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STARDUST

STARDUST ProjectSTARDUST Project CRITICAL EVENTS READINESS REVIEW

COMET P/WILD 2 ENCOUNTER

OPTICAL NAVIGATION

N. Mastrodemos

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

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

20 Nov 2003

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STARDUST

Optical Navigation Requirements

• Need to detect 8th visual magnitude stars at signal-to-noise 7 or higher both outside and through-periscope to support approach OpNav.

– Most recent images outside periscope confirm that

• Need to model camera geometric parameters to < 0.2 pixels

– Latest images yield results at 0.2 pixel level

• Need to Detect Wild 2 > E-8d for Ease of Operations

– Wild2 already detected as of Nov 17

• This level of performance will provide 16 km (1-) flyby control accuracy at E-18h to insure dust collection, spacecraft safety and carrier signal during flyby

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STARDUST

Wild 2Wild 2

• Windowed frame • Wild 2 in a 15 sec exposure

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STARDUST

Observation Plan

• Most OpNav image set consists of 25 windowed frames with exposures in the 3 - 20 second range.

• E-50 to E-30d: Two image sets per week

• E-30d to E-10d: One image set per day

• E-10d to E-3d: 3 image sets per day

• E-3d to E-12h: 1 image set/hour (up to 16 frames per set)

• Windowed images used for calibration and at Annefrank approach

– Already imaged Wild2 with windowed images

• OpNav tools and people performed same functions at DS1 / Borrelly

• Baseline plan sufficiently adequate to tolerate data loss with acceptable degradation in delivery accuracy. E.g. a 50% data loss will increase the flyby delivery error to ~26 km (1-)

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STARDUST

Remaining Efforts

• Determine need for additional camera heating, geometric calibration

• Characterize camera sensitivity and window parameter definition for imaging through periscope within E-10d

– Necessary images will be taken and processed by early-December

• Determine if OpNav backup at LMA can be provided

– NAG RFA

– Only needed if catastrophic event occurs at JPL

– Action Item on MMO, expected resolution by mid-December

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STARDUST

Opt Nav Navigation Readiness

• All operations, timelines and interfaces tested successfully at Annefrank flyby

• Same ops facilities as with ORT. Use of institutional software and/or tools certified by DS1.

• Workforce with backups and contingencies in place

– LMA Backup under Study (OpNav related RFA)

• Navigation Advisory Group (NAG) readiness review successfully completed

– Agreed that OpNav was ready, tested and qualified for Wild 2 encounter operations

– No open ISA’s

– No first time events

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STARDUST

TrainingTraining

• Lunar flyby images

• Cruise star calibration images

• OpNav @ Annefrank

– Radio + optical orbit determination using Annefrank flyby

• ORT’s

• OpNav @ DS1/Borrelly

• OpNav @ Wild2 started

• Final ORT (E-2d – E-18h) in early December