THEMIS Mission Operations Peer Review Mission Operations − 1UCB, November 4, 2003
THEMIS Mission Operations
Manfred BesterTHEMIS Mission Operations Manager
THEMIS Mission Operations Peer Review Mission Operations − 2UCB, November 4, 2003
Mission Operations
Overview− Mission Operations Concept− Ground System Requirements− Lessons Learned− Ground System Design− Mission Operations Center− Software Tools− Berkeley Ground Station− Mission Operations− Staffing− Telemetry Recovery− NTIA License− IT Security
THEMIS Mission Operations Peer Review Mission Operations − 3UCB, November 4, 2003
Mission Operations Concept
Space Segment− 5 Spinning Probes in High Earth Orbits− Simultaneous Release from LV− Initial Orbits Close to Nominal Mission Orbits of Probes 3 and 4− Probes 1, 2 and 5 Move to Nominal Mission Orbits Prior to First Tail Season− Store and Forward Strategy for Science Data Recovery− All Probes Share Same Frequency − Contact One Probe at a Time
Ground Stations− Berkeley Ground Station as Prime Facility− Wallops GN or Universal Space Network as Secondary− TDRSS SSA for Ascent, Maneuver and Contingency Support
Operations Centers− Mission and Science Operations Centers Co-located at U.C. Berkeley
THEMIS Mission Operations Peer Review Mission Operations − 4UCB, November 4, 2003
Ground System Requirements
Requirements for the THEMIS Ground System− Support of Simultaneous Mission and Science Operations for 5 Probes− Complete Flight Dynamics Support Including Maneuver Planning− Automated Pass Scheduling Functions− Secure Network Links to Local and Remote Ground Stations− Completely Isolated Network Link for TDRSS Support− Real-time Command and Control Functions− Generation of Command Loads− Databases for Probe Configuration & Status and Telemetry History− Web Based Tools for Probe Status Displays and Trend Plots− Detection of Limit Violations and Anomalies− Emergency Notification via Pagers and Email
THEMIS Mission Operations Peer Review Mission Operations − 5UCB, November 4, 2003
Lessons Learned
Lessons Learned from Previous Berkeley Missions− EUVE, FAST, RHESSI, CHIPS
Lessons Learned from Existing Constellation Missions− Globalstar− Iridium− Cluster− Consult with Operations Personnel− Find Out How Other Constellation Missions Operate− Consult with Scientists Working with Cluster Data
Take Advantage of Ideas and Concepts and Lessons Learned− THEMIS Ground System Design− THEMIS Mission and Science Operations
THEMIS Mission Operations Peer Review Mission Operations − 6UCB, November 4, 2003
Constellation Operations
Questions for Globalstar / Iridium / Cluster Operations Personnel− How are operations of a satellite constellation organized?− How many engineers and other support staff are required and what are their team roles?− Which software tools are used operationally?− What types of databases are used and what are their benefits and shortfalls?− How are individual spacecraft monitored and commanded?− How are operational status and configuration of each spacecraft maintained?− How are ground images of the flight software organized?− How is the overall constellation organized and maintained?− How are orbit maneuvers planned and executed?− Are spacecraft grouped operationally, e.g. by functions or by orbit plane or otherwise?− How are data flows organized?− How are individual spacecraft distinguished for telemetry and commanding?− Which spacecraft designators are used and how are they used?− What types of communications are used between control centers and ground stations?− Which operations functions are automated and to what extent?− How are anomalies reported and tracked?− How are contingencies handled?− What is planned for end-of-life operations?− What pitfalls or sources of confusion were encountered and how should they be avoided?− What lessons were learned and what should be done differently?
THEMIS Mission Operations Peer Review Mission Operations − 7UCB, November 4, 2003
Globalstar Lessons Learned
Globalstar Lessons Learned− Test Each Spacecraft Carefully Before Launch
− Assembly Line Approach Led to Multiple Wrongly Wired Magnetometers− Test Flight Software Patches Carefully Prior to Uplink
− Assembly Line Approach Caused Multiple Spacecraft to Lose Attitude Control Before Automated Uplink Process Could Be Stopped
− Employ Modern Automation Techniques− Save Operations Costs and Enhance Reliability
− Provide Diagnostic Tools− Flexible Tools Allow Engineers and Scientists to Compare Trends Between Different
Spacecraft− Some Great Engineering Ideas Turned Out to NOT Be Useful
− Plan for Contingencies on Routine Basis in Daily Pass Schedules− Plot Trends for Multiple Spacecraft on Top of Each Other− Allow Operators to Set Their Own Limits− Sophisticated Database to Track Anomalies Across Satellites
THEMIS Mission Operations Peer Review Mission Operations − 8UCB, November 4, 2003
Operations Org Chart
