Mission Operations Requirements Data Capture and Mission Operations Requirements Manfred Bester THEMIS Mission Operations Manager

Data Capture & Mission Operations Overview Operations Concept Data Capture and Delivery Requirements Ground Station Requirements Mission Operations Center Requirements Mission Operations Requirements

Operations Concept Summary Space Segment 5 Spinning Probes in High Earth Orbits Simultaneous Release from LV Initial Orbits Close to Final Mission Orbits of Probes 3, 4 and 5 Probes 1 and 2 Move to Their Final 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 Universal Space Network as Secondary TDRSS (SSA) and Wallops GN for Ascent, Maneuver and Contingency Support Operations Centers Mission and Science Operations Centers Co-located at U.C. Berkeley

Orbit Geometry Prior to First Year Tail Season Mission Orbits PCA 1.100 x 12.103 Re at 9.0° 5 Re / div Probe Orbital Period Orbit Geometry Prior to First Year Tail Season 1 4 d 1.500 x 31.645 Re at 7.0° 2 2 d 1.168 x 19.770 Re at 7.0° 3 1 d 1.118 x 12.127 Re at 9.0° 4 5 4 / 5 d 1.350 x 10.044 Re at 4.5°

Ground System Overview

Data Recovery 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 2 Prior to Transmission to the Ground Apply 12% Overhead for CCSDS Formatting, 14% for RS Code Symbols Resulting Science Telemetry Data Volume 480 Mbits / Orbit / Probe Required Downlink Time 16 min Orbit / Probe at Data Rate of 512 kbps Each Probe Bus Accumulates Up to 87 Mbits of Engineering Data per Orbit 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 1030 Passes / Year of 30 min Duration USN−AU (Universal Space Network, Perth) as Secondary with 340 Passes / Year Additional BGS Tracking Passes Scheduled for Orbit Determination Contingency Passes Available (60 − 100 % Margin at Each BGS and USN−AU)

Ground Station Compatibility GS.STN-1. The THEMIS ground stations shall be RF and data compatible with the space segment on both the telemetry and the command link. Rationale: Ensures telemetry can be recovered and probes can be commanded. GS.STN-2. The THEMIS ground stations shall perform Viterbi decoding and Reed-Solomon error correction on the telemetry stream. Rationale: With the appropriate link margin, error detection and correction will ensure a telemetry bit error rate of 10-6. GS.STN-3: The THEMIS ground stations shall be able to close the telemetry link at various data rates commensurate with probe range with a link margin of at least 3 dB. Rationale: Maximize probe bus and instrument data recovery as function of probe range out to 31.6 Re. Allow for telemetry reception at low data rate to support maneuvers and contingency operations.

Telemetry Data Rates Stored Science and Engineering Downlink Downlink Mode Schedule Duration Range Modulation Data Rate Stored Science and Engineering Downlink 1 x / Orbit / Probe 30 min 700 – 14,000 km BPSK 1,024 kbps 700 – 20,000 km 512 kbps 14,000 – 30,000 km 256 kbps 20,000 – 40,000 km 128 kbps Real-time Engineering Downlink with Ranging 1 x / Day / Probe 40,000 – 50,000 km PCM/PSK/PM 1.024 MHz S/C 64 kbps 50,000 – 75,000 km 32 kbps 75,000 – 200,000 km 4 kbps Real-time Engineering Downlink via TDRSS 30x During Entire Mission for All Probes Combined 5,000 – 42,500 km 1 kbps

Probe Telemetry GS.STN-4. The THEMIS ground stations shall recover a telemetry data volume of 591 Mbits / orbit / probe. Rationale: Ensures that sufficient telemetry bandwidth is available to recover both science and engineering data. GS.STN-5. The THEMIS ground stations shall split received telemetry data by Virtual Channel ID, record all data locally and route real-time data to command and control workstations via network connections. Rationale: Data stream is split for probe bus and science data processing as well as real-time command and control. GS.STN-6. The THEMIS ground stations shall buffer recovered telemetry data for at least 10 days. Rationale: Temporary backup storage in case network links are down.

Probe Commanding GS.STN-7. The THEMIS ground stations shall provide command capabilities to allow closure of the command link out to 31.6 Re with a link margin of at least 3 dB. Rationale: Ensures that sufficient effective radiated power is available to close the command link at a data rate of 1 kbps with a bit error rate of 10-7. GS.STN-8. The THEMIS ground stations shall acquire the command link using a STDN compatible acquisition sweep procedure. Rationale: Driven by probe transponder and common ground station characteristics. GS.STN-9. The THEMIS ground stations shall support the COP-1 protocol for command verification. Rationale: Ground stations receive telecommands from ITOS in form of CLTUs and forward these to the probes. Likewise, real-time telemetry transfer frames are forwarded from the probes to ITOS to close the command verification loop.

