frr: venus proposal 13047 p. 1october 16, 2013 flight readiness review (frr): venus proposal 13047...

FRR: Venus Proposal 13047

P. 1October 16, 2013

Flight Readiness Review (FRR):

Venus Proposal 13047

October 16, 2013



Agenda

1.0 Engineering Team (M. Slater)

2.0 Introduction/Overview (M. Slater, T. Roman,C. Proffitt)

2.1 Objective2.2 Statement of Adherence to AD 2-16 & AD 2-172.3 Background2.4 On-Orbit History

3.0 FSW, S/C H/W Changes and Implementation

(N. Roy)

3.1 FSW and/or S/C H/W Functional Changes3.2 FSW Software Structure/Resource Changes3.3 CPM2 & 3 Update Recommendation3.4 Supporting Ground System Changes3.5 Supporting Documentation Changes 3.6 Release Messages

4.0 Testing and Verification (N. Roy, J. Regalado)4.1 Unit and Build Level Testing/Results4.2 System Level Testing/Results4.3 FSW/Operations Acceptance Testing, TSAR Status

and Results4.5 H/W Interfaces Impact & Verification Matrix4.4 Testing Liens and Limitations4.6 Differences between Flight and Test Configurations

5.0 Operations Activities/Installation (J. Regalado, M. Reinhart)

5.1 Overview and Initial Conditions5.2 Ops Request and Script Review5.3 Summary of SMS Observing Plans5.4 Timeline Review – MEGG

6.0 Monitoring and System Impacts (M. Slater)6.1 On-orbit Validation / Monitoring6.2 System Impacts6.3 Supporting Operations Changes6.4 Supporting PRD Changes6.5 Supporting STScI Changes6.6 Subsystem Training Module Changes

7.0 Constraints and Restrictions Review

(M. Slater)

7.1 CARD7.2 OLD

8.0 Contingency Planning (M. Slater)8.1 Vehicle Contingencies8.2 Ground Contingencies

9.0 Engineering Support Requirements

(M. Slater)

9.1 Personnel9.2 Communications / Data9.3 CCS Configuration

10.0 Liens/Forward Plan (M. Slater)



HST486 FSW

S. BenedictS. DuhaneyN. RoyRon StattelB. Vreeland

Payload FSW

D. EhlersC. HoffmanM. KellyB. SerranoC. Townsley

STScI C. ProffittM. ReinhartT. Roman

HITT J. AtwellS. Bozievich

VOCC B. SmithJ. Smith

Sys Mgmt

M. Slater

FOT J. EdwardsD. GrimesB. PatelD. SchaibleT. Walsh

DMS/I&C

J. RegaladoS. Sands

EPS/TCS

D. Lewis

OTA J. StockM. Wenz

PCS/SAC

E. KimmerD. Murphy

Safing E. Moy

SI S. ArslanianE. GrahamS. Swain

1.0 Engineering Team



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”

http://www.stsci.edu/cgi-bin/get-proposal-info?id=13047&observatory=HST






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




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




2.3 Background (Cont’d)• Observing Strategy Details

» Visits currently scheduled on October 24, 2013» Scheduled in 6 consecutive orbits» Order

1. Visit 03 – sky background2. Visit 01 – Venus3. Visit 02 – Venus4. Visit 05 – Venus5. Visit 06 – sky background6. Visit 04 – Venus




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

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°




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

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°


P. 10October 16, 2013


2.3 Background (Cont’d)• Venus Observation CAD Models/Geometries

» STIS 52x0.5 Slit on Venus in Visit 01


P. 11October 16, 2013


2.3 Background (Cont’d)• Venus Observation CAD Models/Geometries (Cont’d)

» HST’s View of Venus (t=0)


P. 12October 16, 2013



» HST’s View of Venus (t=0) (Cont’d)• Bodies that are relevant to this observing program

Venus+7D VenusSun


P. 13October 16, 2013



» HST’s View of Venus (t=0) (Cont’d)• Other bodies that happen to be appear in this view

Pluto Mercury

Saturn & moons


P. 14October 16, 2013



» HST’s View of Venus (t=0) (Cont’d)• At about this time, HST is beginning its slew from Venus+7D to Venus


P. 15October 16, 2013



» HST’s View of Venus (t=5m)• Slew to Venus is continuing. Sun is about to set.

Earth

terminator


P. 16October 16, 2013



» HST’s View of Venus (t=10m)• Sun has set. Slew to Venus is complete. GS Acq. is in progress.


P. 17October 16, 2013



» HST’s View of Venus (t=15m)• Science observation is beginning


P. 18October 16, 2013



» HST’s View of Venus (t=20m)• Science observation is continuing


P. 19October 16, 2013



» HST’s View of Venus (t=25m)• Science observation is complete. Slew away from Venus is in progress.


P. 20October 16, 2013



» HST’s View of Venus (t=30m)• Slew away from Venus is complete. Pointing at Venus+7D with gyro

guiding.


P. 21October 16, 2013


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


P. 22October 16, 2013


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


P. 23October 16, 2013


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


P. 24October 16, 2013


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


P. 25October 16, 2013


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


P. 26October 16, 2013


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


P. 27October 16, 2013


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


P. 28October 16, 2013

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


P. 29October 16, 2013

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


P. 30October 16, 2013


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


P. 31October 16, 2013


4.3 FSW/Operations Acceptance Testing, TSAR Status and Results (Cont’d)• HSTAR and TSAR Status

TSAR Title & Description Assignee Resolution Status

4146 Response team could not access STScI test machines for PNM transfer – Password had been changed

CCS The OAT products were manually transferred. CCS is obtaining a new account from the STScI.

