STARDUST Project CRITICAL EVENTS READINESS REVIEW COMET P/WILD 2 ENCOUNTER NAVIGATION

20 Nov 2003 K. E. Williams - CERR1 of 7

STARDUST

STARDUST ProjectSTARDUST Project CRITICAL EVENTS READINESS REVIEW

COMET P/WILD 2 ENCOUNTER

NAVIGATION

Kenneth E. Williams

JPL: 303-411 AM / 301-427 PMLMA: MSA

+1 818 354-127508:00 AM - 05:00 PM PST

20 Nov 2003


STARDUST

Navigation Requirements

• None specified, expected Navigation performance and capability adopted as requirement

– Must deliver S/C to 300 km flyby within 16 km (1-sigma) in B.T and B.R after last TCM (nominally at E-18h)

– Must know (but not control) Time of Encounter to 1,100 km or 180 sec (1-sigma) at E-8h

– This level of accuracy provides for:

• Collecting 500 particles 15 m or larger

• Gives a probability of serious impact to the spacecraft shielding 60 times less than Giotto at Halley Encounter or less than 2 %

• Enables the spacecraft to maintain carrier signal during Wild 2 Flyby


STARDUST

Robust Wild 2 Encounter Navigation Design

• Maneuver startegy flexible to accommodate uncertainty in time of comet detection

• Success of Wild 2 Encounter and ease of operations dependent on two major factors:

– Optical Nav must detect Wild 2 before E-8d (DONE!)

• Expected to be seen by E-20d (already detected as of E-45d)

– At least two TCM’s must be performed during Approach

• One at E-10d (nominal), E-6d or E-2d (contingencies)

• Another at E-2d (nominal) or as late as E-18h or E-12h

• Option to do early TCM at E-30d if comet already detected

– Opportunity to correct Wild 2 ephemeris error early

– Not critical - ~80 m/s margin available to ensure 100 psia for ACS response during Encounter (another ~100 m/s in reserve thru EOM)

• Nav had implemented all timelines and interfaces during the Annefrank Encounter real-time operations and has retested for recent ORT


STARDUST

Maneuver Design

• Maneuvers prior to E-2d to target to 150 km

– First TCM opportunity at E-30d (preliminary Delta-V ~1.5 m/s)

– Next TCM at E-10d (< 7 m/s in worst case, 275 km 1-sigma delivery error)

• Time-of-flight does not need to be controlled

– ~180 sec (1-sigma) worst case if uncorrected (Delta-V <3 m/s)

• Can slip as late as E-6d (<5.4 m/s with no TOF correction)

• Maneuver at E-2d to shift to final target at 300 km

– 70% probability within 90° roll about approach velocity vector

• Project desire to avoid > 90° turn away from Sun/Earth if possible

– Requires < 4 m/s to improve to <65 km, 1-sigma, delivery error)

– Time-of-flight not controlled (8-hr development timeline)


STARDUST

Maneuver Design - Continued

• Maneuver may be performed at E-18h to clean up execution errors from E-2d TCM to improve targeting precision

– Will be performed only if statistically meaningful

• 28% probability not needed at all

• 22% probability beyond 90° roll about approach velocity vector

– Time-of-flight not controlled (8-hr development timeline)

– Can be slipped to as late as E-12h (< 2.3 m/s Delta-V and <24 km, 1-sigma, delivery error --> 13.5° bank angle at CA --> still supports MGA carrier only)

• GO/No-GO criteria in place for all Wild 2 approach maneuvers (tested at Annefrank and to be retested in upcoming ORT)

• Near-continuous DSN coverage in place with dual coverage within E±2h


STARDUST

Maneuver Design - Contingencies

• TCM at E-30d can be cancelled

• TCM at E-10d can be slipped to E-6d or E-2d

• TCM at E-2d can be slipped to as late as E-12h

• As final option, up to 5 TCM’s pre-designed and tested to move away from comet in Earth-Wild 2 plane at E-6h

– Will be uplinked and stored on S/C before E-2d

– No attitude turns needed

– Designed to cover range of 100-1000 km of movement in B-plane at E-6h

– If desired, can be executed anytime after E-2d if desired to further augment movement away from Wild 2

• In the event of camera failure, flyby will be targeted to safe distance (>1,000 km) based on latest Wild 2 ephemeris knowledge

– Implemented by 1 of 5 stored TCM’s if desired as late as E-6h

– Nav stands down for the remainder of the Encounter period


STARDUST

Navigation Readiness Status

• All operations, timelines and interfaces tested successfully at previous Annefrank Flyby– Annefrank too dim on Approach - Opt Nav performed with Flyby Annefrank/star

images• New ORTs have/will retest for last 2.5 days prior to Wild 2 Encounter

– Participants to be certified for operations by Project/MMO • Doppler and Ranging Only, no-Delta DOR implemented• No new observations, facilities, first-time events for Radio Nav and Maneuver• Workforce, Backups and Contingencies in place• Navigation Advisory Group (NAG) Readiness Review successfully completed

