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Deep Impact Overview/Status

Deep Impact Overview/Status. Flight Readiness Review January 8, 2005 Rick Grammier Project Manager. Project Overview. Salient Features Deliver a 370 kg impactor at 10 km/s to open the interior of a comet nucleus. Target is Comet P/Tempel 1.

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Deep Impact Overview/Status

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  1. Deep Impact Overview/Status Flight Readiness Review January 8, 2005 Rick Grammier Project Manager

  2. Project Overview Salient Features • Deliver a 370 kg impactor at 10 km/s to open the interior of a comet nucleus. Target is Comet P/Tempel 1. • Impactor produces crater dependent on comet porosity and strength. • Flyby spacecraft observes impact, crater development, ejecta and final crater with visible and IR multi-spectral instruments. • On-board autonomous optical navigation used for precise targeting and control of impactor and fly-by spacecraft. • 6 month mission duration. Launch: Jan 12, 2004 Encounter: July 4, 2005. Science • To determine the differences between the interior of a cometary nucleus and its surface. • Determine basic cometary properties by observing how the crater forms after impact. • To identify materials in the pristine comet interior by measuring the composition of the ejecta from the comet crater. • Determine the changes in natural outgassing of the comet produced by the impact. • To help discover whether comets lose their ice, or seal it in over time (evidence for dormancy vs. extinction). • Address terrestrial hazard from cometary impacts.

  3. Interplanetary Trajectory6-month direct trajectory meets Tempel 1 near perihelion Launch Jan. 12, 2005 Sun X S/C Earth Orbit Earth at Encounter Tempel 1 Orbit (5.5 yr Period) Impact! July 4, 2005

  4. TCM-4 at E-96 hours TCM-5 at E-30 hours ADCS aligns ITS control frame with relative velocity E-2 min Autonav/ADCS Control E-2 hr Impactor Release E-24 hours ITM-1 E-100 min ITM-3 E-7.5 min ITM-2 E-35 min Tempel 1 Nucleus 64 kbps 2-way S-band Crosslink Flyby S/C Science and Impactor Data at 200 kbps* Flyby S/C Deflection Maneuver Release + 12 min (100 m/s) 500 km Science and AutoNav Imaging to Impact + 800 sec TCA Impact! Shield Mode attitude through Inner Coma ADCS aligns control frame with relative velocity Flyby Science Realtime Data at 200 kbps* Look-back Imaging TCA+30 min 70-m coverage from two days before release through one day past impact. All critical events timed to Goldstone-Canberra overlap, with Mauna Kea observatories in darkness at the time of impact. Flyby S/C Science Data Playback at 200 kbps* to 70-meter DSS * data rates with Reed-Solomon encoding

  5. Launch Sequence Timeline Time from Liftoff (minutes) -5 0 +5 +10 +15 +20 +25 +30 +35 +40 +45 +50 +55 +60 +70 +90 +110 +130 Launch Vehicle Events Separation* SECO 2 SECO 1 MECO Powered Flight Parking orbit coast (90 naut. mi., “rotisserie” for thermal control) Remove External Power Fairing jettison Fire spin rockets Yo-yo de-spin Spacecraft Events SCU recording engineering telemetry at 2 kbps Charge control enabled (solar array string switching) Eclipse* Spacecraft in sunlight Spacecraft in sunlight Sunlight/Eclipse Post-Sep SOE start (Sep detect) RCS Catbed Heaters ON Solar array deploy Turn ON SIRU Switch to RWA Control Turn ON RWA 1, 2, 3, 4 Open RCS latch valve, Enable ADCS Attitude Control Acquire Sun, +Y to Sun Detumble (using RCS thrusters, CSS & SIRU) 0.025 deg/sec pitch rate about +Y Acquire Sun, +Y to Sun Turn ON CRIT Heaters Turn ON TWTA 1 Beam ON Cmd SDST1 Exciter ON Communications 2-kbps engineering data (LGA) Transmitting H&S telemetry (LGA) AOS, 1 way DSN Events Canberra 34 m coverage USN coverage for playback later Turn ON DSN Transmitter AOS, 2 way * MOS Event Event times shown for earliest launch date of 12 January 2005 Separation time varies over the launch period from 33.4 to 36.9 minutes after liftoff. Eclipse duration (19.5 minutes) is reduced for later launch dates. Go for Uplink Acquisition Earliest Uplink Go for Cmd Radiate Cmd

