THEMIS: RESOLVING THE PHYSICS OF ONSET AND EVOLUTION OF SUBSTORMS

OBJECTIVE: Study energy releases from Earth’s magnetosphere known as substorms (magnetic phenomena that intensify auroras near Earth's poles)

RATIONALE: Provide scientists with important details on how the planet's magnetosphere works, specifically:

• better understanding of the physical instability (trigger mechanism) for magnetospheric substorms

• comprehensive look at the onset of substorms and how they trigger auroral eruptions

Fundamental to our understanding of space weather

Mission Science

Mission ArchitectureConstellation of 5 satellites (probes), each carrying identical instrumentation

• fluxgate magnetometer (FGM)

• electrostatic analyzer (ESA)

• solid state telescope (SST)

• search coil magnetometer (SCM)

• electric field instrument (EFI)

Line up in magnetosphere every 4 days

• launched into “cruise phase” 33 hr orbit

• maneuver into 1, 2 and 4 day orbits for winter season 2008

Conjunction with ground based instruments

• 20 northern sites with all sky imagers and magnetometers

January 5, 2007 THEMIS Mission Readiness Review 3

Standard Delta 10 ft. Fairing Static Envelope

3712 PAF

Probe Carrier Assembly (PCA = 5 Probes + Probe Carrier) on L/V

Probe Carrier Assembly (PCA = 5 Probes + Probe Carrier) on L/V

THEMIS Launch Configuration

THEMIS Launch Configuration

Probe Carrier Assembly (PCA) on Delta 3rd StageProbe Carrier Assembly (PCA) on Delta 3rd Stage

Launch ConfigurationDedicated launch

accommodated within standard Delta 7925-10 vehicle configuration and services

10’ Composite Fairing required to accommodate five Probes on the Probe Carrier in the “Wedding Cake” configuration

PC stays attached to Delta 3rd stage after probe dispense

Each probe dispense from the PCA is coordinated with but independent of the other probes

No single probe anomaly precludes dispense of remaining probes

Star 48 3rd Stage

January 5, 2007 THEMIS Mission Readiness Review 4

Launch Vehicle Overview• Vehicle Configuration: Delta 7925–10C• Launch Site: Eastern Range (ER), SLC-17B at

Cape Canaveral Air Force Station (CCAFS)• Mission Specifics:

– Perigee: 435 km, Apogee: 91845 km– Orbit Inclination: 16 degrees– Spacecraft (SC) Mass (will not exceed)

» 829 kg (2832.94lb) 775.60 kg actual– STAR 48B Motor

» Nutation Control System» Yo-Yo de-spin system

• Spin rates: – During Third Stage operation - max 70 rpm– S/C after spin-down and separation - 162 rpm

• Mission Unique– 3712 Bolted PAF– Sep System (at PAF/PC Interface)

• Non-Standard Services– Category 1 Analysis

» (1st 7925-10C ER)– Five - 24” Doors– Two 61 pin connectors– Fairing Cleaning to VC 6

• Separation System provided by THEMIS Spacecraft, contracted through Launch Services Program (LSP)NASA Launch Service (NLS) Contract

January 5, 2007 THEMIS Mission Readiness Review 5

Depletion Burn:Removes Stage 2 fromvicinity of spacecraft,while lowering Stage 2 perigee altitude andorbit inclination

Flight Profile

Liftoff

MECOt = 263.3 secAlt = 69.0 nmiVI = 20,060 fps

Second Stage Ignitiont = 276.8 secAlt = 72.9 nmiVI = 20,068 fps

Fairing Jettisont = 281.0 secAlt = 74.1 nmiVI = 20,103 fps

SECO 1t = 593.5 secAlt = 101.9 nmiVI = 25,923 fps

ORBIT:100 x 304 nmi28.50 deg inclination

Second Stage Restartt = 3859.4 secAlt = 282.7 nmiVI = 24,662 fps

SECO 2t = 3915.1 secAlt = 280.6 nmiVI = 25,778 fps

ORBIT:280 x 825 nmi26.58 deg inclination

TECOt = 4091.6 secAlt = 305.2 nmiVI = 33,975 fps

Separate Probe At = 4380.1 secAlt = 658.6 nmiVI = 32,368 fps

Orbit:235 x 49,592 nmi16.00 deg inclination-40.00 deg arg of per

SRM Impact SRM Impact

SRM Jettison (6)t = 66.0 / 67.0 secAlt = 9.9 / 10.2 nmiVI = 3,231 / 3,269 fps

SRM Jettison (3)t = 131.5 secAlt = 31.3 nmiVI = 8,018 fps

Third Stage Ignitiont = 4005.1 secAlt = 281.0 nmiVI = 25,775 fps

Note: Values shown are for 15-28 Feb 2007 launch

Simple, Robust, Fault Tolerant System: • Power positive in all attitudes with

instruments off (launch, safe hold modes)

