THEMIS RRConstellation Operations − 1UCB, June 28, 2007 THEMIS Constellation Operations Manfred...

THEMIS RR Constellation Operations − 1 UCB, June 28, 2007

THEMIS Constellation Operations

Manfred BesterTHEMIS Mission Operations Manager

University of California at Berkeley


Agenda

Agenda• Mission Profile Update• Mission Readiness Testing• Launch & Early Orbit Campaign• Flight Systems Performance & Status• Instrument Deployment & Commissioning• Coast Phase• Ground Systems Performance & Status• Telemetry Data Recovery & Processing• Anomalies• Constellation Status Summary• Configuration Management• Staffing & Engineering Support• Updated Flight Rules


Mission Profile Update


Mission Readiness Testing

Mission Readiness Testing• Extensive Mission Readiness Test Program

– See MRT Spreadsheet for Details

• Training & Simulation Sessions– Many Training and Simulation Sessions Including Greencard Exercises to

Prepare the UCB Operations Team– Conducted by Contractors (B. Stroozas, C. Deyarmin)

• Mission Simulations & Dress Rehearsals18-Jan-2007 MD0 Simulation – MOC with UCB/Swales Team19-Jan-2007 MD1 Simulation – MOC with UCB/Swales Team02-Feb-2007 MD0 Simulation – MOC with UCB/Swales Team,

UCB@KSC03-Feb-2007 MD1 Simulation – MOC with UCB/Swales Team,

UCB@KSC05-Feb-2007 MD0 Simulation – MOC, KSC, NOM, GN/SN09-Feb-2007 MD0 Simulation – MOC, KSC, NOM, GN/SN, UCB@KSC13-Feb-2007 MD0 Simulation – Launch Countdown with KSC, Boeing16-Feb-2007 MD0 Countdown to L−4 min Scrub


THEMIS Mission Data Flows

JPL I&T Facility

Berkeley Mission Operations Center

White SandsComplex

Compatibility Test Van

GSFC NMC

Wallops Ground Station

Different Routes for End-to-end Data Flows Between Probes and GS Elements

BerkeleyGround Station

THEMISProbe

SecureIntranet

TDRS

Secure VPN Tunnel via Open Internet

Notes: Open (1), Restricted (2) or Closed (3) IONet

Open IONet

Hartebeesthoek Ground Station

Dial-up ISDN Line

Santiago Ground Station

Merritt IslandGround Station

KSC & Astrotech

UCB I&T Facility

(3)

(3)

(1)

(2)

(3)


MOC Console Assignments


Launch & Early Orbit Campaign

Launch & Early Orbit Campaign


Launch Campaign

Launch Campaign• Launch Team Located at KSC and UCB

– UCB, Swales, Hammers and GSFC Team Members– Communications via 3 Voice Loops

• Pre-launch Data Flows– Launch Pad and GN/SN to MOC– MOC Activities Started at L-9:30– Data Flow Tests with GN/SN– Probes Powered On at L-7:00– Blockhouse Cleared at L-4:30

• Go/No-Go Polls– First Go/No-Go Poll at L-4:00– Final Go/No-Go Poll at L-0:20– THEMIS Configured for Launch

at L-0:05• Real-time Data Flows from All

Probes to MOC Until Lift-off


Launch Campaign

THEMIS Launch• Launch Site: CCAFS SLC-17B• Launch Vehicle: Delta II 7925-10• Lift-off Time: 17-Feb-2007 23:01:00.384 UTC

(at Opening of 19-min Launch Window)

• Target Orbit: 435.0 × 91845.2 km at 16.0 deg


Launch from MOC Perspective

FOT in Action

T−00:00:01 and Lift-off!

Post-launch Briefing

First BGS Contact


Flight Profile


Probe Separation

Confirmation of Probe A Separation via TDRS West:

2007/049 00:14:00 UTC

First TDRS Contact via Blind Acquisition

Forward Link: 1.000 kbpsReturn Link: 1.024 kbps


Launch & Separation Trends

Filtered IRU X and Y Output

Separation Event

THEMIS A & B Launch and Separation Trend Plots

SA Panel 1 Temp (C)SA Top Temp (C)S-band Antenna Temp ©Transmitter Temp (C)

Lift-off

Partial Lunar Shadow


Initial Acquisition via GN

Initial Acquisition via Ground Network• Insertion Attitude Was Difficult for Ground Network Coverage

– Probes Were Oriented with Antennas Pointing Away from Ground Stations (Known Before Launch)

• All Telemetry Links Appeared Weaker Than Expected– Initial Concerns of Continuing Degradation Were Dispersed Later

– Overall Drop in Signal Level Plus Variations with Spin Phase

• Causes for Lower Than Expected Performance– RF Power Dissipation Within Antenna (20% instead of 10%)

– Ripple in Antenna Patterns as Function of Antenna Look Angles– Spin Phase and Elevation Angle Relative to Spin Plane

– Magnitude of Ripple Determined by Characterizing Telemetry Link Performance as Function of Probe Attitude and Range

• Ground Stations Had Difficulties to Lock on Weak Signals– Equipment Characteristics and Configuration Does Not Match

Assumptions Used to Develop Telemetry Link Budgets


Initial Acquisition – Cont.

Predicted Spacecraft Antenna Aspect Angle (Top Panel) and Resulting Telemetry Link Margin (Bottom Panel)

Based on Nominal Insertion Attitude

Initial BGS View Period

Data Rate 4K

01:00:00 – 13:00:00 MET


Initial Acquisition – Cont.

