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

FRR: Venus Proposal P. 2October 16, 2013 Agenda 1.0Engineering Team(M. Slater) 2.0Introduction/Overview(M. Slater, T. Roman, C. Proffitt) 2.1Objective 2.2Statement of Adherence to AD 2-16 & AD Background 2.4On-Orbit History 3.0FSW, S/C H/W Changes and Implementation (N. Roy) 3.1FSW and/or S/C H/W Functional Changes 3.2FSW Software Structure/Resource Changes 3.3CPM2 & 3 Update Recommendation 3.4Supporting Ground System Changes 3.5Supporting Documentation Changes 3.6Release Messages 4.0Testing and Verification (N. Roy, J. Regalado) 4.1Unit and Build Level Testing/Results 4.2System Level Testing/Results 4.3 FSW/Operations Acceptance Testing, TSAR Status and Results 4.5H/W Interfaces Impact & Verification Matrix 4.4 Testing Liens and Limitations 4.6Differences between Flight and Test Configurations 5.0 Operations Activities/Installation(J. Regalado, M. Reinhart) 5.1Overview and Initial Conditions 5.2Ops Request and Script Review 5.3Summary of SMS Observing Plans 5.4Timeline Review – MEGG 6.0Monitoring and System Impacts(M. Slater) 6.1On-orbit Validation / Monitoring 6.2System Impacts 6.3Supporting Operations Changes 6.4Supporting PRD Changes 6.5Supporting STScI Changes 6.6Subsystem Training Module Changes 7.0Constraints and Restrictions Review (M. Slater) 7.1CARD 7.2OLD 8.0Contingency Planning(M. Slater) 8.1Vehicle Contingencies 8.2Ground Contingencies 9.0Engineering Support Requirements (M. Slater) 9.1Personnel 9.2Communications / Data 9.3CCS Configuration 10.0 Liens/Forward Plan(M. Slater)

FRR: Venus Proposal P. 3October 16, 2013 HST486 FSW S. Benedict S. Duhaney N. Roy Ron Stattel B. Vreeland Payload FSW D. Ehlers C. Hoffman M. Kelly B. Serrano C. Townsley STScIC. Proffitt M. Reinhart T. Roman HITTJ. Atwell S. Bozievich VOCCB. Smith J. Smith Sys Mgmt M. Slater FOTJ. Edwards D. Grimes B. Patel D. Schaible T. Walsh DMS/ I&C J. Regalado S. Sands EPS/ TCS D. Lewis OTAJ. Stock M. Wenz PCS/ SAC E. Kimmer D. Murphy SafingE. Moy SIS. Arslanian E. Graham S. Swain 1.0 Engineering Team

FRR: Venus Proposal P. 4October 16, Introduction / Overview 2.1Objective Perform observations associated with Venus Proposal – “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.Proposal – “The D/H Ratio and Escape of Water from Venus” 2.2Statement of Adherence to AD2-16 & AD2-17 Testing and preparation for Venus Proposal followed the guidelines of: »AD 2-16 – “Operations Acceptance Testing” »AD 2-17 – “Spacecraft Configuration Change Process”

FRR: Venus Proposal P. 5October 16, Introduction / Overview 2.3Background 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 ) 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

FRR: Venus Proposal P. 6October 16, Introduction / Overview 2.3Background (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 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

FRR: Venus Proposal P. 7October 16, Introduction / Overview 2.3Background (Cont’d) Observing Strategy Details »Visits currently scheduled on October 24, 2013 »Scheduled in 6 consecutive orbits »Order 1.Visit 03 – sky background 2.Visit 01 – Venus 3.Visit 02 – Venus 4.Visit 05 – Venus 5.Visit 06 – sky background 6.Visit 04 – Venus

FRR: Venus Proposal P. 8October 16, Introduction / Overview 2.3Background (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 Slew to Venus Gyro Acq at Venus+7° Single GS Acq at Venus Observe Venus Slew to Venus+7° GS Pair Acq at Venus+7° Observe Venus+7°