• Passive spin stability achieved in all nominal and off-nominal conditions

• Passive thermal design using MLI and thermostatically controlled heaters tolerant of longest shadows (3 hours)

• S-Band communication system always in view of earth every orbit at nominal attitude. In view for greatest part of orbit in any attitude

• Monoprop blow down RCS (propulsion) system is self balancing on orbit

Probe Bus Design

PAF Adapter Ring/Tube & Attach to Launch Vehicle

PAF Adapter Ring/Tube & Attach to Launch Vehicle

Main DeckMain Deck

Center SpoolCenter Spool

(4) Lower Probe

Standard Separation

Fittings

(4) Lower Probe

Standard Separation

Fittings

(1) Upper Probe Standard Separation Fitting(1) Upper Probe Standard Separation Fitting

(8) External Struts(8) External Struts Probe Carrier (PC)Probe Carrier (PC)

• Simple probe carrier utilizes– Machined aluminum structure– Standard heritage payload attach fittings

utilize pyro- actuated clampband– Straight-forward umbilical interconnect

harness

• Detailed design supported by analysis and full system test– NASTRAN model to recover material

stresses and fundamental frequencies– Base drive analysis used to verify

strength and recover component loads– Coupled Loads Analysis– PCA Vibration/Acoustic Test

• Probe layout on carrier maximizes static and dynamic clearances– Design is the best balance between

deployment clearances and probe mass

First Axial Mode: 48.27 Hz

First Lateral Mode:18.29 Hz

Probe Carrier Fundamental Natural Frequencies:

Displacements Not to Scale

Probe Carrier Design

Probe Bus SystemsProbe Structure

• Carbon Composite, Total Mass 126 kg

Payload Interface• Single, simple RS-422 Interface between UCB

Instrument Data Processor (IDPU) and Swales Bus Avionics Unit (BAU)

RF Communications• S-band Transponder, 5 W• Hexagonal Microstrip Patch Antenna• Toroidal Antenna Pattern, LHCP• 10 Telemetry Rates: 1.024 - 1048.576 kbps• Command Data Rate: 1.0 kbps

Thermal Subsystem• Passive Hot Biased System with Local

Radiators• Thermostatically Controlled Heaters

Power System• Total Power: 40 W• Solar Panels: 6 Sets, Body Mounted• Solar Cells: GaAs Triple-junction• Battery: Lithium Ion, 28 V, 11.8 Ah• Charge Control: Direct Energy Transfer

Propulsion System• Hydrazine Blow-down System• 4 Thrusters

2 Axial, 2 Tangential, 4.4 N• 2 Propellant Tanks

Total Fuel Load: 49.0 kgMEOP: 2750 kPa at 40 C

• Repressurizing Tank, He• Latch and Solenoid Valves

Attitude Control System• Spin-stabilized Platform• Open Loop Spin Control, 20 rpm• Miniature Spinning Sun Sensor• Flux Gate Magnetometer• Inertial Reference Units (2)• Attitude Control Via Propulsion System

Command and Data Handling• ColdFire Processor, 8.388 MHz

• RTEMS Operating System

• Bulk Memory, SDRAM, 64 MBytes

• CCSDS V1 TLM and CMD Formats

Fuel Tank

ESA

EFI SPB

Thruster T1

EFI Axial Booms (2, Stowed)