Recorded Signal Strength from Initial BGS Passes with THEMIS B, C, D, E, A

Intermittent RF and Data Lock on THEMIS B Only

Recorded Signal Strength from Second BGS Pass with THEMIS A

Solid RF and Data Lock


Power & Thermal Issues

Power & Thermal Issues• Insertion Attitude Caused Concerns

– Spin Axis to Sun Angle: 45 - 50 deg

– Solar Panels Generate More Power Than Expected– Shunts in Power System Cannot Dissipate Energy When Top Solar

Panel Illuminated– Turned on Catalyst Bed Heaters for Mitigation Prior to IDPU Power-on

– Battery Overvoltage Protection (OVP) Trips– Detected OVP Trip First on THEMIS A during Separation Event Pass– Team Was Concerned that Battery Overcharging Might Occur– OVP Trips Turn All Digital Shunts On, Removing Power from Solar

Array Strings 1, 2 and 3 Until Battery Voltage Drops to 32.2 V

– High Antenna Temperature (>70 C) When Transmitter Turned On

• Transmitter Operations– Limited Due to Antenna Heating Up, Especially Near Perigee


Vector Delivery

Vector Delivery from Boeing• UCB Received Post-launch AAM Vector

– Based on Measured Performance of LV Second Stage and Predicted Performance of Third Stage

– Very Close Agreement with Pre-launch Predicts

– USSPACECOM Provided TLEs that Appeared to Match the AAM

• Orbital Period– Expected Orbital Period Was 1999 ± 180 min (3-σ)

– Achieved Orbital Period Was 1884 min (1999 - 115 min)

(OD Solution Provided by GSFC/FDF on 20-Feb-2007)


Insertion Orbit

Successful Initial Set of Round-robin State-of-health Checks via BGS


Insertion Orbit

First Negative Acquisition at Apogee via HBK


Insertion Orbit

Difference Between Predictive and Definitive Insertion Orbits


Spacecraft Emergency

Declared Spacecraft Emergency• Declared Spacecraft Emergency at 2007/050 03:30:00 UTC

– No Communications with Any Probe for 17 hours

– Concerns with Power and Thermal Issues in Insertion Attitude

• Additional Assets Brought Online– GSFC/FDF Generated Acquisition Vectors for DSN Stations

• GSFC/FDF Generated First Valid OD Solution– Initial Two-way Doppler Tracking Data Were Sparse Since Both

BGS and WGS Had Difficulties to Lock onto Weak Signals

– Used Crude Angle Data from WGS to Enhance Tracking Data Set

• Probes Reacquired via HBK After 28 Hours– Confirmed Good State of Health of All Five Probes

• Continued to Shadow Track with DSN Stations for Another Day– DSS 46 (Madrid), DSS 66 (Canberra) and DSS 27 (Goldstone)

• Emergency Terminated at 2007/051 11:45:00 UTC


Insertion Orbit

Successful Reacquisition via HBK Based on GSFC/FDF’s First OD Solution


First Orbit Solution

Post-launch Orbit Configuration – Dispersed at L + 6.5 d


Flight Systems Performance

Flight Systems Performance


Power Subsystem

Power Subsystem Performance• Power Generation Much Better Than Expected

– Shunts Cannot Dissipate Enough Power When Instruments Are Turned Off

– Used Catalyst Bed Heaters Initially to Dissipate Excess Power

– Battery State of Charge Typically Maintained Above 90%

(Full Capacity 11.8 Ah)

• Overvoltage Protection Trips Turned Out to Be False Alarms– Initially Thought to Be Related to Transmitter Power-on Events

– Later Shown to Be Related to RTS Execution

– Reason Unknown


Thermal Subsystem

Thermal Subsystem Performance• All Probes Behave Thermally as Designed• One Exception

– RCS Service Valve on THEMIS E Colder Than on Other Probes

– Protected Against Freezing with Secondary Heater

• Attitude Dependent Thermal Profile– Hot Case: Spin Axis to Sun Angle of 135 deg

(Sun at -45 deg w.r.t. Spin Plane)

Not Yet Seen On Orbit

– Cold Case: Top Deck Towards Sun ± Offset

• S-band Antenna Temperature Too High (> 70 C) When Sun Above Spin Plane by 45-50 deg (Launch Attitude)


Long Term Trend Plots

Long Term Trends of:

• Battery Voltage• Battery Temperature• Tank 1&2 Liquid Temperatures

Probe: THEMIS A

Coverage: 130 Days(100 Orbits − DOY 49−179)

Tank Liquid Temperatures Show Heater Cycles with Periods of 7−8 Days

Battery Voltage

Battery Temperature

Tank 1 & 2 Liquid Temperatures


Telecom Subsystem

Telecom Subsystem Performance• Transponders Work Very Well

– Receivers Are Very Sensitive– Lock on BGS Uplink Signals of Typically 50 W Out to 92,000 km

– Transmitters Work Well– No Problems With Any Modes of Operation– Discovered Direct Modulation Can Be Used at 4K – 64K Data Rates

• Antennas– Seem to Have Lower Gain Than Expected

– Overall Drop by 1.0 dB– Ripple of Up to 4.0 dB pp

• Degraded Telemetry Link Budget– THEMIS B: -3.0 dB

– THEMIS A, C, D: -4.0 dB

– THEMIS E: -5.0 dB


Telecom Subsystem – Cont.

Qual Antenna (AL350) Receive Pattern at 2101.1 MHz (Left) and Transmit Pattern at 2282.5 MHz (Right)

Antenna Was Mounted Over Mock-up Probe Body and Measured at GAAMS Facility (GSFC Code 567)

Contours Are Great Circle Cuts in Azimuth Steps of 5 deg with +Z Axis Pointing to the Right Side


Telecom Subsystem – Cont.

