0 FSW, S/C H/W Changes and Implementation 3.1 FSW and/or S/C H/W Functional Changes (Cont’d) • Venus Observation SPC Macros (DCR 1637) (Cont’d) • Post-Venus Observation Macro at SPC Address 17601 (Jump Table Addr 2) • Perform BMIC management for the modified tables • Restore the Sunpoint Sun Cosine Limit from 42 to 46 degrees • Restore six safe test responses from Software Sunpoint to Inertial Hold • Installation and Usage Procedure“IP-248_Venus_Observation_Macros.docx” • 3 Sections • Load, dump and compare QVENUS0_0.TAB, to verify the load • Execute the Venus Observation Macro as required • Execute Post-Venus Observation Macro as required

  27. 3.0 FSW, S/C H/W Changes and Implementation 3.2 FSW Software Structure/Resource Changes • None. 3.3 CPM2 & 3 Update Recommendation • N/A 3.4 Supporting Ground System Changes • None. 3.5 Supporting Documentation Changes • None. 3.6 Release Messages • SSM232 • IP-248_Venus_Observation_Macros.docx • PNM_2013262192058.TXT

  28. 4.0 Testing and Verification 4.1 Unit and Build Level Testing/Results • 1 FVS Test – List Exhaust with response changed to SWSP by the macro and Sun Protection Test fails with modified limit, closing the aperture door • Macro contents verified by inspection • Macros use the same symbols but with Venus and restored values, respectively 4.2 System Level Testing/Results • Software Simulation Environment • 2 FVS tests were run to verify the proper configuration after macro execution • VENOBS1 – Venus Observation Test 1 – Nominal Case • VENOBS2 – Venus Observation Test 2 – SPC List Exhaustion • Tested that Software Sunpoint is commanded versus Inertial Hold • Hardware Test Environment • Lab Configuration • CCS 8.3.0.0.23 / PRD D07756S • PCSSIM 54A • On-Orbit patches installed • Gyro 6-4-5 • Installation Procedure Verification using VSSNOR and IP-248 • Completed in 486 Lab

  29. 4.0 Engineering Test / Installation 4.3 FSW/Operations Acceptance Testing, TSAR Status and Results • VEST Configuration for October 3, 2013 (Day 276): • Ground system software – CCS Version 8.4.0.0.12 • CCS string – H Test • Database – PRD-O07700ST • Quick update of QFSW37ARAM2.tcl proc applied • NSSC-1/CDH2 FSW 9.2.2 • STIS Ops Bench • PSEA • SSR-1 • PCS SIM Version 54A • 486 FSW Configuration (current on-orbit) • FSW 3.7A installed • BMIC enabled • KA enabled • Telemetry format HN • Safemode tests and macros enabled

  30. 4.0 Engineering Test / Installation 4.3 FSW/Operations Acceptance Testing, TSAR Status and Results (Cont’d) • Test Sequence: • Executed IP-248 – “Venus Observation Macros Installation and Usage Procedure”, Section A to load, dump, and compare the Venus Observation SPC Macros • Executed IP-248 – “Venus Observation Macros Installation and Usage Procedure”, Section B to activate Macro 1 (i.e., the Venus Observation Macro) • Modifies six safe test responses from Inertial Hold to Software Sunpoint • Changes the Sun Cosine Limit from 46° to 42° • Monitored Venus Observation • All guide star acquisitions performed as expected • STIS observations were both recorded and collected in real-time for Payload FSW verification of timestamps within science data headers • Executed IP-248 – “Venus Observation Macros Installation and Usage Procedure”, Section C to activate Macro 2 (i.e., the Post-Venus Observation Macro) • Restores safe test responses and the Sun Cosine Limit to their nominal values

  31. 4.0 Engineering Test / Installation 4.3 FSW/Operations Acceptance Testing, TSAR Status and Results (Cont’d) • HSTAR and TSAR Status

  32. 4.0 Engineering Test / Installation 4.3 FSW/Operations Acceptance Testing, TSAR Status and Results (Cont’d) • HSTAR and TSARs did not prevent the execution of the test script or impact the test results • Summary • The Venus Observation Macros loaded and executed as expected • No operations procedures were modified as a result of the test • The SMS executed successfully through the Venus visit • No significant changes to stored commanding or proposals were required • Attitude for Venus observation was as expected • Exposure timing was as expected • Payload FSW verified timestamps within the headers of the dumped STIS MAMA images