BatteryBAU

Repress Tank

Miniature Sun Sensor

Transponder

Thruster T2

IDPU

Fuel Tank

Antenna

EFI SPB

EFI SPB

Thruster A1

Thruster A2

AEB

Gyros

Probe Configuration

Probe Block Diagram

DirectPower

ShuntRegulation

UmbilicalSAS

Interface

PowerDistribution

UplinkCommandInterface

CommandVerification

LVPS5V, 3.3V,

2.5V

DiscreteCommandGenerator

DownlinkTelemetryInterface

TelemetryProcessor

HardwareCmd

Interface

TelemetryLogic /FIFO

RSEncoding

+28V to IDPU,XPNDR,&Heaters

BatteryOff Cmd

PowerControlModule

LVPS+5V

SepInterface

HardlineTlm

+28V Bus

To SunSensor

LVPS+/-5V

ToGyros

HardlineCmd

Cmd/Status

Interface

Cmd/Status

Interface

SeparationCommand

SeparationInputs

33.554MHz

FPGA

inst tlminst status

8.388 MHz

512 KBEEPROM

PowerSwitch

Refresh

Baud Clk

4/25/04

Ctrl/Status 1

Ctrl/Status 2

Reg Reg

P-S

Reg

P-S

RS-422

Clock1PPS

ColdFireProcessor

512 KBRAM

64 KBPROM

64 MBBulk

Memory

CommunicationInterfaceModule

ProcessorModuleRS-422RS-422

D/L TLM

32-8

Reg

2.1Mbps

RS-42254AC

IDPUSun

Pulse8.388MHz

RS-422

S-P

Reg

Clock/TimerCircuitry

inst cmdss/c statustime

RS-422

UARTXMitter

InstrumentData Processing

Unit (IDPU)

Solar Array

SunSensor

TransmitterReceiver

DiplexerThrusters &

Latch Valves

PressureTransducers

S-BandAntenna SST

SCM

ESA

FGM

EFIEFI EFIEFIEFIEFI

+28V

Thermistors& PRTs

LV Hardline Command

+28V

+5V

+28V

SolidState

Gyro(2)

+5V -5V

RS-422RS-422

Battery

BatteryRelay

BatteryOn Cmd

Attitude Control System

ACS Sensors

Actuators

Bus Avionics Unit (BAU)

Flight Software

Ground Data System

SS Interface Electronics

IRU Interface Electronics

Sun Sensor

Three-Axis Magnetometer

(FGM Instrument)

Y-Axis Angular Rate

Sun Crossing Pulse Sun Sensor Processing

at sun crossing

TAM Processing at 1 Hz

3-Axis Magnetic Field

IRU Processing at 1 Hz

w/ 20 Hz IRU dataACS

Telemetry Processing

at 1 Hz

Thruster Output

at 20 Hz

Thruster Operations Monitoring

GTDS Orbit Detemination

MSASS Attitude

Determination

GMAN Maneuver Planning

Disable Thrusters

Thruster Commands

Limits

Thruster Control Electronics

Start Count, Stop Count

ThrusterThruster

ThrusterThruster (2 Axial, 2 Side)

Rate Gyro

Thruster Valve

Open/Closed

IRU (2 single-axis)

X-Axis Angular Rate

Spin rate, Sun Aspect Angle, Sun Crossing Time

Instrument Data Processing Unit

(IDPU)

Sun Aspect Angle

Status Bit

Status Bit

Spin Rate

Limit Monitoring at 1 Hz

Thruster Command Processing

at sun crossing

Start & Stop Buffer

Spin Axis, Cone Angle

Reaction Control System• Four 4.4-N Thrusters for maneuvers -2 Axial, 2 Tangential

• Latch valves opened right after launch, prior to first maneuver

• Redundant Cat-beds used prior to all firings to avoid cold starts

• Isolation valve opened right before pyro valve is fired at specific pressure for system repress:

Two axial thrusters (A1, A2) for major orbit changes and attitude control

Two tangential thrusters(T1, T2) for spin control

and minor orbit changes

Thruster Placement

RCS Operational Modes

Maneuver Type

Thrusters InvolvedDepiction of

Operational ModePurpose of Maneuver

Axial ThrustA1 and A2

Continuous Firing

Perigee or Apogee Change or Combined In-

plane and Out-of-plane Orbit Change

with Stowed EFI Booms

Side ThrustT1 and T2 Pulsed

Firing

Perigee or Apogee Change

with Deployed EFI Booms

Beta Thrust

A1 and A2 Continuous Firing Alternating With

T1 and T2 Pulsed Firing

In-plane and Out-of-plane Orbit Change with

Deployed EFI Booms

Attitude Precession

A1 or A2 Pulsed Firing Attitude Change

Spin-up / Spin-down

T1 or T2 Continuous or Pulsed Firing

Spin Rate Adjustment

Instrument SystemsElectric Field Instrument (EFI)

• Three dimensional experiment• Measures electric field• 4 spin-plane spherical sensors mounted on

20m deployable cable • 2 axial tubular sensors mounted on 4m

deployable stacer element• Experiment and booms built at UCB

Fluxgate Magnetometer (FGM)• Single triaxial fluxgate magnetometer• Mounted on 2 meter deployable boom• Measures low frequency magnetic field• Sensors built by TUBS (Germany)• Electronics built by IWF (Austria)• Boom built by UCB• Magnetic cleanliness led by UCLA