All Aspects of THEMIS Operations Are Performed at UCB / SSL NASA / GSFC GNCD Provides Support in Form of Consulting
THEMIS Mission Operations Peer Review Mission Operations − 9UCB, November 4, 2003
Ground System Block Diagram
THEMIS Mission Operations Peer Review Mission Operations − 10UCB, November 4, 2003
MOC Expansion
Expanded 900 ft2 MOC Facility at SSL
THEMIS Mission Operations Peer Review Mission Operations − 11UCB, November 4, 2003
Mission Operations Center
BGS Antenna, Equipment Racks and FOT Workstations at the Mission Operations Center
THEMIS Mission Operations Peer Review Mission Operations − 12UCB, November 4, 2003
Overview of Software Tools
Tool Developer Function Platform Comments
GTDS GSFC Ephemeris Generation, Orbit Determination
Solaris In Operation at MOC Already
GMAN GSFC Maneuver Planning Solaris, Linux In Operation at MOC Already
MSASS GSFC Attitude Determination Windows In Operation at MOC Already
SatTrack BTS Orbit Analysis, Pass Scheduling, Networking, Visualization
Solaris, Linux In Operation at MOC Already
ITOS Hammers Probe Command and Control Solaris, Linux In Operation at MOC Already
MPS GSFC Command Load Generation Solaris In Operation at MOC Already
BEARS UCB Emergency Response System Solaris, Linux Under Development at SSL
APGEN JPL Task and Event Scheduling Solaris In Operation at MOC Already
GMSEC GSFC Data Mining & Paging Solaris Option to Be Investigated
TAPS GSFC Trend Analysis Solaris (?) Option To Be Investigated
TeamTrack TeamShare Anomaly Tracking Windows Option To Be Investigated
THEMIS Mission Operations Peer Review Mission Operations − 13UCB, November 4, 2003
Operational Databases
Probe Configuration and Status Database− Relational Database− Complete State-of-health History in Raw Telemetry Units for Each Probe− Complete Probe Configuration History (Tables, ATS Loads, FSW Versions)− Support of Trend and Command History Analysis
Pass Scheduling Database− SatTrack Provides Automated Pass Scheduling Functions− Ingests Confirmed Schedules of Remote Facilities (NASA/GN, USN, Others)
Interfaces Between Databases− Scheduling System Needs to Know Various Probe Status Parameters
THEMIS Mission Operations Peer Review Mission Operations − 14UCB, November 4, 2003
Probe Identification
Type of Probe IDAssigned
ByPurpose
Assignment Type
Location Where Stored at MOC
Location Where Stored on Probe
CCSDS V1 Command SCID
(e.g. 0x151)
WDC-A-R&S
Command Verification
Permanent With Probe Bus
Probe Specific ITOS & MPS Configuration
Probe Uplink Card(Jumpers)
CCSDS V1 Telemetry SCID
(e.g. 0x151)
WDC-A-R&S
TelemetryVerification
Permanent With Probe Bus
Probe Specific ITOS Configuration &
Ground Station FEPs
Probe BAU EPROM
Satellite Catalog Number(e.g. 29501, Assigned
after launch)NORAD
Identification of Orbital Elements
Permanent With Probe Bus
Flight Dynamics Object Database N/A
International Designator(e.g. 2006-001A,
Assigned after launch)
COSPAR/ WWAS & NORAD
International Reference
Permanent With Probe Bus
Flight Dynamics Object Database N/A
Probe Bus Name(e.g. THEMIS 1 and
Red Probe)UCB Constellation
ManagementPermanent With
Probe BusGround System
Database N/A
Constellation Designator(e.g. P1) UCB Constellation
Management
Dependent on Probe
Assignment in Constellation
Ground System Database N/A
THEMIS Mission Operations Peer Review Mission Operations − 15UCB, November 4, 2003
Probe Identification Matrix
Probe Bus Name CCSDS V1 Command SCID
CCSDS V1 Telemetry SCID
Satellite Catalog Number
International Designator
Constellation Designator
THEMIS 1Red Probe 0x151 0x151 29501 2006-001A P1
THEMIS 2Yellow Probe 0x152 0x152 29502 2006-001B P2
THEMIS 3Green Probe 0x153 0x153 29503 2006-001C P3
THEMIS 4Blue Probe 0x154 0x154 29504 2006-001D P4
THEMIS 5Purple Probe 0x155 0x155 29505 2006-001E P5
THEMIS SIMWhite Probe 0x156 0x156 N/A N/A Simulator
Note: Only the Constellation Designator in the last column will change as a result of a probe replacement.
THEMIS Mission Operations Peer Review Mission Operations − 16UCB, November 4, 2003
Usage of Probe Identifiers
Telemetry File Naming ConventionsFormat:− FACILITY.PROBE_BUS_NAME.TLM_VCN.YYYY_DDD_HHMMSS.datExamples:− BGS.THEMIS_1.TLM_VC0.2007_028_060312.dat− BGS.THEMIS_1.TLM_VC1.2007_028_060312.dat− BGS.THEMIS_1.TLM_VC2.2007_028_060312.dat− BGS.THEMIS_1.TLM_VC3.2007_028_060312.dat
THEMIS Mission Operations Peer Review Mission Operations − 17UCB, November 4, 2003
ITOS Requirements
General ITOS Requirements− Same as with FAST and RHESSI (See ITOS Standard Documentation)
Performance Improvements− Configuration Monitors Built Into ITOS
Implementation of New Features− Collected Suggestions from Flight Controllers and Other Missions− New Desirable Features for Constellation Operations
− Batch Mode for Telemetry Processing (May Be Possible Already Via Scripting)− Telemetry Server for Distribution of Data Streams to Multiple ITOS Clients− Joined Status Displays for Multiple Probes