Processed Operational Antenna Patterns

Used to Perform Dynamic Link Margin Predictions and Corresponding Selection of Data Rates for Pass Scheduling


Additional Telecom Issues

Additional Telecom Issues• Problems Encountered on Ground Network Side

– BGS 11m– Supports Passes at Apogee with Data Rates of 64K for THEMIS B

and 32K for All Other Probes Using Direct Carrier Modulation– Improved Station Performance and Procured Additional Receivers– Station Has Best G/T (25.0 dB/K) and Optimal Receiver Performance

– WGS 11m– Station Can Still Not Lock on Telemetry Signal at Current Apogee– Near Perigee Passes at High Data Rates Are Nominal Now– Occasional Problems with Acquisition Vector Processing

– MILA 9m1/2 and AGO 9m– Station Locks on RF and Data at Apogee with 8K and Subcarrier

Modulation– Near Perigee Passes at High Data Rates Are Nominal

– HBK 10m and 12m/6m– Station Works Nominally when Configured Correctly– Used 12m Receive and 6m Transmit Antennas for Most Supports


Updated GN Link Analysis

THEMIS E Downlink to BGS at 512KFrequency 2282.5 MHz

Modulation BPSK

Probe Antenna Gain -7.0 dBic

Probe EIRP -1.3 dBW

Range 21,500 km

Path Loss 186.3 dB

Polarization and Pointing Losses 1.0 dB

Ground Station G/T (BGS) 25.0 dB/K

Data Rate (BSPK) 524.288 kbps

Bandwidth 1048.576 kHz

Coding Gain RS + Rate-1/2 Conv. 8.0 dB

BER 10-6

Required Eb/No 2.5 dB

Predicted Eb/No 7.9 dB

Implementation Loss 2.3 dB

Link Margin 3.1 dB

THEMIS B Downlink to BGS at 4KFrequency 2282.5 MHz

Modulation BPSK


Probe EIRP -2.9 dBW

Range 200,000 km

Path Loss 205.6 dB

Polarization and Pointing Losses 1.0 dB

Ground Station G/T (BGS) 25.0 dB/K

Data Rate (BPSK) 4.096 kbps

Bandwidth 8.192 kHz


BER 10-6




Link Margin 3.2 dB

Updated Ground Network Link Analysis• Takes Into Account Lower Spacecraft Antenna Gains & Ripple• Usage of BPSK with Low Data Rates


SN Link Analysis

TDRSS SSA Return Link at 1KFrequency 2282.5 MHz

Modulation (Mod. Index: 1.6 rad) PCM/PSK/PM


Probe EIRP 2.9 dBW

Range 43,500 km

Path Loss 192.4 dB

Polarization and RFI Loss 0.8 dB

TDRS G/T 10.5 dB/K

Data Rate 1.024 kbps

Channel Power Split Loss 4.9 dB


BER 10-6




Link Margin 9.1 dB

TDRSS SSA Forward LinkFrequency 2101.8 MHz

Modulation (Mod. Index: 1.0 rad) PCM/PSK/PM

TDRS Antenna Gain 37.5 dBic

TDRS EIRP (High-power Mode) 48.5 dBW

Range 43,500 km

Path Loss 191.7 dB

Polarization Loss 0.1 dB

Probe G/T -31.6 dB/K

Data Rate 1.0 kbps

Modulation Loss 4.1 dB

Coding Gain 0.0 dB

BER 10-6

TDRS Transponder Loss 4.4 dB



Link Margin 4.6 dB

Space Network Link Analysis• Originally Performed by GSFC Code 450 – No Change• Available Telemetry Data Rates: 1K, 4K and 8K


RCS and ACS

RCS Performance• Each Probe Carried 48.8 kg of Hydrazine at Launch• Pressurizing Tank with He• Latch Valves and Position Indicators Work Nominally• All Axial and Tangential Thrusters Exercised

(A1 and A2 in Pulsed Mode Only)• Thruster Control Modes Function Nominally• Thruster Temperatures Behave as Expected• No Fuel Leaks Observed – Latch Valves Open Since MD 4• Solenoid and Pyro Valves Not Yet Actuated

ACS Performance• All Sun Sensors and IRUs Function Nominally


Attitude & Delta V Maneuvers

First Attitude Precession and First Delta V Maneuver

Attitude Precession Towards Sun Normal Using Thruster A1

Perigee Raise Maneuver Using Thrusters T1 & T2


Maneuver Summary

Delta V and Propellant Summary

Parameter THEMIS A THEMIS B THEMIS C THEMIS D THEMIS E

Initial Fuel Load [kg] 48.800 48.780 48.810 48.810 48.820

Expended Fuel [kg] 2.046 1.272 2.855 2.464 2.103

Remaining Fuel [kg] 46.754 47.508 45.955 46.346 46.717

Total Delta V [m/s] 26.928 19.944 52.913 48.273 39.000

Total Number of Maneuvers

11 11 19 13 14

Note: Total Delta V includes targeted delta V maneuvers plus contributions imparted by attitude precession and spin rate change maneuvers.


C&DH

C&DH Performance• C&DH Systems Generally Work Well• Encountered Two Anomalies

– THEMIS B:

Generation of Most BAU Housekeeping Packets Stopped on DOY 094

Processor Was Commanded to Perform “Cold Reboot Without Clear” to Restore Proper Functionality on DOY 095

Cause Unknown – Likely Due to SEU

– THEMIS D:

Experienced Cold Restart on DOY 107

FOR Ran Cold Restart Recovery Procedure

No Issues Observed Since

Cause Unknown – Post-event Analysis Failed to Show Cause


BAU FSW

BAU Flight Software Performance• All Probes Currently Use FSW Version 0x3191

– Loaded Into EEPROM Prior to Launch

– FSW Works Very Well in General

• Three Issues Related to Spin Rate Calculation1. Small Increase in Spin Rate Each Time Raw Latched Sun

Pulse Time Rolls Over at Subseconds (Magnitude ~ 0.003 rpm)

2. FSW Skips Processing Interrupts from Sun Crossing Events and Results in a Low Spin Rate Calculation for the Next 5 Averaged Points (Magnitude ~3 rpm at Spin Rate of 20 rpm)

3. FSW Receives Extra Interrupt from Hardware and Resulting in Calculated High Spin Rate (Magnitude ~5 rpm at Spin Rate of 20 rpm)


Instrument Commissioning



Instrument Suite

Instrument SuiteAll Booms Stowed

Deployed Configuration



Instrument Commissioning Activities and Schedule – First Two Weeks On-orbitProbe Activity Description Constraints

A −E IDPU Power On and Checkout

IDPU CMD/TLM links, Power On and Initialize, Go to Normal Mode, Verify IDPU SOH.