Search Coil Magnetometer (SCM)• Single unit, three orthogonal u-metal rods• Mounted on 1 meter deployable boom• Measures high frequency magnetic field• Sensor, Electronics built by CETP (France)• Boom built by UCB

Electrostatic analyzer (ESA)• Single unit, mounted to IDPU• Measures thermal plasma; electrons and

ions in the range 5-40 KeV • Built by UCB, nearly identical to the ESA

Instruments on the FAST Spacecraft

Solid State Telescope (SST)• Two double-ended telescope units• Measures super-thermal plasma; electrons

and ions in the range 30-300 KeV • Built by UCB, similar to WIND

Instrument Data Processing Unit (IDPU)• Provides the electronic interface between

the Probe and the Instrument sensors • Collects and formats all instrument data,

and controls instrument operations • Multi-slot 6U VME chassis• Consists of 6 boards (LVPS, PCB, DCB,

FGE, DFB, BEB, DAP)• 8085 Processor• 256MB SDRAM Storage• ~2x loss-less compression

Instrument Configuration

Deployed Configuration

Instrument Suite −Stowed Configuration

January 5, 2007 THEMIS Mission Readiness Review 17

Mass Status

• < 2% mass deviation between Probes (requirement)• Dry Mass Margin: 4.5% (Worst case)

Power Status• Probe CBE: 38.7 W• Probe Capability: 40.60 W• Probe Margin: 8.8% (First 3-hour Eclipse Season)

4.9% (Second 3- hour Eclipse Season)

Resources

Mass(Kg) F1 F2 F3 F4 F5Measured 78.04 77.62 76.72 76.72 78.08NTE 81.80 81.80 81.80 81.80 81.80Margin 3.76 4.18 5.08 5.08 3.72% 4.6% 5.1% 6.2% 6.2% 4.5%

Mass History• Mass

– Probe Dry Mass was limiting mass resource – Probe Dry Mass Current Best Estimate (CBE): 77.5 kg– Probe Dry Mass Not to Exceed (NTE) due to Delta-V requirement: 81.8 kg– All Probes measured during spin balance, <1% variability between Probes– Probe Dry Mass Margin: 5.6%

SPACECRAFT MASS

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

Ph

ase

A

8/0

3

10

/03

12

/03

2/0

4

4/0

4

6/0

4

8/0

4

10

/04

12

/04

2/0

5

4/0

5

6/0

5

8/0

5

9/0

6

Date

Mas

s (

kg)

Probe Dry Mass NTEProbe Dry Mass CBEProbe Bus CBEInstrument CBE

Power History• Power

– Late increase in Probe power was from additional heater power predicted from updated thermal model.

– Late increase in capability was based on measured S/A LAPSS performance data for F2 S/As, coupled with BEAST time history analysis.

SPACECRAFT POWER

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

PhaseA

8/03 10/03 12/03 2/04 4/04 6/04 8/04 10/04 12/04 2/05 6/05 8/05 10/05 12/05 2/06

Date

Po

wer

(W

)

P1 Capability - Daylight Pow er

P1 Probe CBE

Probe Bus CBE

Instrument CBE

Probe CBE: 36.6 W

Probe Capability: 40.35 W

Probe Margin: 10.2%

Ground Based Observatories

Ground Based Observatories • 20 GBO (GMAG and ASI) units• Automatic Data Collection and Archiving• Remote Commanding and Diagnostics• Expect to be Fully Functional at Winter 2008

Courtesy H.Frey, UCB

GeographicLongitude 324°

Geographic Longitude 195°

GeomagneticNorth Pole

GeographicNorth Pole

Ground System Diagram

Ground System Elements•Ground Stations

•Ground Network

•Space Network

•Mission Operations Center

•Science Operations Center

•Flight Dynamics Center

Including•Mission Design

•Orbit & Attitude Determination

•Maneuver Planning

•Limit Detection and Notification

•Network Security

January 5, 2007 THEMIS Mission Readiness Review 22

Ground Stations

Ground StationStation

DesignatorFigure of

MeritLocation Function

Berkeley, CA BGS 11-m 24.0 dB/K37.879° N 122.243° W

Primary TLM/CMD/TRK

Wallops Island, VA WGS 11-m 23.0 dB/K37.925° N75.476° W

Secondary TLM/CMD/TRK

Merritt Island, FL MILA 9-m 1/2 21.6 dB/K28.508° N80.693° W

Secondary TLM/CMD/TRK

Santiago, Chile AGO 9-m 21.6 dB/K33.151° S70.668° W

Secondary TLM/CMD/TRK

Hartebeesthoek, SA HBK 10-m 20.4 dB/K25.883° S27.708° E

Secondary TLM/CMD/TRK

Mission Supported by 5 Ground Stations• Ground Stations: BGS, WGS, MILA, AGO, HBK• GN, SN and FDF Support Documented in PSLA• All Stations Have Successfully Flowed Data with MOC