− New Features Hammers Is Planning to Incorporate− Arrays of Mnemonics (1-D or 2-D)− Event Displays
THEMIS Mission Operations Peer Review Mission Operations − 18UCB, November 4, 2003
ITOS Configuration
Dedicated Workstations− Basic Configuration Is One Dedicated ITOS System per Probe− Additional Flexibility Built Into System for Dynamic Allocation of Workstations − TLM/CMD Connections Initiated from ITOS to Ground Station Supporting Probe− Multiple Backup Systems
Future Options for System Automation− Envision Upgrade Path Towards More Complex Future Missions− ITOS Connects to SatTrack Gateway Server (SGS)− ITOS Specifies Mission (e.g. THEMIS) and Leaves Individual Object and Facility
Unspecified− SGS Assigns Individual ITOS System to a Particular Pass Support− Routing of Telemetry and Command Connections Via FrameLink or Netcat− ITOS in Turn Loads TLM/CMD Databases and Procs and Supports Pass
THEMIS Mission Operations Peer Review Mission Operations − 19UCB, November 4, 2003
ITOS Page Layout
Rules for ITOS Telemetry and Status Page Layout− Uniform Page Header
− Probe Identifier with Unique Color Coding− UNIX System Time− Probe System Time
− Uniform Page Layout (Sub-headers, Data Columns, Grouping of Parameters)− Usage of SI Units Only (V, A, s, m, kg, G, N, …)− Assigned Button Colors for Particular Functions− Usage of Templates− Incorporate Feedback from Flight Controllers
THEMIS Mission Operations Peer Review Mission Operations − 20UCB, November 4, 2003
Sample ITOS Page
Standard Features:− Color Coding for Probe
Identification− UTC and Spacecraft Clocks− Telemetry Update Status− Unified Color Scheme− Color Coding for Green,
Yellow and Red Limits− Button Control to Start
Additional Pages− Button Control to Start
Configuration Monitors
THEMIS Mission Operations Peer Review Mission Operations − 21UCB, November 4, 2003
TLM & CMD Naming Conventions
Rules for Telemetry & Command Naming in ITOS Database− Identify Subsystems in Telemetry Mnemonics and Commands− Use CLEAR Commands Only to Clear Counters or Status Flags− Use RESET Commands Only to Power Cycle or Reboot Subsystems
THEMIS Mission Operations Peer Review Mission Operations − 22UCB, November 4, 2003
Mission Control Network
Network Architecture
All Ground Stations Connect to Different Ports on IP Router to Establish TLM and CMD Socket Connections
Router Patches Socket Connections Through to ITOS Systems, Process Controlled by Automated Scheduling System
THEMIS Mission Operations Peer Review Mission Operations − 23UCB, November 4, 2003
Pass Scheduling
Advanced Pass Scheduling Functions− SatTrack Generates View and Link Access Periods for All Satellite / Ground
Station Combinations− Population of Scheduling Database with View and Link Access Periods− Scheduling Engine Calculates Support Priorities by Maximizing a Figure of Merit− Interfaces to Remote Scheduling Offices Allow for Automated Schedule
Exchange− Submission of Proposed Straw Man Schedule− Reception of Confirmed Pass Supports− Iterative Procedure to Satisfy As Many Constraints As Possible− Freeze Committed Passes− Extraction of Confirmed Multi-mission Schedule from Database− Generation and Distribution of Schedule Files (SMEX Schedule, SGS Timeline
File)− Real-time Scheduling of Passes via SGS Client Connections
THEMIS Mission Operations Peer Review Mission Operations − 24UCB, November 4, 2003
SatTrack Scheduling Engine
SatTrack Scheduling Engine Calculates Support Priorities− Conflict Resolution Will Be Based on Calculated Priorities− Operators Have Override Privileges for Emergencies
Calculated Priorities Based on Various Constraints− Geometric View and Dynamic Link Access Periods− Interference Avoidance When Using Multiple Ground Stations Simultaneously− Probe Status (Memory Fill, Anomalous Conditions, Emergencies)− Time Since Last Contact for Each Spacecraft or Probe− Minimum Number of Contacts Per Day and Per Orbit− Maximum Time Between Contacts for Each Spacecraft or Probe− Maximum Transmit Time Per Pass, Per Day and Per Orbit− Data Replay Requests− Assignment of Fixed Priorities in Special Cases− Ground Station Availability (Other Spacecraft Supports, Downtime, Staffing)
THEMIS Mission Operations Peer Review Mission Operations − 25UCB, November 4, 2003
Pass Scheduling System
Multi-mission Pass Scheduling System
THEMIS Mission Operations Peer Review Mission Operations − 26UCB, November 4, 2003
Remote Probe Status Monitoring
SatTrack Interface to ITOS Data Point Server (DPS)− SatTrack DPS Client Program Connects to SatTrack Gateway Server− One Instance of DPS Client Can Handle Multiple Probes Simultaneously− Receives Pass Schedule Information in Real-time− Connects/Disconnects to/from ITOS Supporting a Pass for a Given Probe− Connects/Disconnects Can Be Interleaved for Multiple ITOS Systems− Polls Values for List of Mnemonics and Saves Values in Local Database− Periodically Updates Probe Specific Web Pages− Generates Constellation Overview Page with Hyperlinks to Pages for