Probe Power System Stable and Temp within Operating Limits

A −E FGM Power On and Checkout

Turn on FGM, Go to Standard Mode, Run Functional (Step Function, Find Phase), Dump Quicklook Data

A −E EFI/SCM Power On and Checkout

Turn on EFI Floaters and Boards, Turn on SCM, Run EFI Functional (Noise, AC, DC), Run SCM Calibration, Run EFI/SCM Filters Test, Dump Quicklook Data

A −E Magnetometer Boom Deploy

Turn on Actuator Supply, Enable Deploy (Eng. Mode, Arm), Deploy Mag Boom, Verify Post-deploy Conditions (Spin Rate), Turn Off Actuator Supply

Temp/Voltage Constraints

A −E SST Power On and Checkout

Turn On SST, Run SST Functional (Bias Ramp, Threshold), Open/Close SST Attenuators, Dump Quicklook Data

A −E ESA Cover Open Turn on Actuator Supply, Enable Deploy (Engineering Mode, Arm), Open ESA Cover, Verify Cover Read-back, Turn Off SC Actuator Supply

Temp/Voltage ConstraintsOutgassing > 1 Week

A −E ESA Power On and Checkout

Turn on ESA, Run ESA Functional (Noise, Mask, Pulser), Dump Quicklook Data

A −E ESA High Voltage Ramp Up and Checkout

Enable and Turn On ESA High Voltage, Ramp Up MCP Supply, Ramp Up Sweep Supply, Exercise Sweep at 1/4, 1/2, and Full Scale, Dump IDPU Quicklook Data

Outgassing > 1 Day with ESA Cover Open


Critical Instrument Operations

Critical Instrument OperationsActivity Nominal Operation Verification of Success Risk Mitigation

FGM and SCM Boom Deployment

Simultaneous release of primary FGM and SCM Frangibolts

Verify expected change in spin rate

Redundant frangibolts; Actuation length can be increased

ESA Cover Open Actuation of primary SMA wire for cover release

Verify cover monitor readback Redundant SMAsActuation length can be increased

ESA High Voltage Turn-on

Ramp up Ions/Electrons High Voltage Supplies in 2 real-time passes

Verify expected current readback on MCPs

Real-time scientist feedback on ESA health during ramp-up

EFI SPB Doors Open

Simultaneous release of X pair then Y pair EFI doors

Verify expected actuation current, change in science data

Actuation length can be increased

EFI Spin Plane Boom Deployment

Release of X pair and Y pair wires in 5 m increments

Verify expected motor current, turns count verification, expected change in spin rate

Passive stability with one failed wire boom

EFI Axial Boom Deployment

Release of primary +Z, then –Z AXB frangibolts

Verify expected actuation current, change in science data

Redundant frangibolts (Secondary deploys ±Z AXB simultaneously); Actuation length can be increased


Instrument Performance

Instrument Performance• IDPU

– Flight Software Version 0x46 (THEMIS C) and 0x45 (All Others)

– Nominal Operation and Performance, ETC Kicker Functional

• FGM– Nominal Operation and Performance

• SCM– Nominal Operation and Performance

• ESA– Nominal Operation and Performance

• SST– Nominal Operation and Performance

• EFI– Three EFIs Completely Deployed (THEMIS C, D, E)

– Nominal Operation and Performance


Instrument Requirements Matrix

Probe Bus and Instrument Requirements Matrix

Probe IDProbe Bus

FGM SCM ESA SST EFI

P1 X X (X) (X)

P2 X X O X X (X)

P3 X X O X (X) O

P4 X X O X (X) O

P5 O O O O (O) O

X = Function Required for Minimum Mission (1 Year, 94 h of P1-P4 Conjunctions in One Tail Season)

O = Additional Function Required for Baseline Mission (2 Years, 188 h of P1-P4 Conjunctions per Tail Season, Including 94 h of P1-P5 Conjunctions per Tail Season)

() = Only Partial Function Required (1 SST Head, 1 Pair of EFI Spin-plane Booms)


Probe Placement Decision

Probe Placement Decision• Assigned Constellation IDs (P1−P5) to Probe Buses

THEMIS A −> P5THEMIS B −> P1THEMIS C −> P2THEMIS D −> P3THEMIS E −> P4

• Decision Based on Probe Bus and Instrument Performance– Also Included Performance Details Found During Ground Testing

– Only Differences Noted Are in Telecom System• Team Members Involved in Probe Placement Decision

– PI, PM, MSE, MOM, MDL, Swales Probe Bus Systems Lead, Instrument Scientists, GSFC Program Manager and GSFC Project Scientist

• Coast Phase Orbit Set-up (THEMIS A−E) Interleaved with EFI Deploy (THEMIS C−E) Followed Probe Placement Decision


Probe Identification Matrix

THEMIS Probe Identification Matrix

Probe Bus / Simulator

Name

Probe Bus ID

Instrument Suite ID

CCSDS V1 TLM/CMD

SCID

NASA Support ID Code

UCB Satellite Catalog Number

NORAD Satellite Catalog Number

International Designator

Constellation ID

FlatSat West — — 0x150 — — — — —

THEMIS A F1 FM1 0x153 0451 99001 30580 2007-004A P5

THEMIS B F2 FM2 0x151 0452 99002 30581 2007-004B P1

THEMIS C F3 FM3 0x155 0453 99003 30582 2007-004C P2

THEMIS D F4 FM4 0x154 0454 99004 30797 2007-004D P3

THEMIS E F5 FM5 0x152 0455 99005 30798 2007-004E P4

THEMIS Spare — — 0x156 — — — — —

FlatSat East — — 0x157 — — — — —


EFI Deployment

EFI Deployment• THEMIS C (P2) Was Trail Blazer

– 13 Deployment Steps Plus Initial Spin-up to 20 rpm– Fortunately No Restrictions on Transmitter-on Times