Tracking Data GS.STN-10. All THEMIS ground stations shall provide two-way Doppler tracking data in Universal Tracking Data Format (UTDF). Rationale: Two-way Doppler tracking data are required for orbit determination. GS.STN-11. The THEMIS ground stations shall transfer all tracking data to the THEMIS Mission Operations Center post-pass for orbit determination. Rationale: Primary orbit determination will be performed at the MOC using GTDS. GS.STN-12. The Berkeley Ground Station shall be the primary ground station for THEMIS and shall be equipped with additional hardware and software systems to provide two-way digital range tracking data. Rationale: Technology demonstration of enhanced orbit determination capabilities for future constellation missions. SatTrack Orbit Determination Tool will be used to process two-way Doppler and two-way ranging data simultaneously.

Pass Support Requirements Baseline Pass Support Requirements Day Number Modulo 4 Probe 1 Probe 2 Probe 3 Probe 4 Probe 5 1 Data Recovery 30 min Data Recovery 30 min 2 Tracking 3 4 Blue: Required Passes for Recovery of All Telemetry Data at a Rate of 512 kbps Red: Additional Passes Available for Tracking and Probe Monitoring

BGS Requirements RF Compatibility Data Compatibility Close 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 Elevation Transmit Power 200 W (EIRP > 66 dBW) Two-way Doppler Tracking Digital Range Measurement System as Technology Demonstration Data Compatibility Viterbi Plus Reed-Solomon Decoding and Error Correction CCSDS Transfer Frame Processing Telemetry Data Routing by Virtual Channel IDs Command Forwarding BGS 11-m Antenna

Mission Operations Center GS.MOC-1. All aspects of THEMIS Mission Operations shall be performed at the Mission Operations Center, located at UCB / SSL. Rationale: Integrated Mission Operations Center reduces overall ground systems complexity. GS.MOC-2. The Mission Operations Center shall provide hardware, software and IT networking systems to support all mission operations functions. Rationale: Provides infrastructure to perform all tasks required to operate the five probes and to recover all science and engineering data via primary and secondary ground stations. GS.MOC-3. The Mission Operations Center shall interface with other THEMIS ground system elements such as the ground stations, the TDRSS Ground Terminal and the Science Operations Center. Rationale: Ensures seamless data flow from the probes to all required ground system elements and vice versa, and exchange of all required data products.

Mission Operations Center GS.MOC-4. The Mission Operations Center shall provide secure data interfaces to allow for remote probe operation and end-to-end data flow testing during mission integration. Rationale: Allow for end-to-end data compatibility testing, telemetry page development, simulations and operator training. GS.MOC-5. The Mission Operations Center shall provide two SCAMA voice loops to allow for communications with other facilities supporting the mission. Rationale: Provide voice loops for end-to-end data flow test coordination, pre-launch simulations, launch and ground station support. GS.MOC-6. The Mission Operations Center shall adhere to NASA IT Network Security standards. Rationale: Ensures that space and ground systems are protected against unauthorized physical and network access (applies to THEMIS and other supported missions).

MOC Facility Requirements Expanded, Secure 900 ft² Operations Facility at SSL

Operations Environment NASA / GSFC GNCD Provides Support in Form of Consulting Software Tools: GTDS, GMAN, MSASS, SatTrack, ITOS, MPS, SERS Implement Database to Track Probe Configuration, Status & Anomalies

Mission Operations & Planning GS.OPS-1. THEMIS Mission Operations shall support all phases of the mission. Rationale: Mission operations include pre-launch, launch and early orbit, normal, contingency and end-of-life operations. GS.OPS-2. A complete set of ephemeris and mission planning products shall be generated to support all mission planning functions, ground contact scheduling and generation of command loads for all probes. Rationale: Generate all products based on latest state vector for each probe. GS.OPS-3. Mission planning functions shall ensure that all probes are configured and operated according to specifications, and yield optimum science data while preserving fuel and maintaining adequate margins and probe health. Rationale: Maintain optimum operational status of all probes and ensure that science requirements are met.

Probe Monitoring & Commanding GS.OPS-4. Probe state-of-health shall be monitored during real-time pass supports. Post-pass telemetry playback shall be used to examine back-orbit data for limit violations. Rationale: Monitor probe state-of-health throughout the entire orbit. GS.OPS-5. Mission operations shall include data trending to establish baseline parameters and to uncover any developing anomalous conditions early on. Rationale: Provide operational baseline and prevent risk to flight hardware due to out- of-limit operation. GS.OPS-6. Command loads generated on the ground shall be verified prior to upload. Rationale: Ensure correct probe operation and reduce operational risk.

Orbit Determination & Maneuvers GS.OPS-7. All critical commands, table loads and flight software patches shall be verified on the probe simulator prior to upload. Rationale: Minimize risk to flight hardware and software. GS.OPS-8. The orbit of each probe shall be determined with an accuracy of 10 km at perigee and 100 km at apogee based on two-way Doppler tracking data. Rationale: Adequate accuracy for ground antenna pointing and science requirements. GS.OPS-9. All orbit maneuvers shall be carefully planned and validated prior to execution. Rationale: Ensure that critical maneuver commands are correct and yield the desired orbit change at minimum fuel consumption.