Individual Probes− Probe Status (Overall Green/Yellow/Red Condition, Battery Charge, SSR Fill,
Tank Pressure, Various Temperatures, Attitude, Spin Rate, Instrument Status)− Last and Next Contact (Via Facility X, Schedule Obtained from SGS)
− Performs Yellow and Red Limit Checking with FOT Notification
THEMIS Mission Operations Peer Review Mission Operations − 27UCB, November 4, 2003
Probe Clock Adjustment
Proposed Probe Clock Adjustment− ITOS Compares Frame Transmit and Receive Times and Adjusts Clock Delta in
Real-time During Pass Supports: ΔT = Tframe received − Tframe transmitted − Trange delay
− ATS Loads Include Commands to Periodically Adjust Clock Drift in Small Steps− Requires Time Stamping of Telemetry Transfer Frames on Probes and by All
Ground Stations (Ideally with Accuracy of 1 ms)− Requires Range Information from SatTrack Gateway Server for Specified Time
(e.g. Frame Receive Time at Ground Station) When Requested by ITOS− Requires Certain Flight Software Features
− Capability to Set Coarse UTC Offset to Mission Elapsed Time− Capability to Set Fine UTC Offset (Small Delta to Coarse Offset)− Capability to Add Small Delta Offsets from ATS Load to Eliminate Clock Drift
− Scheme with Both Ground Controlled and ATS Controlled Options Allows for Maintaining Probe Clocks Well Within Required Absolute Accuracy of ± 500 ms
THEMIS Mission Operations Peer Review Mission Operations − 28UCB, November 4, 2003
Ground Controlled Clock Adjustment
THEMIS Mission Operations Peer Review Mission Operations − 29UCB, November 4, 2003
Attitude Determination
Real-time, Ground-based and On-orbit Attitude Determination− Slew Monitoring During Maneuvers for Fault Protection− Data Provided by Sun Sensor and Inertial Reference Units− Sensor Data Processed in Real-time− Cross-calibration of Sun Sensor with FGM Near Perigee
Post-pass, Ground-based Attitude Determination− Required for Science Data Analysis− Data Provided by Sun Sensor and FGM− Determine Attitude Accurately for Selected Orbit Arcs and/or Back Orbits− Attitude Solution Obtained with MSASS
THEMIS Mission Operations Peer Review Mission Operations − 30UCB, November 4, 2003
Attitude Determination
Pre-flight Testing and Validation− Representative Command Profile Required to Perform End-to-end Tests for All
Operational Scenarios for Each Probe− Post-test Analysis of VirtualSat Archive Files and Captured Telemetry Used to
Validate ACS Flight Software for Thruster Control, On-orbit Attitude Determination and Fault Protection
− Captured Telemetry from VirtualSat Used to Validate Ground-based Attitude Determination Software
On-orbit Calibration− Test Fire All Thrusters and Assess Attitude and Spin Rate Changes− Align Magnetometer to Probe Spin Axis With 0.5 deg Accuracy− Average IRU Measurements to Determine Bias− Perform Trending Analysis to Determine Precession Versus Time
THEMIS Mission Operations Peer Review Mission Operations − 31UCB, November 4, 2003
Orbit Determination
Orbit Determination Based on Two-way Doppler Tracking− Ground Stations Provide Tracking Data in Universal Tracking Data Format
(UTDF)− One Station Sufficient to Provide Required Accuracy
(10 km at Perigee, 100 km at Apogee)− Data from Multiple Stations Yield Better Solution− UTDF Files Processed with GTDS to Obtain New Orbit Solutions− New State Vectors Used in Turn to Generate Updated Planning Products
Digital Range Measurement System− Technology Demonstration During Second Year− Measures Round-trip Delay of Digital Data Stream− SatTrack/ODT Performs DRMS Based Orbit Determination Functions
THEMIS Mission Operations Peer Review Mission Operations − 32UCB, November 4, 2003
DRMS Design
THEMIS Mission Operations Peer Review Mission Operations − 33UCB, November 4, 2003
DRMS Implementation
DRMS Hardware Implementation− Use Dual PTP NTs for Simultaneous Probe Commanding and DRMS Operations− Uplink Uses Two Subcarriers at 16 kHz and 128 kHz− Downlink Uses Two Subcarriers at 1024 and 128 kHz− Pseudo-random Sequence of 216-1 Bits Transmitted at Rate of 32 kbps− Unique Range Determination to 300,000 km or 47 RE
DRMS Software Development− Simultaneously Read Outgoing and Incoming Data Streams− Perform Automated Shifting of Delay to Find Maximum Correlation− Restrict Delay Search Once Delay Found with High Confidence
Required BGS System Upgrades for DRMS− DRMS Hardware (Linux Computer) for Signal Analysis− Upgrade of Existing Backup PTP (Subcarrier Demodulator and Bit Synchronizer)− Additional Matrix Switch for Baseband Signal Routing− DRMS Software for Determination of Range Delay
THEMIS Mission Operations Peer Review Mission Operations − 34UCB, November 4, 2003
BGS Requirements
RF CompatibilityClose S-Band Forward and Return Link with Any Probe at Any Range, Using Appropriate Data Rates