FRR: Venus Proposal P. 9October 16, Introduction / Overview 2.3Background (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 Slew to Venus Gyro Acq at Venus+7° Single GS Acq at Venus Observe Venus Slew to Venus+7° GS Pair Acq at Venus+7° Observe Venus+7°

FRR: Venus Proposal P. 10October 16, Introduction / Overview 2.3Background (Cont’d) Venus Observation CAD Models/Geometries »STIS 52x0.5 Slit on Venus in Visit 01

FRR: Venus Proposal P. 11October 16, Introduction / Overview 2.3Background (Cont’d) Venus Observation CAD Models/Geometries (Cont’d) »HST’s View of Venus (t=0)

FRR: Venus Proposal P. 12October 16, Introduction / Overview 2.3Background (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 Venus+7D Venus Sun

FRR: Venus Proposal P. 13October 16, Introduction / Overview 2.3Background (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

FRR: Venus Proposal P. 14October 16, Introduction / Overview 2.3Background (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

FRR: Venus Proposal P. 15October 16, Introduction / Overview 2.3Background (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. Earth terminator

FRR: Venus Proposal P. 16October 16, Introduction / Overview 2.3Background (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.

FRR: Venus Proposal P. 17October 16, Introduction / Overview 2.3Background (Cont’d) Venus Observation CAD Models/Geometries (Cont’d) »HST’s View of Venus (t=15m) Science observation is beginning

FRR: Venus Proposal P. 18October 16, Introduction / Overview 2.3Background (Cont’d) Venus Observation CAD Models/Geometries (Cont’d) »HST’s View of Venus (t=20m) Science observation is continuing

FRR: Venus Proposal P. 19October 16, Introduction / Overview 2.3Background (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.

FRR: Venus Proposal P. 20October 16, Introduction / Overview 2.3Background (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.

FRR: Venus Proposal P. 21October 16, Introduction / Overview 2.3Background (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

FRR: Venus Proposal P. 22October 16, Introduction / Overview 2.3Background (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/cm 2 /s/arc-sec 2 with line width of ~1 Å ETC calculation (STIS.sp ) for 0.2x0.2 aperture predicts only 4 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

FRR: Venus Proposal P. 23October 16, Introduction / Overview 2.3Background (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

FRR: Venus Proposal P. 24October 16, Introduction / Overview 2.4On-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 (PI: Jessup) performed STIS CCD observations of Venus near maximum western elongation These October 2013 Proposal (PI: Clarke) STIS MAMA observations are near maximum eastern elongation

FRR: Venus Proposal P. 25October 16, FSW, S/C H/W Changes and Implementation 3.1FSW 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 (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

FRR: Venus Proposal P. 26October 16, FSW, S/C H/W Changes and Implementation 3.1FSW 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 (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

FRR: Venus Proposal P. 27October 16, FSW, S/C H/W Changes and Implementation 3.2FSW Software Structure/Resource Changes None. 3.3CPM2 & 3 Update Recommendation N/A 3.4Supporting Ground System Changes None. 3.5Supporting Documentation Changes None. 3.6Release Messages SSM232 IP-248_Venus_Observation_Macros.docx PNM_ TXT

FRR: Venus Proposal P. 28October 16, Testing and Verification 4.1Unit 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 4.2System 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 / PRD D07756S PCSSIM 54A On-Orbit patches installed Gyro »Installation Procedure Verification using VSSNOR and IP-248 Completed in 486 Lab

FRR: Venus Proposal P. 29October 16, Engineering Test / Installation 4.3FSW/Operations Acceptance Testing, TSAR Status and Results VEST Configuration for October 3, 2013 (Day 276): »Ground system software – CCS Version »CCS string – H Test »Database – PRD-O07700ST Quick update of QFSW37ARAM2.tcl proc applied »NSSC-1/CDH2 FSW »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

FRR: Venus Proposal P. 30October 16, Engineering Test / Installation 4.3FSW/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