  33. 4.0 Testing and Verification 4.4 H/W Interfaces Impact & Verification Matrix • HST486 FSW 4.5 Testing Liens and Limitations • The Venus observation attitudes are hot for the telescope baffles since the +V1 axis is pointed ~46.8° away from the Sun • Hardware temperatures are not modeled within the test environment • TCS has completed their analysis of the observing plan and has confirmed that the light shield baffle temperatures will remain well below the 300°F threshold cited within Constraint 2.2.1.7 – “OTA Light Shield Baffle Thermal Limits” (email dated September 17, 2013)

  34. 4.0 Engineering Test / Installation 4.6 Differences Between Test and Flight Configurations • No NSSC-1 FSW image was loaded in the HST486 • There was no need to reload the NSSC-1 FSW during the test • No impact • The test SMS contained only two acquisitions for one Venus visit to be used in the operational SMS (i.e., a pair acq. and an associated single star acq.) • The four Venus visits are effectively identical with only slight differences in the pre-Venus background exposure times and the positions of Venus itself • The two background visits are typical STIS MAMA observations • No impact

  35. 5.0 Operations Activities/ Installation 5.1 Overview and Initial Conditions • SSM486 Flight Software Version 3.7A or higher is installed and executing in VSS with H-format programmable telemetry enabled • Load and execute the Venus Observation macros bounding the Venus visits 5.2 Ops Request and Script Review • Section A – Load, dump, compare Venus Observation SPC Macro Table Load • Load Venus Observation SPC Macro Table load (1 min) • Dump SPC Table 1 (5 min) • Compare the load and dump images (1 min) • Section B – Venus Observation Macro Activation • Activate Venus Observation Macro (i.e., Macro 1) (1 min) • Monitor Venus observations • Section C – Venus Observation Restoration • Verify special processor not active (1 min) • Activate Post-Venus Observation Macro (i.e., Macro 2) (1 min)

  36. 5.0 Operations Activities/ Installation 5.3 Summary of SMS Observing Plans • GS Acq. Adjustments • Visit 03 – sky background • 297/11:24:50 – Pair: No Changes • Visit 01 – Venus • 297/12:46:52 – Pair: No Changes • 297/13:28:18 – Single: AQEXPIRE from 780s to 1800s • Visit 02 – Venus • 297/14:19:18 – Pair: Allow for 55” search due to suppressed OBAD • 297/15:03:41 – Single: AQEXPIRE from 780s to 1800s • Visit 05 – Venus • 297/15:55:28 – Pair: No Changes • 297/16:39:15 – Single: AQEXPIRE from 780s to 1800s • Visit 06 – sky background • 297/17:30:48 – Pair: No Changes • Visit 04 – Venus • 297/19:06:51 – Pair: No Changes • 297/19:51:09 – Single: AQEXPIRE from 780s to 1800s • The AQEXPIRE changes ensure that the timer will expire well after the timer’s termination by the PCPTERM at the start of the slew away from Venus • This prevents any possibility of the GSACQ failing and the expire timer stepping on the activities to slew away from Venus

  37. 5.0 Operations Activities/ Installation 5.4 Timeline Review • Operations Request 19500 – “Venus Observation” • Start time 297/11:03 UTC (October 24 @ 7:03 am. EDT) • Load, dump and compare Venus SPC macros and activate Macro 1 • First opportunity @ 297/11:03 – 11:33 • Second opportunity @ 297/11:45 – 12:36 • Third opportunity @ 297/12:38 – 13:12 • Last slew out from Venus @ 297/20:12 • Activate Macro 2 • First opportunity @ 297/20:16 – 21:08 • Second opportunity @ 297/21:19 – 21:39 • Third opportunity @ 297/22:00 – 22:50

  38. 5.0 Operations Activities/ Installation GS Pair Acq @ Venus +7d 1stop. to load, dump and compare SPC macro & Activate Macro 1 2ndOpportunity

  39. 5.0 Operations Activities/ Installation Single GS Acq @ Venus GS Pair Acq @ Venus +7d 1st slew inside of the 50d SAZ 3rdOpportunity

  40. 5.0 Operations Activities/ Installation Single GS Acq @ Venus GS Pair Acq @ Venus +7d GS Pair Acq @ Venus +7d

  41. 5.0 Operations Activities/ Installation Single GS Acq @ Venus GS Pair Acq @ Venus +7d

  42. 5.0 Operations Activities/ Installation Single GS Acq @ Venus GS Pair Acq @ Venus +7

  43. 5.0 Operations Activities/ Installation 1st op. to activate Post-Venus Observation macro 2 2nd Opportunity