Circular Polarization (RHCP or LHCP)Figure of Merit (G/T) > 24.0 dB/K at 5 º ElevationTransmit Power 200 W (EIRP > 66 dBW)
Two-way Doppler TrackingDigital Range Measurement System as Technology Demonstration
Data CompatibilityViterbi Plus Reed-Solomon Decoding and Error CorrectionCCSDS Transfer Frame ProcessingTelemetry Data Routing by Virtual Channel IDsCommand ForwardingBGS 11-m Antenna
THEMIS Mission Operations Peer Review Mission Operations − 35UCB, November 4, 2003
Apogee Labs Doppler Tracking System− Carrier Doppler Measurement System (CDMS) and Track Data Formatter (TDF)− Time Code Generator Needs 10 pps Output
ACU-21C Hardware and Software Upgrades− Parallel Interface for Fast Angle Readout
Transmit Chain Upgrade− SSPA Upgrade to 250 W− Low-loss Transmit Coax Cable− Additional Fiber-optic Cables
Optional Receive Chain Upgrade− Replace LNAs to Improve G/T
Pedestal Environment Monitor Backup Power Via Existing Generator and UPS
BGS Upgrades
THEMIS Mission Operations Peer Review Mission Operations − 36UCB, November 4, 2003
BGS Control Software Upgrades
SatTrack/MCS Software Upgrades− Control Apogee Labs Model 7701 CDMS− Control Apogee Labs Model 2208 TDF− Control DRMS System Via Network Sockets− Control Dual SSPAs via RS-232 Interfaces− Read-out Second Environment Monitor in Pedestal− Read-out Status from Multiple UPS
THEMIS Mission Operations Peer Review Mission Operations − 37UCB, November 4, 2003
Doppler Tracking Tests
Rationale for Doppler Accuracy Tests− THEMIS Orbit Determination Based on Two-way Doppler Tracking− Doppler Accuracy Difficult to Predict for THEMIS Ground System Configuration− Doppler Signal Extracted from 2nd Local Oscillator in Telemetry Receivers− Perform Tests to Establish Baseline to Predict Accuracy of Range Rate
Measurements as Function of CNR for BPSK and PSK/PCM/PM Modulation− Predicted Accuracy Will Tell How Many Tracking Arcs Are Needed to Perform
Orbit Determination for the THEMIS Mission− Required Accuracy 10 km at Perigee and 100 km at Apogee
Test Sequence− Functional Checkout of Equipment− Long Loop RF Tests with Unmodulated Carrier and Telemetry Playback− On-orbit Tests with FAST Spacecraft
THEMIS Mission Operations Peer Review Mission Operations − 38UCB, November 4, 2003
Test Schematic
Schematic Diagram for Doppler Accuracy Tests
THEMIS Mission Operations Peer Review Mission Operations − 39UCB, November 4, 2003
Sources for Doppler Errors
Potential Sources for Doppler Errors− Synchronization of Timing Signals Is Very Critical− All Reference Signals Need to Be Generated By the Same Source
− 5 MHz RF Reference for Phase-lock Loops− 10 pps Clock for Triggering Measurements− IRIG-B Time Code for Time Tagging Measurements
− Lack of Synchronization Causes Errors− Lack of Synchronization Between 5 MHz Reference and 10 pps Clock Causes
Doppler Bias and Large Fluctuations in Doppler Signal− Lack of Accuracy in IRIG-B Time Code Causes Doppler Bias
− Receivers Need to Lock Cleanly− Receiver Firmware Can Cause False or Imperfect Lock Under Certain Conditions
Related to Remote Control Functions− False Lock Causes Large Doppler Bias
THEMIS Mission Operations Peer Review Mission Operations − 40UCB, November 4, 2003
Loop-back Doppler Tests
Initial Loop-back Tests Performed− Unmodulated Carrier Signal− Transmitted at Low Power from Test Dipole at Apex of 11-m Reflector− RHCP Receiver in BPSK Mode, 3 kHz Loop Bandwidth− AGC Level in Receiver 20 dB− Recorded Tracking Data for 6 min− Measured Average Range Rate: −0.00000470 km/s− Measured Range Rate Error (1-σ): 0.00012869 km/s
THEMIS Mission Operations Peer Review Mission Operations − 41UCB, November 4, 2003
Loop-back Doppler Tests
THEMIS Mission Operations Peer Review Mission Operations − 42UCB, November 4, 2003
On-Orbit Doppler Tests
Initial On-Orbit Test Performed With HESSI Spacecraft− HESSI Has a Transceiver – Two-way Doppler Tracking Not Possible− TDF Was Configured for Two-way Mode in Preparation of Tests with FAST− Graphs on Following Slides Are Therefore Not Scaled Properly− Test However Demonstrates Functionality of System− Brief Data Drop-out Occurred When Spacecraft Switched Antennas (2nd Graph)
THEMIS Mission Operations Peer Review Mission Operations − 43UCB, November 4, 2003
On-Orbit Doppler Tests
THEMIS Mission Operations Peer Review Mission Operations − 44UCB, November 4, 2003
On-Orbit Doppler Tests
THEMIS Mission Operations Peer Review Mission Operations − 45UCB, November 4, 2003
Mission Operations Phases
Launch & Early Orbit Operations− Probe and Instrument Checkout− Maneuver Operations for Initial Orbit Placement− Contingency Operations
Normal Operations− Science Data Acquisition− Maneuver Operations for Orbit Optimization− Contingency Operations
Mission Termination Operations− Maneuver Operations to Initiate Re-entry− Instrument Shutdown
THEMIS Mission Operations Peer Review Mission Operations − 46UCB, November 4, 2003
L&EO Operations
