deep impact frrjan. 8, 2005page 1 deep impact overview/status flight readiness review january 8,...

Deep Impact FRRJan. 8, 2005

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.• 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.


Interplanetary Trajectory

6-month direct trajectory meets Tempel 1 near perihelion

Launch Jan. 12, 2005

S/C

EarthOrbit

X

Earth at Encounter

Impact!July 4, 2005

Tempel 1 Orbit (5.5 yr Period)

Sun


Tempel 1Nucleus

Shield Modeattitude through

Inner ComaADCS aligns control frame

with relative velocity

Science and AutoNav Imaging to

Impact + 800 sec

ITM-1 E-100 min

ITM-2E-35 min

ITM-3E-7.5 min

Impactor ReleaseE-24 hours

Autonav/ADCS ControlE-2 hr

Flyby S/CDeflection Maneuver

Release + 12 min(100 m/s)

2-wayS-band

Crosslink

500 km

Flyby S/C Science Data Playback at 200 kbps*

to 70-meter DSS

Flyby Science Realtime Dataat 200 kbps*

Flyby S/C Science and Impactor Data

at 200 kbps*

64kbps

ADCS aligns ITScontrol frame with

relative velocityE-2 min

TCM-4 at E-96 hoursTCM-5 at E-30 hours

Impact!

Look-backImaging

TCA+30 min

TCA

* data rates with Reed-Solomon encoding

70-m coverage from two days before releasethrough one day past impact. All critical

events timed to Goldstone-Canberraoverlap, with Mauna Kea observatories

in darkness at the time of impact.

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.


Launch Sequence Timeline

0 +5 +10 +15 +20 +25 +30 +35 +40 +45 +50 +55 +60 +70 +90 +110 +130Time from Liftoff (minutes)

Launch Vehicle Events

Spacecraft Events

DSN Events

Powered Flight

MECO SECO 1 SECO 2

Fairingjettison

Fire spinrockets

Separation*

Parking orbit coast(90 naut. mi.,

“rotisserie” forthermal control)

Charge control enabled (solar array string switching)

Spacecraft in sunlight

Canberra 34 m coverage

SCU recording engineering telemetry at 2 kbps

Communications

Attitude Control

-5

RemoveExternalPower

MOS EventAOS, 2 way

Turn ON DSN Transmitter

Go for Uplink AcquisitionGo for Cmd

Radiate Cmd

Spacecraft in sunlight

Yo-yode-spin

Post-Sep SOE start (Sep detect)

Solar array deploy

Open RCS latch valve, Enable ADCSDetumble

(using RCS thrusters,CSS & SIRU)

Acquire Sun, +Y to Sun

Turn ON CRIT Heaters

Turn ON TWTA 1Beam ON Cmd

SDST1 Exciter ON Transmitting H&S telemetry (LGA)

RCS Catbed Heaters ON

Turn ON RWA 1, 2, 3, 4

Sunlight/EclipseEclipse*

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.

*

2-kbps engineering data (LGA)

Acquire Sun, +Y to Sun

0.025 deg/sec pitch rate about +Y

Turn ON SIRUSwitchto RWAControl

Earliest Uplink

AOS, 1 way

USN coveragefor playback later


Reviews Schedule

• SMARR 12/22/04 Complete

• Mission Readiness Review 12/27/04Complete

• 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 Review2/16/05

• 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


DI Launch Site OperationsBoeing Integrated Operations

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)

Move To KSC &

Pad PrepsEarly AM

1/3

Move To KSC &

Pad PrepsEarly AM

1/3

DI SC ErectionSC Power

On SC (T-8)1/3

DI SC ErectionSC Power

On SC (T-8)1/3

FSW Load 6.2.2 & Pad Functional

(T-7)1/4

FSW Load 6.2.2 & Pad Functional

(T-7)1/4

Flight Prog Verification Stray VoltsInitiate Batt

Charge(T-6)1/5

Flight Prog Verification Stray VoltsInitiate Batt

Charge(T-6)1/5

Fairing finaling SC-Post PLF installation

aliveness testReinitiate Batt Trickle charge

(T-3)1/8

Fairing finaling SC-Post PLF installation

aliveness testReinitiate Batt Trickle charge

(T-3)1/8

Prop Sys and MST

move prepsS/C Final

Closeout & Power On

(T-1)1/11

Prop Sys and MST

move prepsS/C Final

Closeout & Power On

(T-1)1/11

Mission Dress Rehearsal/2nd Stage Prop

LoadingBatt Trickle

charge(T-2)1/10

Mission Dress Rehearsal/2nd Stage Prop

LoadingBatt Trickle

charge(T-2)1/10

Launch Readiness Review (LRR)(T-1)1/11

Launch Readiness Review (LRR)(T-1)1/11

Launch CountdownBatt Trickle

Charge(T-0)

1/12

Launch CountdownBatt Trickle

Charge(T-0)

1/12

Start Trickle Charge – 24hr/day 7day/wk

Except 1/7

From: XMAS

Fairing Install

No Batt Trickle charge

Activity(T-4)1/7

Fairing Install

No Batt Trickle charge

Activity(T-4)1/7

Canning

Day1/2

Canning

Day1/2

Mate w/ PAF, 3rd

Stage2 days

12/29-30

Mate w/ PAF, 3rd

Stage2 days

12/29-30

New years(Env

monitor)2 days

12/31-1/1

New years(Env

monitor)2 days

12/31-1/1

LV Ordnance installation SC

Closeout(T-5)1/6

LV Ordnance installation SC

Closeout(T-5)1/6

SA StowCloseout

Wet Weigh1day

12/28

SA StowCloseout

Wet Weigh1day

12/28

FRR

1/8

S/C Batt Trickle Charge

(SUN)1/9

S/C Batt Trickle Charge

(SUN)1/9


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


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


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


Readiness Statement

• Deep Impact is ready to continue processing for launch

deep impact frrjan. 8, 2005page 1 deep impact overview/status flight readiness review january 8,...

Documents