– Four Sets of Alternating Operations– Wire Boom Spool-out on X and Y Axes in 5-m Steps– Spin-up Maneuvers– Sensor Diagnostic Tests

– Last Step Is Release of +Z and −Z Axial Booms

– All Completed in 7 Working Days

• THEMIS D (P3) & E (P4) Followed 3 Weeks Later– Performed Interleaved with Back-to-back Operations

– Optimized On-console Staffing– Instrument and Mechanical Engineers for Boom Deploy Operations– Propulsion and Flight Dynamics Teams for Spin-up Operations

– All Completed in 5 Working Days


EFI Deployment

THEMIS C EFI Deploy Steps 3 & 6 Using Dual Pulse Thrusting of T1

First Spin-up with Wire Booms Out by 5m in X and Y

Unfurling of Fine Wires in X and Y

Spin-up to 15 rpm Spin-up to 26 rpm


Coast Phase

Coast Phase


Coast Phase Operations

Coast Phase Operations• Purpose of Coast Phase

– Additional Mission Phase Inserted to Control Orbital Dispersions Prior to Mission Orbit Placement in Fall of 2007

– Dayside Science Campaign

• Instrument Characterization and Tuning– SST Attenuator Operations

– EFI Bias Currents, Usher and Guard Voltages, Sensor Diagnostic Tests (SDTs)

• Science Data Acquisition– Tuning of Science Trigger Algorithms

– Usage of Predicted Magnetospheric Regions of Interest

– Optimization of Acquisition and Recovery of Science Data Volumes

• Orbit Placement for Coast Phase– See Mission Design Presentation


Coast Phase Orbit Placement

Intermediate Orbits Towards Coast Phase Alignment


Ground Systems Performance

Ground Systems Performance


Ground System Block Diagram

Ground System Elements•Ground Stations

•Space Network

•Mission Operations Center

•Science Operations Center

•Flight Dynamics Center

Interfaces•Secure Real-time TCP/IP

Socket Connections

•File Transfer via Secure Network and Open Internet


Ground Systems Status

Ground Systems Status• Mission Operations Center

– All Hardware and Software Systems Performed Essentially Flawlessly Since Prior to Launch

• Flight Dynamics Center– Two-way Doppler Tracking Data Processed by GTDS for OD

– Attitude Determination via MSASS

– Integrated Mission Design Tool and GMAN Work Well

• Berkeley Ground Station– Supported Almost 900 Pass with THEMIS Probes

– Receiver Upgrade in Progress to Improve Data Recovery

• IT Network Systems– Servers and Workstations Work Nominally

– T1 Line to GSFC Had No Issues Since Launch

– Dial-up IDSN Line to HBK Works Well


Telemetry Recovery Plan




Telemetry Recovery Plan• Instrument Data

– Each Probe Accumulates Up to 750 Mbits of Instrument Data per Orbit– Data Compressed by Factor of 1.5-2.0 Prior to Transmission to the Ground– Apply 12% Overhead for CCSDS Formatting, 14% for RS Code Symbols, 5% for Replay – Resulting Science Telemetry Data Volume Is 503-670 Mbits / Orbit / Probe– Required Downlink Time 16-22 min Orbit / Probe at Data Rate of 524.288 kbps

• Engineering Data– Each Probe Bus Accumulates Up to 87 Mbits of Engineering Data per Orbit– Apply 12% Overhead for CCSDS Formatting, 14% for RS Code Symbols, 5% for Replay– Resulting Engineering Telemetry Data Volume Is 111 Mbits / Orbit / Probe– Required Downlink Time 4 min / Orbit / Probe at Data Rate of 524.288 kbps

• Ground Stations– Primary Ground Station (BGS) Supports 1360 Passes / Year for Telemetry Recovery

(Original Plan)– Secondary Ground Stations (WGS, MILA, AGO and HBK) Support 190 Passes / Year

Combined for Telemetry Recovery– Additional Tracking Passes Scheduled for Special Operations and Probe Monitoring– Additional Stations Are Considered to Fill Coverage Gaps (USNAU 13m), to Alleviate

Scheduling Conflicts (USNHI 13m) and to Provide Long Range Coverage (White Sands)


Probe Science Data Acquisition

Probe Science Data Acquisition• Science Mode Selected by ATS and / or On-board Triggers

– Slow Survey (SS)– Fast Survey (FS)– Particle Burst (PB)– Wave Burst (WB)

On-board Data Compression• Selectively Enabled / Disabled

– Huffman, Delta Modulation, Decimation– Applied Prior to Downlink

• Compression Factor of 2.0 Seems to Be Achievable– Efficiency Depends on Instrument Data Type

• Solid-state Recorder Sized at 256 MBytes– 100 MBytes Available for Storage of Science Data


Data Quality Metrics

Data Quality Metrics• Conjunction Science

– Tail and Dayside Seasons Nominally Defined as WD ± 2 Months– Tail Season 1 (T1) Winter of 2006/2007 (Skipped)– Day Season 1 (D1) Summer of 2007– Tail Season 2 (T2) Winter of 2007/2008– Day Season 2 (D2) Summer of 2008

– 750 Mbits Uncompressed per Orbit per Probe Corresponds to 100%• Radiation Belt Crossings

– Slow Survey Mode – Secondary Science Goal– 40 Mbits Uncompressed per Orbit per Probe Corresponds to 100%

• Engineering Data– Recorded Throughout Orbit at Various Cadences– Total Recorded Data Volume Corresponds to 100%

• Statistics Generated Against Above Metrics– Recovery Requirement for All Science and Engineering Data Is 95%– Included in Weekly Status Reports to SSMO Project Office


Anomalies

Anomalies


Anomaly Resolution

Flight & Ground Systems Anomaly Resolution• Tiger Teams Assigned

– Investigate Cause of Anomaly

– Recommend Solutions, Work-arounds and/or Mitigations

• Anomaly Tracking List– Items Closed Out When Anomaly Report Written and

Recommended Actions Were Performed

– Currently Tracking 11 Items (9 Closed Already)