  6. Reviews Schedule • SMARR 12/22/04 Complete • Mission Readiness Review 12/27/04 Complete • JPL GPMC 12/28/04 Complete • Mission Readiness Brief 12/29/04 Complete • Launch Site Readiness Review 12/30/04 Complete • Flight Readiness Review 1/8/05 • Mission Dress Rehearsal 1/10/05 • Launch Readiness Review 1/11/05 • Post Launch Assessment Review 2/16/05 • Encounter Risk Review 4/13/05 • Critical Events Readiness Review 6/2/05 • JPL GPMC 6/15/05 • Encounter Brief to HQ 6/22/05

  7. DI Launch Site OperationsBoeing Integrated Operations From: XMAS Flight Prog Verification Stray Volts Initiate Batt Charge (T-6) 1/5 New years (Env monitor) 2 days12/31-1/1 SA Stow Closeout Wet Weigh 1day 12/28 DI SC Erection SC Power On SC (T-8) 1/3 Mate w/ PAF, 3rd Stage 2 days 12/29-30 Canning Day 1/2 Move To KSC & Pad Preps Early AM 1/3 FSW Load 6.2.2 & Pad Functional (T-7) 1/4 Start Trickle Charge – 24hr/day 7day/wk Except 1/7 Launch Readiness Review (LRR) (T-1) 1/11 Fairing Install No Batt Trickle charge Activity (T-4) 1/7 Fairing finaling SC-Post PLF installation aliveness test Reinitiate Batt Trickle charge (T-3) 1/8 S/C Batt Trickle Charge (SUN) 1/9 Mission Dress Rehearsal/2nd Stage Prop Loading Batt Trickle charge (T-2) 1/10 Launch Countdown Batt Trickle Charge (T-0) 1/12 LV Ordnance installation SC Closeout (T-5) 1/6 Prop Sys and MST move preps S/C Final Closeout & Power On (T-1) 1/11 FRR 1/8 Long days >10 hours, 2 sh = 2 shift, 7am to 11pm (2 teams minimum) 24h = around the clock ops 24 hours per day (3 teams minimum)

  8. Previous Issues • Closure of Mission Readiness Review (MRR) action items • Completed 1/7/05 • Complete pre-launch work-to-go as briefed at MRR • Completed 1/7/05

  9. Impact of BET Change • DI did not want to accept delta-V budget hit caused by injection biases • Correcting the RLA biases required earlier launch and thus moved the separation times earlier (key to our issue) • Earlier separation impacts the S/C critical sequence • Project did not want to change the critical sequence and inherent logic that has been tested for two years • For the first launch azimuth on Jan 12th only, this meant the S/C would “sit” for several seconds after separation waiting for the critical sequence to start. • This brought in to question the viability of the fault protection response logic • Change would mean additional regeneration of products and retest for the first azimuth only, and a different set of products for all other opportunities • Not where we want to be this close to launch when the team is concentrating on preparations for operations • The decision to not use the first azimuth was the least risk approach for the mission, retained the critical sequence and fault protection logic in its as tested configuration, and (by the way) did not impact the project’s delta-V budget

  10. Current Status/Open Work • Final closure of problem report on SCU/CPU reset during pad functional test on 1/4/05 • GSE/ground configuration issue • No residual risk for flight

  11. Readiness Statement • Deep Impact is ready to continue processing for launch

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