FRR: Venus Proposal P. 31October 16, Engineering Test / Installation 4.3FSW/Operations Acceptance Testing, TSAR Status and Results (Cont’d) HSTAR and TSAR Status TSARTitle & DescriptionAssigneeResolutionStatus 4146Response team could not access STScI test machines for PNM transfer – Password had been changed CCSThe OAT products were manually transferred. CCS is obtaining a new account from the STScI. In Analysis 4147Plot Freeze within FGS Pickles Display – FGS pickles displays on both VOCC and H-String froze before return to FGS default CCSResolved to CR Workaround: Close/reopen Pickles display between guide star acqs. Use of this display is not critical to the activity. Resolved 4148STK/CCS on PCS STK workstation, OSRS03 not working – Symantec blocked CCS from coming up due to JAVA versions NetworkThe workstation was tested following the OAT with no problems. Use of STK is not critical to the activity. Open HSTARTitle & DescriptionAssigneeResolutionStatus 13826Multiple Data Dropouts on H-string FEP – H-string VLANs 218 and 228 were being scanned System Admin Resolved during the OAT by recycling the H-string Open

FRR: Venus Proposal P. 32October 16, Engineering Test / Installation 4.3FSW/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

FRR: Venus Proposal P. 33October 16, Testing and Verification 4.4H/W Interfaces Impact & Verification Matrix HST486 FSW 4.5Testing 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 – “OTA Light Shield Baffle Thermal Limits” ( dated September 17, 2013) DCR’sFVS TESTS486LAB and/or DSTIF TESTS RESULTS –VENOBS1 VENOBS2 VSSNOR/IP-248All Passed

FRR: Venus Proposal P. 34October 16, Engineering Test / Installation 4.6Differences 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

FRR: Venus Proposal P. 35October 16, Operations Activities/ Installation 5.1Overview 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 5.2Ops 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)

FRR: Venus Proposal P. 36October 16, Operations Activities/ Installation 5.3Summary 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

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

FRR: Venus Proposal P. 38October 16, Operations Activities/ Installation 1 st op. to load, dump and compare SPC macro & Activate Macro 1 2 nd Opportunity GS Pair Venus +7d

FRR: Venus Proposal P. 39October 16, Operations Activities/ Installation 1 st slew inside of the 50d SAZ 3 rd Opportunity Single GS Venus GS Pair Venus +7d

FRR: Venus Proposal P. 40October 16, Operations Activities/ Installation Single GS Venus GS Pair Venus +7d

FRR: Venus Proposal P. 41October 16, Operations Activities/ Installation Single GS Venus GS Pair Venus +7d

FRR: Venus Proposal P. 42October 16, Operations Activities/ Installation Single GS Venus GS Pair Venus +7

FRR: Venus Proposal P. 43October 16, Operations Activities/ Installation 1 st op. to activate Post-Venus Observation macro 2 2 nd Opportunity

FRR: Venus Proposal P. 44October 16, Operations Activities/ Installation 3 rd Opportunity

FRR: Venus Proposal P. 45October 16, Monitoring and System Impacts 6.1On-Orbit Validation / Monitoring DMS and FSW will validate the successful load of the macros DMS will verify macro execution 6.2System 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 – “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

FRR: Venus Proposal P. 46October 16, Monitoring and System Impacts 6.3Supporting Operation Changes None. 6.4Supporting PRD Changes None. 6.5Supporting STScI Changes None. 6.6Subsystem Training Module Changes None.

FRR: Venus Proposal P. 47October 16, Constraints and Restrictions Review 7.1CARD 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 – “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 – “OTA Light Shield Baffle Thermal Limits” ( 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 – “STIS MAMA Global Bright Object Limits” and – “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 7.2OLD No operations limitations are violated and no waivers are required

FRR: Venus Proposal P. 48October 16, Contingency Planning 8.1Vehicle 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

FRR: Venus Proposal P. 49October 16, Contingency Planning 8.1Vehicle 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 – “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 – “CONTINGENCY: Commanding SWSP during Venus Observation”) MAT LEI has been suspended throughout the Venus visit period

FRR: Venus Proposal P. 50October 16, Contingency Planning 8.1Vehicle 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 ( 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