Launch & Early Orbit Operations− Delta II Launch Sequence with Release of Probes− Round Robin State-of-Health Monitoring− Initial Attitude and Orbit Determination− Uplink of First Set of Command Loads to Each Probe− IDPU and FGM Power-up With Pre-deployment Calibration− Deployment of Magnetometer Booms− Cross-calibration of Magnetometers While Probe Separations Are Still Small − Systematic Instrument Power-up and Check-out− Test Fire and Calibrate Each Thruster on Each Probe− Spin Up to 30 r.p.m. with Calibration of Tangential Thrusters as Byproduct− Decision of Probe Placement− Discrete Pairs of Apogee and Perigee Maneuvers for Placement into Final
Mission Orbits (Reorientation – Continuous Burn – Reorientation Sequence)− Maneuvers Performed While in Contact with Ground Stations and/or TDRSS
THEMIS Mission Operations Peer Review Mission Operations − 47UCB, November 4, 2003
Launch & Early Orbit Profile
13-Oct-2006
23-Dec-2006
THEMIS Mission Operations Peer Review Mission Operations − 48UCB, November 4, 2003
Maneuver Planning and Execution
Maneuver Planning and Execution− Determine Pre-maneuver State Vector and Probe Attitude− Perform Maneuver Analysis with Current and Target State Vectors− Verify Delta V Budget− Develop Detailed Thruster Firing Sequence− Perform Contact Schedule and Shadow Analysis− Validate Probe Configuration and Maneuver Sequence on Probe Simulator− Establish Two-way Communications with Probe− Turn off ESA and SST High-voltage Supplies, Place SST into Attenuated Mode− Uplink Command Sequence to Perform Reorientation and Orbit Maneuvers− Download and Verify Command Buffer− Verify Firing Attitude− Monitor Maneuver Execution in Real-time (Tank Pressure, Attitude, Temps.)− De-configure Probe Systems and Monitor Health and Safety− Determine New Orbit and Attitude
THEMIS Mission Operations Peer Review Mission Operations − 49UCB, November 4, 2003
Flight Operations Functions
Ground Operations Functions
“Look Ahead” Orbit Propagation Indicates
Upcoming Maintenance Maneuver is Desired
Current/Desired Orbit/Attitude
used in GMAN
Specific Maneuver
Events, Attitudes, and Durations
Formulated
Discrete Thruster Profile and Pulse Sequence Formed
Discrete Stored Command Sequence Generated via MPS
Upload TLM Table, Firing Sequence, &
Downlink Rate Selection
Offline Validation of Entire Stored Command
Sequence Performed on Probe Hi-Fidelity Test-bed
Power-up Gyro’s,
Catalyst Bed Heaters (Pre-
Heat)
Downlink On-Board CMD
Buffer
Compare Flight to Ground Reference
Image to Verify Proper
Sequence Load
Verify CMD & TLM link via GN, TDRSS, USN, or DSN
Verify Current Attitude via Sun Sensor
Data
Verify Gyro Performance, Catalyst
Bed Heater Functionality,
Propellant Tank Pressure, Valve/Fuel Line Temperatures &
States, and Pre-Maneuver Attitude
Power-off Catalyst Bed
Heaters
Execute Burn Sequence
Periodic Long-Term Calibration of Pulse Timing and
Thruster Performance
Monitor Key Temperatures,
Attitude, and State Vector
On-Board Failure Detection/Correction
(FDC) Logic (gyro rates, sun-sensor attitude limits, etc) Aborts Sequence if
Anomaly is Detected
Power Down Gyros
Verify Tank Pressure, General
Probe Health & Safety, 2-
Way Ranging
Turn Off Transmitter
Determine New Orbit and New Attitude
Typical Maneuver Sequence
THEMIS Mission Operations Peer Review Mission Operations − 50UCB, November 4, 2003
Instrument Commissioning
Instrument Commissioning1. IDPU Turn-on As Soon As Probe Power System Is Stable and Temperature Below
Maximum Operating Limit, Verification of Nominal Voltages and Currents, Command Communications and DCB Functionality
2. FGM Turn-on, Power Verification and Uplink of Parameter Load for 32 Hz Bx, By and Bz, Verification of Sensitivity Control on Each Axis, Select Sensitivity
3. EFI Turn-on, Power Verification and Configuration for 32 Hz E & B Sample Rates4. SCM Turn-on, Power Verification and Activation of Calibration Sequence5. Magnetometer Boom Deployment With FGM at 32 Hz Real-time Science TLM6. SST Turn-on After Initial Outgasing Phase, Power Verification, High-voltage Ramp-
up and Attenuator Functional Test7. ESA Turn-on After Initial Outgasing Phase, Power Verification, Cover Release and
High-voltage Ramp-up8. EFI Spin Plane Boom Deployment − Procedure Controlled by IDPU9. EFI Axial Boom Deployment − Procedure Controlled by IDPU
THEMIS Mission Operations Peer Review Mission Operations − 51UCB, November 4, 2003
Normal Operations
Mission Planning During Normal Operations− Preparation of the Conjunction Season− Ground Station Contact Schedules
Probe Command and Control− Probe Health and Safety Monitoring− Recovery of Science and Engineering Data− Command Load Uplink Twice Per Week− Instrument Configuration and Data Trending
Attitude & Orbit Determination− Routinely Performed Multiple Times per Week