Anomaly Tracking List

Anomaly Tracking ListID Date Anomaly Title Description and Status of Anomaly Closure

1 2/20/2007 Weak Signals with Space-to-ground Communications

Telemetry signals on all five probes appear to be appreciably weaker than predicted prior to launch. Mitigations are currently developed and tested.Affected probes: All

NET 6/30/2007

2 2/18/2007 False Over-voltage Protection Trips

False over-voltage protection trips occur when the battery is fully charged, and are apparently caused by transients when the transmitter is configured and/or turned on/off via relays inside the transponder. Operational work-arounds are in place.Affected probes: All

NET 6/30/2007

3 2/18/2007 Potential Over-charge of the Battery

Solar panels generate appreciably more power than expected, and the power control system cannot dissipate excess power at certain attitudes. As mitigation, additional loads are turned on (catalyst bed heaters and IRUs) to dissipate power as necessary. As additional protection, new tables with improved limit monitors will be uploaded to EEPROM.Affected probes: All

Closed4/6/2007

4 2/28/2007 Spin Rate Drop or Rise Occasional errors in the on-board spin rate calculations were observed on all probes and occur on average a few times per day. The spin rate drops were reproduced on FlatSat and a FSW patch was developed. Operational work-arounds are in place. The spin rate rises are under investigation.Affected probes: All (Spin rate rise seen only once on THEMIS C)

Closed 6/28/2007

5 3/8/2007 Corrupted Level Zero Science Data Processing

Ground processing software did not correctly process packets spanning frame boundaries when frames were missing. The software was fixed and all science data were successfully reprocessed.Affected probes: None

Closed3/20/2007


Anomaly Tracking List – Cont.

Anomaly Tracking List - ContinuedID Date Anomaly Title Description and Status of Anomaly Closure

6 3/14/2007 Instrument ETC Packet Generation Halted

Every few weeks the packet data generation from the ESA and SST instruments that is controlled via the ETC FPGA halts. A FSW patch was developed to detect these conditions on orbit and to restart the packet data acquisition. Tests on FlatSat are ongoing.Affected probes: Likely all, except that problem has not been seen on THEMIS E.

Closed 6/14/2007

7 3/26/2007 Instrument ETC Table Loads Unreliable

Problem is caused by conflicting processes accessing ETC memory while tables are loaded from IDPU EEPROM to this memory. Work-around successfully tested on FlatSat.Affected probes: All

Closed 4/27/2007

8 4/1/2007 IDPU Data Compression IDPU resets and instrument turn-off occurred on three probes shortly after science data compression was started. IDPU FSW patch version 0x45 uploaded to all probes.Affected probes: Likely all, although compression was only used on three probes, and these experienced the resets (THEMIS A, B and D).

Closed 6/14/2007

9 4/4/2007 BAU PCM Packet Generation Halted

Generation of BAU power and thermal engineering packets read from the PCM card halted. Resetting the PCM card and warm resetting the BAU did not restore operational status. Cold reset without clear did restore the packet generation. Likely cause was a Single Event Upset (SEU). A report is currently written.Affected probes: Seen only once on THEMIS B.

Closed 6/28/2007

10 4/5/2007 BAU Generates Inaccurate Sun Pulse Time Stamps

BAU generates time tags for sun pulses that are occasionally off by a few milliseconds. Possible work-around is to fix the time stamps in ground processing.Affected probes: All

Closed 6/14/2007


Anomaly Tracking List – Cont.

Anomaly Tracking List - ContinuedID Date Anomaly Title Description and Status of Anomaly Closure

11 4/17/2007 BAU Experienced Cold Reset

A cold reset was experienced without any recognizable cause. As a result of the reset, the IDPU and instruments were turned off. BAU mode logs were downloaded and are currently analyzed.Affected probes: Seen only once on THEMIS D.

Closed 6/28/2007


Known Instrument Issues

Instrument Issues Known Prior to Launch

PFR #Probe /

InstrumentIssue Operational Work-Around

PFR 030 All ProbesActuators

PCB FPGA accepts actuator commands only if actuator voltage is present. If SC actuator supply trips off during actuation, PCB will not turn off actuator switch. Thus, actuator will be active when actuator supply voltage is re-enabled.

In the event that the SC Actuator supply trips off during an actuation, the ground must enter a SAFE command prior to re-enabling supply. (SAFE command has IPCB_ACTREST which resets all instruments and states).

PFR 075 All ProbesESA

ESA High Voltage tripped off during Suite Thermal Vacuum testing due to in-rush.

PCB supplies must be forced on during Low Voltage, High Voltage and HV level adjustment. Current trip should be re-enabled after during normal operations.

PFR 164 All ProbesESA

Unloaded ESA supply causes IDPU current oscillation at narrow temperature range around 10 C.

Oscillation would only be seen if ESA was off over narrow temperature range. FOT alerted that condition can be expected and causes no damage.

PFR 183 Probe CEFI

Lower AXB (V6) EFI channel responded anomalously during EFI Functional Test (DC excitation higher amplitude and noisier, AC excitation high-pass filtered).

Not an issue after AXB deploy. Unit still provides sufficient SOH (through anomalous, but consistent DC response) information to make probe assignment decision.

PFR 206 Probe DEFI

F4 AXB temperature sensor reads incorrectly (1052 C). Performance of associated EFI channel not affected.

Temp sensor not critical for operation of the EFI. Failed state of the F4 AXB temp sensor noted by FOT to avoid alarm over condition.