  44. 5.0 Operations Activities/ Installation 3rd Opportunity

  45. 6.0 Monitoring and System Impacts 6.1 On-Orbit Validation / Monitoring • DMS and FSW will validate the successful load of the macros • DMS will verify macro execution 6.2 System Impacts • DMS/I&C – MAT LEI suspended from 297/11:00 to 22:52 UTC • OTA – • GS Acq. parameters modified for Venus visits • OTA signoff of SMS required • SAF – Temporary modification to responses of six safemode tests and to Sun bright object protection threshold • PSEA BOD circuitry provides hardware protection in the event that the Sun is within 38° of the boresight • TCS – Waiver required for Restriction 3.1.7.3 – “HST Sun Pointing Limits” • STScI – GS Acq. parameters modified for Venus visits • EPS, FOT, FSW, PCS, SI – None • SAMS, HSTGS Development and Response Teams, Test Systems – None • Critical Science Considerations – N/A

  46. 5.0 Monitoring and System Impacts 6.3 Supporting Operation Changes • None. 6.4 Supporting PRD Changes • None. 6.5 Supporting STScI Changes • None. 6.6 Subsystem Training Module Changes • None.

  47. 7.0 Constraints and Restrictions Review 7.1 CARD • No operations constraints or restrictions are violated and no waivers are required during macro installation • All installation activities are handled by FSW installation procedure • Restriction 3.1.7.3 – “HST Sun Pointing Limits” must be waived for execution of the Venus Observation Macro • TCS has completed their analysis of the observing plan and has confirmed that the light shield baffle temperatures will remain well below the 300°F threshold cited within Constraint 2.2.1.7 – “OTA Light Shield Baffle Thermal Limits” (email dated September 17, 2013) • The Sun Cosine Limit is being reduced from 46° to 42° during the Venus observation period to provide ~4° margin relative to the expected 46.8° Sun angles • Constraints 2.4.9.1 – “STIS MAMA Global Bright Object Limits” and 2.4.9.2 – “STIS MAMA Local Bright Object Limits”, although relevant, will not be violated. • Venus is not nearly as bright in the FUV as it is in the Visual • Bright scene detection and the local rate monitor will remain enabled • All contingency procedures comply with the CARD 7.2 OLD • No operations limitations are violated and no waivers are required

  48. 8.0 Contingency Planning 8.1 Vehicle Contingencies • Loss of communication with HST while loading the macros or executing the macros • Continue procedure at next opportunity • SI C&DH safing event • The Venus and Post-Venus observation macros will be loaded and executed as planned • The HST486 SMS will continue to execute • Venus observation science data will not be collected • The SI C&DH will be restored to its nominal state in accordance with established procedures • The STScI may reschedule the observations

  49. 8.0 Contingency Planning 8.1 Vehicle Contingencies • HST safing while pointed within the Solar Avoidance Zone (SAZ) • Concern • If HST were to enter inertial hold safe mode while pointed within the SAZ, Constraint 2.2.1.7 – “OTA Light Shield Baffle Thermal Limits” could be violated • Precautions • Six safe test responses will be temporarily modified from Inertial Hold with the Aperture Door open to Software Sunpoint (w/o load shed) to prevent prolonged Sun exposure • This was done for all prior HST observations of Venus • Three opportunities are planned for execution of Macro 1 prior to the slew into Venus • Macro 1 isn’t executed prior to the first slew into Venus • Concern • The protections mentioned above are not in place • Precautions • Macro 1 will be executed at the next opportunity during the Venus visit period • If the vehicle enters inertial hold inside of the SAZ, then software sunpoint will be manually commanded via COP 6.01 (Ops Request 19497-2 – “CONTINGENCY: Commanding SWSP during Venus Observation”) • MAT LEI has been suspended throughout the Venus visit period

  50. 8.0 Contingency Planning 8.1 Vehicle Contingencies (Cont’d) • HST in the Sun • Concern • While slewing to Venus, HST will be exposed to sunlight and pointed inside the SAZ for up to 0m 55s • HST’s maximum previous exposure to sunlight while pointed inside the SAZ was 3m 12s (Jan 2011) • 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 exceed 250°F and become a contamination issue(EM-MOSES-1067 and EM-MOSES-1268) • TCS evaluated the variables that contribute to hot light shield baffle temperatures for the observing plan and confirmed that the observations pose no threat of contamination from outgassing (email dated September 17, 2013) • Sunlit duration while inside the SAZ is well below the 15 minute outgassing point • Solar intensity is shorter than the previous Venus observation resulting in cooler temperatures • Sun angle is similar to/slightly larger than previous Venus observation

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