Maneuver Planning and Execution− Orbits of Probes 1,2,5 Adjusted Few Times Per Year to Optimize Conjunctions− Orbits of Probes 1 & 2 Adjusted Annually to Counteract Lunar Perturbations
THEMIS Mission Operations Peer Review Mission Operations − 52UCB, November 4, 2003
MOC Staffing
MOC Staffing During Launch & Early Orbit Operations− UCB Flight Operations Team− 24 Hour Staffing with Prime and Secondary Shifts− Critical Commanding During Prime Shift Only− Swales and UCB Engineering Team on Console During Prime Shift− Instrument Scientists on Console During Instrument Commissioning
MOC Staffing During Normal Operations− THEMIS Follows FAST / RHESSI / CHIPS Model− Normal Operations Eventually Run with 8 x 5 Staffing− Lights-out Operations During Off-hours Successfully Demonstrated− Transition to Autonomous Operations After First Tail Season− Attitude & Orbit Maneuvers Always Treated as Special Operations
THEMIS Mission Operations Peer Review Mission Operations − 53UCB, November 4, 2003
Telemetry Requirements
Baseline Requirements for Instrument and Probe Bus Data Recovery− 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 − Resulting Science Telemetry Data Volume 480−640 Mbits / Orbit / Probe− Required Downlink Time 16−21 min Orbit / Probe at Data Rate of 512 kbps
− Each Probe Bus Accumulates Up to 87 Mbits of Engineering Data per Orbit− Apply 12% Overhead for CCSDS Formatting, 14% for RS Code Symbols− Resulting Engineering Telemetry Data Volume 111 Mbits / Orbit / Probe− Required Downlink Time 4 min / Orbit / Probe at Data Rate of 512 kbps
− BGS as Primary Ground Station with 1070 Passes / Year of 15−30 min Duration− Additional Secondary Network Stations Support 300 Passes / Year− Other BGS Tracking Passes Scheduled for Orbit Determination and Probe Monitoring− Contingency Passes Available (60−100 % Margin)
THEMIS Mission Operations Peer Review Mission Operations − 54UCB, November 4, 2003
Science Modes & Data Compression
Science Modes− Slow Survey (SS)− Fast Survey (FS)− Particle Burst (PB)− Wave Burst (WB)− Mode Control Via ATS and/or On-board Triggers
Data Compression− Selectively Enabled / Disabled− Applied Prior to Downlink− Segmentation into 64 Byte Input Blocks− Output Blocks Are Variable in Length− Relatively Short Block Size Minimizes Impact from Bit Errors− Compression Factor of 1.5-2.0 Achievable− Depends on Instrument Data Type
THEMIS Mission Operations Peer Review Mission Operations − 55UCB, November 4, 2003
Link Analysis
Telemetry Link
Frequency 2234.0 MHz
Modulation BPSK
Probe Antenna Gain -3.0 dBic
Probe EIRP 2.5 dBW
Range 20,000 km
Path Loss 185.5 dB
Polarization and Pointing Losses 1.0 dB
Ground Station G/T (11-m Antenna) 24.0 dB/K
Data Rate 1024.0 kbps
Bandwidth 2048.0 kHz
Coding Gain RS + Rate-1/2 Convolutional 8.0 dB
BER 10-6
Required Eb/No 2.5 dB
Predicted Eb/No 9.5 dB
Implementation Loss 2.5 dB
Link Margin 4.5 dB
Command Link
Frequency 2057.141667 MHz
Modulation PCM/PSK/PM
Ground Station Antenna Gain 45.5 dB
Ground Station EIRP (11-m Antenna) 66.5 dBW
Range 197,000 km
Path Loss 204.6 dB
Polarization and Pointing Losses 1.0 dB
Probe G/T -38.6 dB/K
Data Rate 1.0 kbps
Bandwidth 1.0 kHz
Coding Gain 0.0 dB
BER 10-6
Required Eb/No 10.5 dB
Predicted Eb/No 19.2 dB
Implementation Loss 2.5 dB
Link Margin 6.2 dB
THEMIS Mission Operations Peer Review Mission Operations − 56UCB, November 4, 2003
Telemetry Rates
Downlink Mode Schedule Duration Range Modulation Data Rate
Stored Science and Engineering Downlink 1 x / Orbit / Probe 30 min 750 – 15,000 km BPSK 1,024 kbps
Stored Science and Engineering Downlink 1 x / Orbit / Probe 30 min 2,500 – 20,000 km BPSK 512 kbps
Stored Science and Engineering Downlink 1 x / Orbit / Probe 30 min 10,000 – 30,000 km BPSK 256 kbps
Stored Science and Engineering Downlink 1 x / Orbit / Probe 30 min 20,000 – 40,000 km BPSK 128 kbps
Real-time Engineering Downlink with Ranging 1 x / Day / Probe 30 min 30,000 – 60,000 km PCM/PSK/PM
1.024 MHz S/C 64 kbps
Real-time Engineering Downlink with Ranging 1 x / Day / Probe 30 min 50,000 – 75,000 km PCM/PSK/PM
1.024 MHz S/C 32 kbps
Real-time Engineering Downlink with Ranging 1 x / Day / Probe 30 min 65,000 – 100,000 km PCM/PSK/PM
1.024 MHz S/C 16 kbps
Real-time Engineering Downlink with Ranging 1 x / Day / Probe 30 min 80,000 – 150,000 km PCM/PSK/PM
1.024 MHz S/C 8 kbps
Real-time Engineering Downlink with Ranging 1 x / Day / Probe 30 min 120,000 – 200,000 km PCM/PSK/PM
1.024 MHz S/C 4 kbps
Real-time Engineering Downlink via TDRSS
Contingency & Real-time Maneuver Support 30 min 5,000 – 42,500 km PCM/PSK/PM
1.024 MHz S/C 1 kbps
THEMIS Mission Operations Peer Review Mission Operations − 57UCB, November 4, 2003
Pass Support Plan
Baseline Probe Contact ScheduleDay Number
Modulo 4Probe 1 Probe 2 Probe 3 Probe 4 Probe 5
1 Data Recovery30 min
Data Recovery30 min
Data Recovery 30 min
Data Recovery 30 min
Data Recovery 30 min
2Tracking & Monitoring
30 min
Tracking & Monitoring
30 min
Data Recovery 30 min
Data Recovery 30 min