Constellation Status Summary




Constellation Status Summary• Mission Completed 100 Orbits on Mission Day 130 (Today)• All Five Probes Are Very Healthy• Orbits and Attitudes Are Stable and Safe• Subsystems Performance Nominal• All Instruments Are Powered On and Function Nominally• EFI Booms Are Completely Deployed on THEMIS C, D and E• Ground Systems Are Functioning Well• Flight Dynamics Operations Are Almost Routine• Operations Team Has Everything Under Control• Constellation Status Online and Updated with Each Pass

http://soleil.ssl.berkeley.edu/ground_systems/themis_constellation_status.html

• Planning Schedule Available Onlinehttp://soleil.ssl.berkeley.edu/ground_systems/request_planning.themis.txt


Constellation Status Page


Critical Operations

Completed Critical Operations• RCS Operations

– Completed 68 Thrust Maneuvers for Orbit and Attitude Control– Fired All Thrusters (A1 and A2 in Pulsed Mode Only)

• Instrument Operations– Magnetometer Booms Deployed on All Probes– EFI Boom Deployment Completed on THEMIS C (P2), D (P3) & E (P4)– ESA Covers Are Open and HV Turned On

Remaining Critical Operations• Mission Orbit Placement

– Beginning in September and Completed in December 2007

• Fuel Tank Repressurization– Need to Expend Fuel Mass – Min and Max Limits Driven by RCS System– Required Tank Pressure Range 75 – 400 psia – Repressurization Will Be Interspersed with Mission Orbit Placement

• EFI Boom Deployment– THEMIS B (P1) and THEMIS A (P5)– Following Mission Orbit Placement


Configuration Management

Configuration Management• Application of Configuration Management

– Workspaces– Operational Software & Databases– Configuration Files– Hardware Configurations– Network Configurations– Procedure Documents

• Configuration Freezes– Current Status: Soft Freeze– Regression Testing Completed– Changes Allowed for Software and Hardware Upgrades– Prior Approval Required by Local CCB:

PM (as required), MOM, DMOM, MSE (as required), ITM (as required)

• Instrument Configuration Change Requests– Approved by PI, Tohban, MSE, Instrument Scientist, ISE, MOM


Staffing & Engineering Support

Staffing & Engineering Support• Flight Operations

– All Flight Procedures Executed by Certified Flight Controllers– All Special Operations Require Presence of Cognizant

Subsystems Engineers and/or Instrument Scientists On Console at MOC or via Remote ITOS Displays

– RCS Operations (Commissioning, Maneuvers, Pyro Valve Opening)– Instrument Commissioning & Configuration, Boom Deployment

• FlatSat Testing– Performed by FOT, Flight Dynamics Team, Instrument Team

– All STOL Procs Tested and Verified on FlatSat

– All Maneuvers Simulated on FlatSat/VirtualSat

• Sustaining Engineering– UCB Subsystems Engineers

– Available and Called as Needed

– Spacecraft Bus and FSW Subsystems Engineers– Contracts for Field Support


Back-up Slides

Back-up Slides


Updated Flight Rules

Updated Flight Rules


Power System Flight RulesPower System Flight Rules

Activity Flight RulePotential Impact of

ViolationAction to Prevent

Violation

Subsystem power-on Subsystems must be powered on only when their temperatures are within ITOS green limits.

Damage to flight hardware.

Monitor subsystem temperatures.

Load shedding Bus voltage must be kept within ITOS green limits.

Load shedding will occur autonomously on-board when under-voltage condition is detected.

Battery state-of-charge too low.

Power down of instrument bus and/or selected probe bus components.

Monitor battery state-of-charge and overall power budget.


Telecom Flight RulesTelecom Flight Rules



Violation

Transmitter operation

Transmitter on-time limited by transmitter temperature staying within ITOS green limits.

For nominal science operations planning and analyses, transmitter on-time is limited to 60 min per day.

Overheating of transmitter and damage of power amplifier.

Set on-board FDC parameter to turn off transmitter after 60 min.

Monitor transmitter-on time on the ground and alert FOT to turn off transmitter.

Schedule passes and build ATS loads with transmitter-on times of 60 min or less.


Minimum transmitter off-time of 3 hours between transmitter on-times is required only if transmitter reached maximum allowable temperature during pass.

Current thermal analyses show that transmitter needs to be off for 3 hours to cool down completely from maximum temp.

Overheating of transmitter and damage of power amplifier.

Monitor transmitter temperature.

Schedule passes and build ATS loads with transmitter-on times of 60 min or less.


Telecom Flight Rules – Cont.Telecom Flight Rules



Violation


Minimum period of transmitter off-time prior to entry and after exit of long shadows.

Exact times are driven by operational activities and overall power management.


Include check for long shadow periods in pass planning activities.


Transmitter on-time during shadows limited to less than 30 min.

Allowed transmitter-on times for a given shadow period are driven by overall power management.


Include check for shadow constraints in pass planning activities.


No transmission during launch vehicle thrust phases.

Damage to probe transmitter due to corona effects.

Check LV ascent profile. Embed checks into ascent procs and procedures.


Cycle transmitter power using FET in power module only while leaving transmitter-on relay always in on-position.

Excessive wear of relay contacts with potential for inability to turn transmitter on.

Configure blind acquisition procs and RTS loads to turn relay and FET on (in this order), but only FET off.


RCS Flight RulesRCS Flight Rules



Violation

Thruster operation Catalyst bed heaters must be turned on 30 min (nominal) or 20 min (contingency) before thrusting to heat up, and are turned off at the end of thrusting.

Damage to catalyst beds.

Verify catalyst bed current prior to enabling thrust sequence.

Thruster firing Thrusters must not be fired unless ESA HV is ramped down and SST attenuators are closed.

Damage to ESA and/or SST.

Verify HV and SST attenuator status prior to maneuver execution.

Thruster firing Maneuvers must not be performed in shadow.

Erroneous maneuver execution.

Check shadow constraints as part of maneuver planning.

Tangential thruster firing

Tangential thruster T1 (spin-up thruster) must not be fired until SCM boom is deployed.

Damage to SCM sensor by thruster plume.

Include deployment check in early maneuver sequences.