FRR: Venus Proposal P. 51October 16, Contingency Planning 8.1Vehicle Contingencies (Cont’d) HST in the Sun (Cont’d) »Vital Statistics – Prior Venus Observations Observation Science Exposure Time Angle to Sun Limb (degrees) Sunlit Time inside SAZ While Slewing Away from Venus Guide Star January s per orbit 46.32m 20s January s46.02m 30s Dec 28, 2010 orbit 1153s46.22m 14sS in FGS1 on centerline Dec 28, 2010 orbit 2153s46.23m 1sS in FGS1 ~50” from centerline Jan 22, 2011 orbit 158s46.11m 57sS8OF in FGS1 12” from centerline Jan 22, 2011 orbit 258s46.11m 50sS8OF in FGS1 on centerline Jan 27, 2011 orbit 1120s45.73m 12sS8L in FGS1 36” from centerline Jan 27, 2011 orbit 2120s45.73m 2sS8LA in FGS2 29” from centerline

FRR: Venus Proposal P. 52October 16, Contingency Planning 8.1Vehicle Contingencies (Cont’d) HST in the Sun (Cont’d) »Vital Statistics – October 24, 2013 »Total time pointed in SAZ (sunlit & shadow) is minutes per orbit. Observation Science Exposure Time Angle to Sun Limb (degrees) Sunlit Time inside SAZ While Slewing Toward Venus Guide Star Visit 015m (i.e., 300s)46.60m 14sS8G in FGS1 <= ~70” from centerline Visit 025m46.60m 36sS8G in FGS1 <= ~60” from centerline Visit 045m46.60m 28sS8G in FGS1 <= ~45” from centerline Visit 055m46.60m 55sS8G in FGS1 <= ~60” from centerline

FRR: Venus Proposal P. 53October 16, Contingency Planning 8.1Vehicle Contingencies (Cont’d) FGS exposure to Venus »Concern The FGS photo-multiplier tubes may be exposed to bright light if large attitude errors (>300 arcsec) allow the FGS to see Venus »Precautions The guide stars for the single star acquisitions are angularly separated as far as possible from Venus and are in FGS1 (farthest from STIS) –Bad OBADs will be very unlikely to put Venus within the FGS’s guide star search radius –S8G – ~870”, ~927”, and ~1046” from Venus on Orbits 2, 3, and 4, respectively –S8G – ~956” from Venus on Orbit 6 The guide stars for the single star acquisitions have been used on orbit »Analysis Goodrich assessed potential PMT damage for a worst-case event resulting in an attempted acquisition of Venus (ref: Goodrich Memo A16-ST-2254) –The immediate effect of the attempted Venus acquisition would be the temporary incapacitation of the PMTs due to dark count elevation from several to up to 48 hours –The long term effect of the attempted Venus acquisition could be a decrease in reliability from 1-3% depending on how long Venus resides in the FGS’s FOV

FRR: Venus Proposal P. 54October 16, Contingency Planning 8.1Vehicle Contingencies (Cont’d) 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 7 degree slew to Venus Perform guide star acquisition test before the Venus observing timeframe –Tests occurred on September 17 and September 18 –Both were successful 8.2Ground Contingencies Loss of communication with HST »Continue procedure at next opportunity Loss of primary CCS string during activity »Switch to backup string and resume activity

FRR: Venus Proposal P. 55October 16, Engineering Support Requirements 9.1Personnel Test Conductor – J. Regalado in MOR/OSR NASA OM – M. Myslinski 486 FSW, PCS, and Sys Mgmt – N. Roy, J. Germany, M. Slater in OSR EPS, I&C, OTA, P/L FSW, Safing, SI, and TCS – on-call FOT – J. Edwards/D. Grimes (am.) & D. Schaible/T. Walsh (pm.) in MOR 9.2Communications / Data Circuit assignments: »R/T OPS COORD – Primary circuit for Test Conductor and Shift Supervisor SMS – OTA signoff is required Operations Requests (OR’s): » – “Venus Observation” » – “CONTINGENCY: Commanding SWSP during Venus Observation” Flash Reports will be issued following: »Macro loads »Macro 1 execution »Macro 2 execution FRR material is available on EDOCS web site