Data Recovery 30 min
3Tracking & Monitoring
30 min
Data Recovery 30 min
Data Recovery 30 min
Data Recovery 30 min
Data Recovery 30 min
4Tracking & Monitoring
30 min
Tracking & Monitoring
30 min
Data Recovery 30 min
Data Recovery 30 min
Data Recovery 30 min
Blue: Required Passes for Recovery of All Telemetry Data at a Rate of 512 kbpsRed: Additional Passes Available for Tracking and Probe Monitoring at Lower Data Rates
THEMIS Mission Operations Peer Review Mission Operations − 58UCB, November 4, 2003
Ground Station Support
Ground Station Support Options− Option 1:
− Berkeley, CA, 11-m (Primary)− Wallops Island, VA, 11-m (Secondary TLM/CMD))− Poker Flat, Alaska, 11-m (Possible Back-up TLM/CMD)− Santiago, Chile, 9-m (Secondary TLM Only)− Hartebeesthoek, South Africa, 10-m (Secondary TLM Only)
− Option 2:− Berkeley, CA, 11-m (Primary)− Dongara, Australia, 13-m (Secondary TLM/CMD)− South Point, Hawaii, 13-m (Secondary TLM/CMD)− North Pole, Alaska, 13-m (Back-up TLM/CMD)
THEMIS Mission Operations Peer Review Mission Operations − 59UCB, November 4, 2003
Pass Requirements
Pass Requirements Per Mission Phase− L&EO 4 Months− First Year Science− Second Year Science
THEMIS Probe L&EO Passes First Year Passes Second Year Passes
1 120 92 922 120 183 1833 120 365 3654 120 365 3655 120 365 365
Total 600 1370 1370
THEMIS Mission Operations Peer Review Mission Operations − 60UCB, November 4, 2003
Pass Schedule BGS & NASA/GN
THEMIS Mission Operations Peer Review Mission Operations − 61UCB, November 4, 2003
Pass Schedule BGS & NASA/GN
THEMIS Mission Operations Peer Review Mission Operations − 62UCB, November 4, 2003
Pass Schedule BGS & NASA/GN
THEMIS Mission Operations Peer Review Mission Operations − 63UCB, November 4, 2003
Pass Schedule BGS & NASA/GN
THEMIS Mission Operations Peer Review Mission Operations − 64UCB, November 4, 2003
Pass Schedule BGS & USN
THEMIS Mission Operations Peer Review Mission Operations − 65UCB, November 4, 2003
Pass Schedule BGS & USN
THEMIS Mission Operations Peer Review Mission Operations − 66UCB, November 4, 2003
NASA GN and SN Resource Requirements in PSLA− THEMIS PSLA Reviewed by GSFC/Code 450− PSLA Under Code 450 Configuration Control− Compatibility Test Van for GN/SN End-to-end Testing
Additional Documentation Requirements− Detailed Mission Requirements – Draft at CDR− RF ICD (Ground to TDRSS) – Draft at CDR
Data Flows and Scheduling for Ground Testing & Mission Operations− Supported and Coordinated by GSFC/Code 450
Ground System Development− Support of Experiments with Berkeley Ground Station to Determine Accuracy of
Two-way Doppler Tracking
GSFC/Code 450 Support
THEMIS Mission Operations Peer Review Mission Operations − 67UCB, November 4, 2003
NTIA License
NTIA License Status− Frequencies Tentatively Assigned by GSFC Spectrum Management Office− Identical Frequencies for All Probes
− Telemetry: 2234.0 MHz− Command: 221 / 240 ∙ 2234.0 = 2057.141667 MHz
− DoD Currently Reviews Frequency Assignment− BGS Interference Survey Has Been Performed – No Offending RF Sources− NTIA Forms Have Been Provided by All Ground Stations− Formal NTIA Stage 2 License Application Under Development− Application Will Be Submitted in Mid November 2003− Stage 2 Approval With Confirmed Frequencies Expected by August 2004− Transponders Are Long-lead Items and Need to Be Procured Sooner− Risk Is Tentatively Assigned Frequencies May Be Denied by Non-U.S. Members
THEMIS Mission Operations Peer Review Mission Operations − 68UCB, November 4, 2003
Network Plan & IT Security
NASA Network Security Requirements Driven by NPG 2810.1, Security of Information Technology
− GSFC IT Security Outlined in Document 290-004, IONet Access Protection Policy and Requirements
− Establishes IT Network Systems Security Measures and Controls for Access to Critical NASA Resources
Documentation Requirements− Information Technology Security Plan, Risk Analysis and Contingency Plan
Closed IONet Security Compliance− Dedicated, Isolated Network and Workstations for TDRSS Access− Configuration Control by System Administrator− Network Certification and Scanning− Personnel Screening
THEMIS Mission Operations Peer Review Mission Operations − 69UCB, November 4, 2003
Acronyms
ATS Absolute Time SequenceBEARS Berkeley Emergency & Anomaly Response SystemBFDS Berkeley Flight Dynamics SystemCDMS Carrier Doppler Measurement SystemCOSPAR Committee for Space ResearchDRMS Digital Range Measurement SystemFGM Fluxgate MagnetometerGMAN General Maneuver ProgramGMSEC Goddard Mission Services Evolution CenterGTDS Goddard Trajectory Determination SystemIRU Inertial Reference UnitMSASS Multi-mission Spin Axis Stabilized SpacecraftRTS Relative Time SequenceSSPA Solid State Power AmplifierTAPS Trending and Plotting SystemTDF Track Data FormatterUTDF Universal Tracking Data FormatWDC-A-R&S World Data Center A for Rockets & SatellitesWWAS World Warning Agency for Satellites