Pyro valve operation Before re-pressurization, thrusters shall be fired only when the pressure in the propellant tank is 75 psia or higher.

Operation outside qualification pressure limits.

Verify tank pressure in valve operations procedure.

Pyro valve operation The pyro valve shall not be opened until enough fuel is consumed so that the fuel tank pressure will be 400 psia or less at any expected temperature in the re-pressurized state.

Bursting of fuel tanks. Destruction of probe.

Verify tank pressure in valve operations procedure.


RCS Flight Rules – Cont.RCS Flight Rules Continued



Violation

Pyro/Isolation valve operation

Pyro valve must be opened only when isolation solenoid valve is open.

Isolation valve cannot be opened against high pressure differential. Partial loss of mission.

Verify isolation valve open status in pyro actuation procedure.

Pyro/Isolation valve operation

After pyro is blown, isolation valve must be opened 3 min later.

Isolation valve cannot be opened against high pressure differential.

Verify isolation valve operation in pyro actuation procedure.

Isolation Valve operation

Isolation valve shall not be held open more than 4 min at any time.

Temperature exceedance.

Include checks in flight procedures and procs that controls isolation valve.

Load shedding Two of three RCS heater services shall be on at all times.

Freezing and bursting of fuel lines.

Include checks in flight procedures and procs that control heaters.

Load shedding RCS heater service #2 shall never be turned off.

Freezing and bursting of fuel lines.

Include checks in flight procedures and procs that control heaters.


RCS Flight Rules – Cont.RCS Flight Rules Continued



Violation

Pulsed thruster firing Pulsed operation of thrusters must not be performed at pulse rates at or near natural predicted frequencies of nutation, spin-plane booms, axial booms and propellant slosh.

Loss of dynamic stability.

Keep pulse durations short to avoid resonance frequencies.

Pulsed thruster firing The thruster pulse repetition rate shall be synchronized at once per probe rotation.


Dynamics review of pulse thrusting proc.

Axial pulsed thruster firing

The preferred pulse half width for axial thrusting is 12 degrees for all tank levels.

Excessive near resonant slosh.


Side pulsed thruster firing

The preferred pulse half width for side thrusting is 30deg unless tank fill is between 68% and 58% or 39% and 29% where half width should be reduced to 20deg.

Excessive near resonant slosh.


Pulsed thruster firing Pulsed side and axial thrusting shall not be combined.



Thruster firing A Critical Stop command shall be sent prior to issuing any thrust commands.

Improper maneuver execution.

Include checks in flight procedures and procs that control thruster operations.


ACS Flight RulesACS Flight Rules



Violation

Spin rate control Spin rate must be maintained within range of 5-26 rpm.

Loss of dynamic stability. Damage to booms.

Monitor spin rate and set into safe regime prior to boom deployment.

Monitor spin rate during side thrusting maneuvers.

Attitude control Probe attitude (spin axis) must be maintained such that the Sun is kept out of the exclusion zone of 15 deg with respect to the surface normal of the top and bottom decks.

Thermal problems with probe bus in general and deployed axial booms in particular.

Monitor attitude and take flight rule into account for planning attitude precession maneuvers.


FSW / C&DH Flight RulesFSW / C&DH Flight Rules



Violation

RTS operation No combination of ATS, RTS, and real-time commands shall be sent to exceed the maximum command rate per task as stated in the FSW Users Guide.

Erroneous command execution.

Configuration control of FDC. Verify ATS loads and check for violations.

Clock adjustment Clock adjustments must not be performed during critical operations such as maneuvers.

Erroneous maneuver execution.

Place verification steps into procs that execute clock adjust.

Clock adjustment Do not command large clock jumps during RTS execution.

Commands skipped over will execute.

Place verification steps into procs that execute clock adjust.


Instrument Flight Rules

Instrument Flight Rules



Violation

IDPU power-on IDPU temperature must be within allowed operational limits prior to powering up

Unclean start-up likely Verify IDPU temperature in procedure

EFI power-on EFI Floater voltages must be powered on prior to (~10 s) to EFI Board

Prevents EFI BIAS drivers from latching at a ±100 V rail

EFI_ON.proc with correct sequence used whenever EFI is powered on

ESA HV power-on ESA HV must not be turned on until initial outgassing is completed

Damage to ESA Disable HV turn-on procedure until L+7 days

ESA HV power-on ESA HV must not be turned on until at least 60 min after a thrust maneuver is completed

Damage to ESA Verify time since last maneuver in HV turn-on procedure

ESA HV ramp-down ESA HV must be ramped down prior to thruster operation

Contamination of ESA Check status prior to enabling Prop Bus for maneuver

SST attenuator operation

SST attenuators must be closed prior to thruster operation

Possible performance degradation (calibration change)

Check status prior to enabling Prop Bus for maneuver


Instrument Flight Rules – Cont.

Instrument Flight Rules − Continued



Violation

Boom deployment All booms must be deployed only when their temperature is within the allowed range.

Minimum deployment temperature for magnetometer booms is -17 C. Probe attitude may have to be adjusted to bring temperature into allowed range.

Unsuccessful boom deployment; Overheating of boom frangibolts causing contamination

Include temperature/ voltage check in procedure

Magnetometer boom deployment

Magnetometer booms must be deployed at spin rates from 2 to 12 rpm.

Unsuccessful boom deployment; Damage to magnetometer booms

Include spin rate checks in deployment procedure

EFI radial boom deployment

EFI radial booms must be deployed at spin rates detailed in SPB Boom Deploy.xls spreadsheet.

(Too High) Damage to boom deployment mechanism at high cable root tension; (Too low) Excessive spin down

Include spin rate check in deployment procedure; Predict cable root tension for deployments

EFI axial boom deployment

EFI axial booms must not be deployed unless spin-plane booms are deployed to their nominal distance.

Loss of dynamic stability

Verify spin-plane boom deployment status in procedure

THEMIS RRConstellation Operations − 1UCB, June 28, 2007 THEMIS Constellation Operations Manfred...

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