FRR: Venus Proposal P. 56October 16, Engineering Support Requirements 9.3CCS Configuration CCS Strings »Prime Ops on F-String – CCS »Back-up Ops on D- and H-Strings – CCS OPS PRD O07700S 486 FSW loads transferred in accordance with AD 2-04

FRR: Venus Proposal P. 57October 16, Liens/Forward Plan Liens None Forward Plan N/A

FRR: Venus Proposal P. 58October 16, 2013 Backup Material

FRR: Venus Proposal P. 59October 16, 2013 Backup Material TCS Analysis for October 2013 Venus Observation From: Lewis, Deneen Sent: Tuesday, September 17, :54 PM To: Haskins, David N; Myslinski, Mike; Lupie, Olivia L. Cc: Smith, Daniel C.; Dunham, Larry; Slater, Mark A.; Crabb, Bill; Waldo, Greg; Krol, Stan; Setty, Amar O; Wenz, Mike Subject: TCS Analysis for October 2013 Venus Observation All, For the TCS analysis for planned October 2013 Venus Observation, EM: MOSES 1067 (Light Shield Thermal Analysis for Venus Observations) was reviewed. This EM addresses the concern of a direct solar load striking the HST light shield internal baffles, located inside the aperture, resulting in temperatures approaching 300 degF. Black paint on the baffles is prone to outgassing when temperatures exceed 250 degF resulting in potential contamination of the primary and secondary mirrors. Further studies performed in 2004 concluded that the outgassing range could be extended to 300 degF. The data and observations from the EM MOSES 1067 analysis and the study in 2004 were compared to the upcoming October 2013 Venus observation to confirm compliance with CARDs and This comparison will serve as the basis for the TCS analysis as there is no HST thermal flight telemetry (baffle temperature monitors) in the area of the direct solar load. Analysis documented in EM: MOSES 1067 indicate that the peak baffle temperature reached 220 degF with HST configured in the Venus Observation attitude (46.3 degrees from the +V1 axis sun angle) over a single orbit and the sun illuminating inside the aperture for seven minutes. After 15 minutes the temperatures exceeded 250 degF.

FRR: Venus Proposal P. 60October 16, 2013 Backup Material TCS Analysis for October 2013 Venus Observation (Cont’d) Additional analysis with a configuration similar to the proposed October 2013 Venus Observation showed that the peak baffle temperature reached 171 degF with HST configured in the Venus Observation attitude for three consecutive orbits and the sun illuminating inside the aperture for two minutes each orbit (reference plot from EM MOSES 1067 below). Again, after 15 minutes the temperatures exceeded 250 degF. Both analyses conclude that pointing inside the aperture while HST is in sunlight can be tolerated for at least 15 minutes without the temperature of the black paint on the baffles causing contamination issues. (Baffles)

FRR: Venus Proposal P. 61October 16, 2013 Backup Material TCS Analysis for October 2013 Venus Observation (Cont’d) (Shroud)

FRR: Venus Proposal P. 62October 16, 2013 Backup Material TCS Analysis for October 2013 Venus Observation (Cont’d) The October 2013 Venus Observation proposal consists of visits scheduled over six consecutive orbits with HST configured with the sun pointed 46.6 degrees from the +V1 axis and the sun illuminating inside the aperture for a maximum of 1 minute 35 seconds. Note, HST’s maximum previous exposure to sunlight was 3 minutes 12 seconds (January 27, 2011). Although, CARD (HST Sun Pointing Limits) will require a waiver since HST line-of-sight will be pointed closer than 50 degrees to the sun, per the EM MOSES 1067 data CARD (OTA Light Shield Baffle Thermal Limits) is satisfied as the baffle temperatures will not exceed 250 degF with sunlight exposure much shorter than 15 minutes. CARD protects for light shield baffle temperatures exceeding 300 degF. Also, the solar intensity is lower in October than the December-January timeframe resulting in cooler temperatures overall. With a similar configuration as the EM analysis coupled with shorter sun exposure durations and lower sun intensity, TCS SE confirms the configuration can be tolerated as it poses no threat of contamination. Deneen Lewis Electrical Power Systems Engineer Jackson & Tull Engineers, Hubble Space Telescope Program Goddard Space Flight Center