In Analysis

4147 Plot Freeze within FGS Pickles Display – FGS pickles displays on both VOCC and H-String froze before return to FGS default

CCS Resolved to CR 10256. Workaround: Close/reopen Pickles display between guide star acqs. Use of this display is not critical to the activity.

Resolved

4148 STK/CCS on PCS STK workstation, OSRS03 not working – Symantec blocked CCS from coming up due to JAVA versions

Network The workstation was tested following the OAT with no problems. Use of STK is not critical to the activity.

Open

HSTAR Title & Description Assignee Resolution Status

13826 Multiple 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


P. 32October 16, 2013


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 testThe 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


P. 33October 16, 2013

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)

DCR’s FVS TESTS 486LAB and/or DSTIF TESTS

RESULTS

1637 2 –VENOBS1

VENOBS2

VSSNOR/IP-248 All Passed


P. 34October 16, 2013


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


P. 35October 16, 2013

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)


P. 36October 16, 2013


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 06 – sky background• 297/17:30:48 – Pair: No Changes


» 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


P. 37October 16, 2013


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


P. 38October 16, 2013


1st op. to load, dump and compare SPC macro &Activate Macro 1

2nd Opportunity

GS Pair Acq @ Venus +7d


P. 39October 16, 2013


1st slew inside of the 50d SAZ

3rd Opportunity

Single GS Acq @ VenusGS Pair Acq @ Venus +7d


P. 40October 16, 2013


Single GS Acq @ Venus




P. 41October 16, 2013


Single GS Acq @ Venus GS Pair Acq @ Venus +7d


P. 42October 16, 2013


Single GS Acq @ VenusGS Pair Acq @ Venus +7


P. 43October 16, 2013


1st op. to activate Post-Venus Observation macro 2

2nd Opportunity


P. 44October 16, 2013


3rd Opportunity


P. 45October 16, 2013

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


P. 46October 16, 2013

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.


P. 47October 16, 2013

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


P. 48October 16, 2013

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


P. 49October 16, 2013


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


P. 50October 16, 2013


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


P. 51October 16, 2013


8.1 Vehicle 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 1995 22-109s per orbit

46.3 2m 20s

January 2003 255s 46.0 2m 30s

Dec 28, 2010 orbit 1 153s 46.2 2m 14s S924000129 in FGS1on centerline

Dec 28, 2010 orbit 2 153s 46.2 3m 1s S924000129 in FGS1~50” from centerline

Jan 22, 2011 orbit 1 58s 46.1 1m 57s S8OF000650 in FGS112” from centerline

Jan 22, 2011 orbit 2 58s 46.1 1m 50s S8OF000650 in FGS1on centerline

Jan 27, 2011 orbit 1 120s 45.7 3m 12s S8L2000017 in FGS1 36” from centerline

Jan 27, 2011 orbit 2 120s 45.7 3m 2s S8LA045471 in FGS2 29” from centerline


P. 52October 16, 2013


8.1 Vehicle Contingencies (Cont’d)• HST in the Sun (Cont’d)

» Vital Statistics – October 24, 2013

» Total time pointed in SAZ (sunlit & shadow) is 20-21 minutes per orbit.

Observation

Science Exposure

Time

Angle to Sun Limb (degrees)

Sunlit Time inside SAZ While Slewing Toward

Venus Guide Star

Visit 01 5m (i.e., 300s) 46.6 0m 14s S8G1000134 in FGS1<= ~70” from centerline

Visit 02 5m 46.6 0m 36s S8G1000134 in FGS1<= ~60” from centerline




P. 53October 16, 2013


8.1 Vehicle 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

– S8G1000134 – ~870”, ~927”, and ~1046” from Venus on Orbits 2, 3, and 4, respectively

– S8G1000147 – ~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


P. 54October 16, 2013


8.1 Vehicle 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

8.2 Ground 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


P. 55October 16, 2013


9.1 Personnel• 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

9.2 Communications / Data• Circuit assignments:

» R/T OPS COORD – Primary circuit for Test Conductor and Shift Supervisor

• SMS – OTA signoff is required

• Operations Requests (OR’s):» 19500-0 – “Venus Observation”» 19497-2 – “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


P. 56October 16, 2013


9.3 CCS Configuration• CCS Strings

» Prime Ops on F-String – CCS 8.4.0.0.12» Back-up Ops on D- and H-Strings – CCS 8.4.0.0.12

• OPS PRD O07700S• 486 FSW loads transferred in accordance with AD 2-04


P. 57October 16, 2013

10.0 Liens/Forward Plan

Liens• None

Forward Plan• N/A


P. 58October 16, 2013

Backup Material


P. 59October 16, 2013

Backup Material

TCS Analysis for October 2013 Venus Observation

From: Lewis, DeneenSent: Tuesday, September 17, 2013 3:54 PMTo: 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, MikeSubject: 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 2.2.1.7 and 3.1.7.3. 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.


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)


P. 61October 16, 2013

Backup Material


(Shroud)


P. 62October 16, 2013

Backup Material


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 3.1.7.3 (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 2.2.1.7 (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 2.2.1.7 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 LewisElectrical Power Systems EngineerJackson & Tull Engineers, Hubble Space Telescope ProgramGoddard Space Flight Center301-286-3481

frr: venus proposal 13047 p. 1october 16, 2013 flight readiness review (frr): venus proposal 13047...

Documents

venus proposal

venus observations

venus special

venus pi

slater slide

supporting operations

supporting stsci changes

supporting prd changes