Attitude Determination & Maneuvers GS.OPS-10. Attitude determination of all probes shall be ground based and shall be based on raw Sun sensor and FGM data. FGM data recorded near perigee shall be used to cross-calibrate the Sun sensor on each probe. Rationale: Ground based attitude determination is part of the Attitude Control System. GS.OPS-11. All attitude maneuvers shall be carefully planned and validated prior to execution. Rationale: Ensure that critical maneuver commands are correct and yield the desired attitude change at minimum fuel consumption. GS.OPS-12. Probe anomaly resolution shall be conducted in consultation with pertinent subsystem engineers, instrument scientists and project management personnel. Rationale: Recover probe bus and instruments to a safe operating state as quickly and efficiently as possible.

Launch & Early Orbit Operations L&EO Operations Launch & Early Orbit Operations Delta II Launch Sequence with Release of Probes Round Robin State-of-Health Monitoring Attitude and Orbit Determination Uplink of First Set of Command Loads to Each Probe IDPU and FGM Power-up Deployment of Magnetometer Booms Systematic Instrument Power-up and Check-out Decision of Probe Placement Spin Up to 30 r.p.m. with Calibration of Tangential Thrusters as Byproduct 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

Mission Profile 13-Oct-2006 23-Dec-2006

THEMIS Maneuver Summary Probe Maneuver ID Purpose of Maneuver Maneuvers 1 P1-1 − P1-5 P1-6 − P1-13 P1-14 Initial Mission Orbit Insertion Fine Tuning for Optimization of Conjunction Science De-orbit 8 2 P2-1 − P2-5 P2-6 − P2-13 P2-14 7 3 P3-1 − P3-3 P3-4 − P3-6 P3-7 − P3-8 4 P4-1 − P4-3 P4-4 − P4-6 P4-7 − P4-8 5 P5-1 − P5-2 P5-3 − P5-7 P5-8 Total 57

TDRSS Support Requirements TDRSS Shall Be Used to Support Launch and Maneuver Operations Command and Telemetry Data Rate Via TDRSS Shall Be 1 kbps TDRSS Support Summary PCA Probe Monitoring During Ascent Phase 6.0 h Probe 1 4 Apogee Raise Maneuvers Performed Near Perigee @ 1.25 h Each 5.0 h Probe 2 3 Apogee Raise Maneuvers Performed Near Perigee @ 1.0 h Each 3.0 h Probe 3 1 Apogee Trim Performed Near Perigee @ 1.0 h Each 1.0 h Probe 4 Probe 5 4 Period Change Maneuvers Performed Near Perigee @ 0.7 – 1.7 h Each Total Support Entire Mission 21.0 h

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

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 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

Science Operations Requirements Tim Quinn THEMIS Science Operations Manager

Science Operations Overview Data Acquisition and Processing Data Access and Analysis Data Archiving and Distribution Instrument Commanding

Data Acquisition and Processing Science Operations Data Acquisition and Processing Spacecraft Data – Spacecraft data (Virtual Channel – VC) files are delivered from the ground stations to the SOC server over the Internet and Local Area Network (LAN) via FTP Initial checks for data gaps and missing frames are performed VC files (Level 0) -> Level 1 data files Packets are stripped out of Virtual Channels and are filed by Application Identifier (APID) Level 1 data files -> Summary Plots IDL routines produce GIF and Common Data Format (CDF) files for viewing and downloading from WWW Ground Based Observatory (GBO) Data - Image data are mirrored from University of Calgary site

Data Acquisition and Processing Science Operations Data Acquisition and Processing Ground Based Observatory (GBO) Data - Magnetometer data mirrored from University of Alberta GBO data combined with spacecraft data into integrated summary plots

Data Access and Analysis Science Operations Data Access and Analysis Complete spacecraft data set is accessible from local disk array WWW access to summary data GBO data accessed from Canadian sites Imager data from University of Calgary Magnetometer data from University of Alberta Data validated on a daily basis by designated operations scientist (TOHBAN) Assures data quality Monitors housekeeping data trends Identifies and tabulates geophysical events of special interest Software tools include include Extensive library of IDL programs Science Data Tool (SDT)

Data Access and Analysis Science Operations Data Access and Analysis Software distributions will be made available to the Co-I’s Training sessions at UCB for Co-I’s and Guest Investigators

Data Archival and Distribution Science Operations Data Archival and Distribution Raw and processed data (Level 0 & 1) are archived to disk array and DVD Data volume ~100 GBytes/Year (All Spacecraft) Summary Plots (GIF plots and CDF files) Data Volume ~100 GBytes/Year GBO data sets are mirrored from University of Calgary and University of Alberta Data volume 5-10 TBytes/Mission (All sites) DVD’s are distributed to NSSDC and Co-I institutions

Instrument Commanding Science Operations Instrument Commanding Stored command loads produced using modified version of existing FAST system Loads transferred to MOC for integration into overall spacecraft load and uplink to spacecraft