– 9 RFA’s considered• Reduced number and complexity of approach maneuvers where feasible and

adjusted staffing plans to reduce fatigue, meet CAN rqmts• Possible Opt Nav staffing at LMA still an open issue• All will be reconciled before Dec 15

– Agreed that Nav ready and qualified, pending final ORT, for Wild Encounter Operations


STARDUST

Backup Charts

BU-1


STARDUST

Navigation Staffing Plan

BU-2

DATE/TIME (PST)

30-Dec 12:00 30-Dec 18:00 31-Dec 00:00 31-Dec 06:00 31-Dec 12:00 31-Dec 18:00 01-Jan 00:00 01-Jan 06:00 01-Jan 12:00 01-Jan 18:00 02-Jan 00:00 02-Jan 06:00 02-Jan 12:00

Hours from Encounter72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 +1+2+3+4+5

EVENT < Begin Hourly Images… < TCM-12 Design > < TCM-12/Prelim Nuc Trk > <-TCM-13 Design-><TCM-13> <TCM-14 select/Fin Nuc Trk> <W2 Enc>

Meetings/Reviews P C Q P C P C C Q G C P C(P =Peer Rvw; C = Cmd Conf, Q = Quicklook Assess)

OPNAVNick Mastrodemos*Ed Riedel*Shyam Bhaskaran

RADIO/ODEric Carranza*Brian Kennedy*Tung-Han You

MNVRRam Bhat*Cliff Helfrich*Ken Williams*

RMDC/MMNAV†

Nav Sys AdminScott FullnerDimtrios Gerasimatos

DMA**Boris SemenovChuck Acton

GDS†**

DATE/TIME (UTC)

30-Dec 19:0031-Dec 00:00 31-Dec 06:00 31-Dec 12:00 31-Dec 18:00 01-Jan 00:00 01-Jan 06:00 01-Jan 12:00 01-Jan 18:00 02-Jan 00:00 02-Jan 06:00 02-Jan 12:00 02-Jan 18:00 03-Jan 00:00

NOTE: All of above considered on call when not at JPL.* Will follow late evening schedule for at least two days prior to this period.† Individuals to be assigned by separate team chiefs (on SDU emergency contact list).** Periods shown can be on-call but require being on high alert and no more than 1/2 hour from JPL.


STARDUST

Some Feedback from Navigation Peer ReviewSome Feedback from Navigation Peer Review

• Simplify Maneuver Plan √– TOF control not required (adjust encounter seq start time; allow schedule

for final two days to float ±1 hour, provided known by Dec 30)– Test of compressed (2.5 day) full TCM design entails schedule risk - not

needed (rely on existing 8-hour and 10-day TCM design templates)– Clarify requirements/rationale for avoiding off-sun rolls for later TCMs

• Adjust Staffing Plan √– Additional OD support recommended to avoid fatigue while still meeting

CAN requirements– Reduced MMNAV support (critical activities only)– Wider participation in meetings involving key decisions (include in ORT)

• Recommend backup OPNAV support at LMA in case JPL goes down (as additional measure to support selection of 1 of 5 “canned” maneuvers)

• Dual DSN coverage desirable for TCMs (probably not feasible given contention for DSN resources)

BU-3


STARDUST

Nav Personnel Training and CertificationNav Personnel Training and Certification

• Thread Tests

– Starting condition prior to first TCM (TCM-10 on 12/3/03)

– Exercise interfaces among Nav subteams (OPNAV, Radio/OD, Maneuver; include Solar System Dynamics for second test)

– Repeat interactions through subsequent TCMs up to Wild 2 Encounter

• ORTs

– Annefrank Encounter ORT (10/31/02)

– TCM-12 and Preliminary Nucleus Tracking Update (Completed 11/5/03)

– TCM-13, TCM-14 Contingency and Final Nucleus Tracking Update (Planned for 12/9-10)

• Participation by all Nav personnel in recent activities provides for operational certification (endorsed by Stardust Project Mgr and MMO GNC Team Chief)

BU-4


STARDUST

Navigation External InterfacesNavigation External Interfaces

SCTNAVRMDCDSNSDU (S/C)Cmd, Seq, Cfg Files, CarrierTlm, CarrierTRK-2 -34TlmCmd, Seq, Cfg FilesRanging, DopplerDOMMPF,SPK,OPNAVCfg Files

MPDF, MIF, Cfg Filesand Reconstructed SFFDMATlmImage,SFF updatesVoice(Telecon Line 4-1275; MarsCoord,MarsNet)

TOF

BU-5


STARDUST

Navigation Internal InterfacesNavigation Internal Interfaces

OPNAVRAD/ODMNVRImage (from dusty)MPDF, MIF, Cfg Files (from DOM)SSDPSF, Optical Partials NamelistObservation