January 5, 2007 THEMIS Mission Readiness Review 23

Mission Operations Center

BGS Antenna, Equipment Racks and FOT Workstations at the Mission Operations Center

January 5, 2007 THEMIS Mission Readiness Review 24

UCB MOC

Integration and Test Flow• Instruments delivered to UCB for Instrument Suite Integration

– Integration to IDPU (BAU simulator is used)– Interface tests and self-compatibility, complete functional testing before/after environments– Environmental Test Sequence on Instrument Suite

• Probe Buses delivered to UCB for Probe/Instrument Suite Integration– Component-wise integration of Instrument Suite with Probe Bus– Interface tests and self-compatibility– RF Performance and End-to-End Mission Operations Center testing– Comprehensive Performance Tests, Mission Simulations

• 1st Integrated Probe to JPL for Environmental Tests (Pathfinder)– Magnetics, EMI/EMC– Vibration– Thermal Vacuum (Cycling and Extended Balance)

• Remaining 4 Probes and Probe Carrier (PC) to JPL for Environmental Tests– Probe Carrier Assembly (PCA - PC and 5 Probes) Vibration and Acoustic Test– Mass Properties and Spin Balance– Thermal Vacuum– Magnetic Survey

• Probes and Probe Carrier to Cape– Probes Fueled, mass properties– Final PCA build-up and spin balancing

Environmental Test

Environmental Test Matrix (ETM):

NOTES: A = Analysis Q = Qualification unit only

T = Test I = Inspection

TS = Test on 1st unit only, rest by similarity W = Weigh

TL = Limited Test

OTHER

COMPONENT (ITEM)

QU

AN

TIT

Y

SU

PP

LIE

R

ALI

GN

ME

NT

MO

DA

L S

IGN

AT

UR

E/S

UR

VE

Y

SIN

E B

UR

ST

RA

ND

OM

VIB

RA

TIO

N

SIN

E V

IBR

AT

ION

AC

OU

ST

IC

PR

OO

F T

ES

T

CLA

MP

BA

ND

SH

OC

K

VE

NT

ING

/PR

ES

SU

RE

PR

OF

ILE

MA

SS

PR

OP

ER

TIE

S

ME

CH

IN

TE

RF

AC

E

SP

IN B

ALA

NC

E

INT

ER

FA

CE

VE

RIF

ICA

TIO

N

CO

ND

UC

TE

D E

MIS

SIO

NS

CO

ND

UC

TE

D S

US

CE

PT

IBIL

ITY

RA

DIA

TE

D E

MIS

SIO

NS

RA

DIA

TE

D S

US

CE

PT

IBIL

ITY

TH

ER

MA

L V

AC

UU

M

TH

ER

MA

L B

ALA

NC

E

# O

F T

HE

RM

AL

CY

CLE

S

ES

C A

ND

GR

OU

ND

ING

DC

MA

GN

ET

ICS

AC

MA

GN

ET

ICS

BA

KE

OU

T

RA

DIA

TIO

N

Instrument Suite 6 UCB T TS TS T 6 TS TInstruments and IDPU 1 TUBS T T A T T A W I T T 2 T M T AProbe Subsystems SAI T T A T/A A/T A T Q/A A W I T TS TS TS TS T 8 T M T A Integrated Probe F2 1 UCB T T T T T T W I T T self self T T T T 4 T M T T Integated Probes F1, F3-5 4 UCB T T T T T W I T T self self TS TS T TL 4 T M T TProbe Carrier 1 SAI T T A W IProbe Carrier Assembly 1 SAI T T A W I T

CONTAMINATIONHARDWARE MECHANICAL ELECTRICAL THERMAL

Environmental Test• Thermal Vacuum

• Instruments: 2 cycles Instrument level, 6 cycles Instrument Suite level. • Probe Bus: 8 cycles component level.• Probe System: 4 cycles on all probes. Extended thermal balance completed on 1st Probe. Limited

Thermal Balance on subsequent probes.