FileW2 Eph,DE 405PV-File*MPF, SPK (to DOM)MVF,P-FileNAVTRK-2-34 (with stoic2000, gimcals, tropcals) and SFF Updates(via oscarx and dusty)

OD Solution(with all updated Ephem as needed)

Radio-Only P-File* Recent radio-only or previous mergedOPNAV Cfg Files (to DOM)

TOF (FAXed release form)Reconstructed SFF (from DOM)

BU-6


STARDUST

Communications for 300 km FlybyCommunications for 300 km Flyby

BU-7


STARDUST

Selected Maneuver Analysis ResultsSelected Maneuver Analysis Results

BU-8

First TCM at E-30d (Full Design)Maneuver Epoch

(UTC)Mean (m/s)

95%tile (m/s)

Bmax (km, 1 )s

LTF Ctrl † ( , sec 1 )s

-30E d 3- -03Dec 1.54 2.58 706 189-10E d 23- -03Dec 1.75 3.42 270 113-2 ( - )E d roll only 31- -03Dec 1.98 3.88 65 113-18 ( - )E h roll only 2- -04Jan 0.78 1.56 16 113

--> 2TOTAL W 6.05 8.91 16 113

-10 ( )First TCM at E d Full DesignManeuver Epoch

( )UTC Mean

( / )m s95% tile( / )m s

( , Bmax km1 )s

LTF Ctrl † ( , sec 1 )s

-10E d 23- -03Dec 4.45 6.87 275 114-2 ( - )E d roll only 31- -03Dec 2.00 3.92 65 114-18 ( - )E h roll only 2- -04Jan 0.78 1.57 16 114

--> 2TOTAL W 7.23 10.52 16 114

-10 ( )First TCM at E d No LTF CorrectionManeuver Epoch

( )UTC Mean

( / )m s95% tile( / )m s

( , Bmax km1 )s

LTF Ctrl( , sec 1 )s *

-10 ( - )E d roll only 23- -03Dec 2.06 3.28 264 185-2 ( - )E d roll only 31- -03Dec 1.71 3.29 65 185-18 ( - )E h roll only 2- -04Jan 0.79 1.58 16 185

--> 2TOTAL W 4.55 6.83 16 185

-6 ( )First TCM at E d No LTF CorrectionManeuver Epoch

( )UTC Mean

( / )m s95% tile( / )m s

( , Bmax km1 )s

LTF Ctrl( , sec 1 )s *

-6 ( - )E d roll only 27- -03Dec 3.41 5.40 158 185-2 ( - )E d roll only 31- -03Dec 1.37 2.52 65 185-18 ( - )E h roll only 2- -04Jan 0.78 1.59 16 185

--> 2TOTAL W 5.56 8.07 16 185* , Dominated by comet ephemeris error without LTF correction† ( )Impact of TOF correction limited by OD error


STARDUST

Final TCM GO/No-GO and Selection CriteriaFinal TCM GO/No-GO and Selection Criteria

E-2d (150 --> 300 km) and E-18h TCM

BU-9

E-6h TCM (Contingency)

E-18h Target Selection

+++300 km 350 km To Wild 2Target to point“above” Wild 2(< 90 deg Roll)

Target to point“above” Wild 2(90-180 deg Roll)

Remove out-of-plane error only(~90 deg Roll)*

GONo-GO++3sd ” Minimum safe distance” 2above Wild

( ):Decision Criterion if GO 1 5 “ ” ’Pick smallest of canned TCM s . which shifts location out by at least d

/To Earth Sun 2To WildTarget Point (“above” Wild 2)+*GO*No-GO+1sProjected Location and

Uncertainty in-B Plane


STARDUST

Contingency Maneuver (E-6 Hours) forContingency Maneuver (E-6 Hours) forOperational BackupOperational Backup

B-Plane shift desired(OD uncert. + 300 km)

10 244 544 600 km9 223 523 600 km8 202 502 500 km7 181 481 500 km6 160 460 500 km5 139 439 500 km4 118 418 500 km3 97 397 400 km2 77 377 400 km1 56 356 400 km

Last JPL contact

(days from encounter)

OD uncertainty (1-sigma,

RSS)

Maneuver to be executed at E–6 hours

(in terms of tgt movement)

• Can be used at E-6 hours to deal with last-minute anomaly or earlier (e.g., E-2d) if JPL disabled (e.g., earthquake)• Maneuver identified according to aimpoint shift expected at E-6 hours (effect would be 8 times greater at E-2d)• Select according to last JPL contact by default• If Op Nav support available at LMA, select according to estimate of OD uncert.• 100 and 1000 km shifts also recommended to round out set of 5 “canned” TCMs

BU-10

Documents

STARDUST Project CRITICAL EVENTS READINESS REVIEW COMET P/WILD 2 ENCOUNTER NAVIGATION