• Vibration/Shock/Acoustics• Instruments: Qualification vibe on ETUs, Acceptance vibe on all flight units• Probe Bus: Qualification/Acceptance vibe on ETU/flight or Protoflight vibe on 1st flight unit• Probe System: Protoflight vibe on 1st Probe. Sine vibration and acoustics on PCA. 2 shock tests on

1st Probe (1 complete, 1 after PCA acoustics), 1 shock test on subsequent probes after PCA acoustics. 1 sep test on ETU sep system after PCA Mass Dummy Vibration.

• EMI/EMC• Instruments: Conducted EMC on FM1 Instrument Suite, self-compatibility on all Suites• Probe Bus: Conducted and radiated EMC on 1st BAU and transponder• Probe System: Radiated EMC completed on 1st Probe at JPL. EMC comparison checks and self-

compatibility tests during probe integration.

• Magnetics• Instruments and Probe Bus: Measurements and deguass (if necessary) prior to Integration• Probe System: For 1st Probe, DC Magnetics in JPL coil facility (powered and un-powered probe

states), AC magnetics during EMC. For all Probes, final DC magnetics check.

Thermal Vac Test Plan

January 5, 2007 THEMIS Mission Readiness Review 29

Environments

Thermal Vacuum

Acoustics

Spin Balance

EMC

VibrationMagnetics

January 5, 2007 THEMIS Mission Readiness Review 30

Probe Carrier Assembly during Vibration

Installation of Thermal Vacuum Shrouds

Probe on GSFC Spin Balance Miller Table

Two Probes Ready for TV Testing

Environments

January 5, 2007 THEMIS Mission Readiness Review 31

Probe Processing

Bolt Cutter Installation

Performance Tests

Solar Array Illumination

Delivery to ASO

January 5, 2007 THEMIS Mission Readiness Review 32

Probe Fueling Preps

FM2/FM3 Thermal Vacuum

Vibration

Thermal Vacuum

Acoustics Spin Balance

Storage

Dry Weigh & Pressurize

Ready for Fuel

January 5, 2007 THEMIS Mission Readiness Review 33

Carrier Processing

Vibration Acoustics Spin Balance

Storage

PC Unload

SSS Installation

Ready for Probes

January 5, 2007 THEMIS Mission Readiness Review 34

THEMIS Probe Carrier Assembly (PCA) in Launch Configuration

Launch Configuration

January 5, 2007 THEMIS Mission Readiness Review 35

THEMIS was originally scheduled to launch on October 19th, 2006:

– delays caused by workmanship problems with Delta II second stages delayed launch to Feb 15th, 2007

– weather conditions on Feb 13th delayed fueling of the second stage, launch pushed back 24 hours

– on February 16th, launch was scrubbed in a hold at the T-4 minute point in the countdown due to the final weather balloon reporting a no-go condition for upper level winds

– 24-hour turnaround procedure was initiated, targeting a new launch window between 23:01 and 23:17GMT on February 17th

Launch Delays…

January 5, 2007 THEMIS Mission Readiness Review 36

THEMIS successfully launched at 6:01 pm EST, February 17th, 2007:

– Probes separated from the launch vehicle approximately 73 minutes after liftoff

– 8:07 p.m. EST, mission operators at the University of California, Berkeley, commanded and received signals from all five spacecraft, confirming nominal separation status

– (then didn’t hear from Probes for 33 hours… )

Launch!

January 5, 2007 THEMIS Mission Readiness Review 37

LEO Acquisition

LEO AcquisitionMultiple Ground Assets Had Good View Following LaunchProbe Attitude Around 1:30 MET is Poor for Telemetry Probes Contacted at 4Kbps for 5 Minutes each from 1:20 to 1:40

January 5, 2007 THEMIS Mission Readiness Review 38

LEO Operations

LEO Operations• State Vector Delivered to UCB via email @ SECO-2 (65min)• Monitoring of Probe Separation via TDRSS

– Top Probe was commanded to transmit at T+70 mins– Separation occurred at T+73 minutes – All Probes were recording Engineering Data– Separation was recorded by each Probe individually– Engineering Data dumped in later passes

• Probes Are Released at Good Sun Angle, Power Positive– 43 degrees Side to Sun

Probe A Released First

Probes B−E Released Simultaneously 3 s Later

All Probes Independent of Each Other

January 5, 2007 THEMIS Mission Readiness Review 39

Mission Profile