Spacecraft Operations
Course
Course Content
The following subjects and topics will be addressed during the Spacecraft Operations Course
Table of Content
TABLE OF CONTENT ... 2
INTRODUCTION AND OVERVIEW... 2
BACKGROUND... 3 SPACE ENVIRONMENT... 3 SATELLITE DESIGN... 3 FLIGHT DYNAMICS ... 3 ORBIT ASPECTS... 3 MISSION ANALYSIS... 4 ATTITUDE DYNAMICS... 5
FLIGHT DYNAMICS ON-CONSOLE TRAINING... 5
MISSION PLANNING ... 5
CONCEPTS AND METHODS... 5
MISSION PLANNING ON-CONSOLE TRAINING... 5
SATELLITE OPERATIONS... 6
PROJECT MANAGEMENT... 6
MISSION OPERATIONS... 6
TELEMETRY, COMMAND, RANGING SUBSYSTEM (TCR) ONBOARD SUBSYSTEM... 7
DATA HANDLING (DH) SUBSYSTEM... 7
AOCS SUBSYSTEM OPERATIONS... 7
PROPULSION SUBSYSTEM OPERATIONS... 8
PWR SUBSYSTEM OPERATIONS... 8
THM SUBSYSTEM OPERATIONS... 9
REPEATER SUBSYSTEM OPERATIONS... 9
SCIENTIFIC INSTRUMENTS OPERATIONS... 10
ON CONSOLE TRAINING... 11
GROUND SEGMENT ... 12
GROUND STATION NETWORKS... 12
GROUND STATION DESIGN... 12
CONTROL CENTRE FUNCTIONS... 13
Introduction and Overview
• Organisation of the Course
o Welcome o Time plan o Transportation o Structure of Lectures
• Overview of DLR
o General Overview
o Site Oberpfaffenhofen/Weilheim
• GSOC Tasks
o Experience
o Ongoing and Future Missions
Background
Space Environment
• The range of environment encountered
o Pre-launch o Launch vehicle o Operational
• The effects on spacecraft design
o Vacuum o Electromagnetic Radiation o Particle radiation o Zero gravity o Atmospheric drag o Debris o Atomic oxygen o Solar wind o Radiation pressure Satellite Design
• The definition of space system engineering
• Mission Requirements
• Mission Objectives
• Specific System Design Tools
o Design Drivers o Trade-offs
• Concurrent Engineering
• Examples of satellite system design for a range of spacecraft missions
• Alternative approaches to spacecraft system design
Flight Dynamics
Orbit Aspects • Introduction
• Orbit Determination
o Concept of orbit determination o Tracking data types
Angle measurements Range measurements Doppler measurements GPS measurements o Achieved accuracy • Support of Operations
o Ground System Network Support
Scheduling support
Antenna pointing predictions
o Mission Operations Support
Event prediction, support of SOE generation Loading of on-board orbit propagator
• Manoeuvre Planning
o Orbit maintenance of a LEO
Node, eccentricity and inclination control Separation control
o Geostationary injection manoeuvres o Geostationary station keeping
Mission Analysis • Introduction • Orbital Mechanics o Orbital Elements o Co-ordinate Systems • Types of Missions
o Earth observation missions o Scientific missions
o Geostationary missions o Constellations
• Mission Analysis Examples
o Earth Observation Mission
First acquisition Ground track Repeatability Station visibility Coverage Shadows Lifetime o Geostationary Mission Scenario Transfer orbit
Ground station network First acquisition
Injection strategies Constraints
Launch window
Attitude Dynamics • Definition of attitude
• Coordinate systems
• Parametrisation
o Direction cosine matrix o Euler angles
o Quaternions
• Attitude determination
o a simple algorithm and its application
• Attitude control
o the loop and how to work with it
Flight Dynamics On-Console Training
• Launch and Early Orbit Phase of a Low Earth Orbiting satellite
o Mission preparation (Ground station scheduling with nominal injection
elements)
o Sequence of orbit determinations (over 4 orbits) o Replanning of ground station schedule
o Display of CHAMP orbit with the LEO software
• Station Acquisition of a geostationary satellite:
o Planning of station acquisition maneuvers
A demonstration with examples and a training how to use flight dynamic tools will be included in this session.
Mission Planning
Concepts and Methods • Overview
• Fundamentals
• Meta Language & Problem Modelling
• Increment planning o long-term o short-term o re-planning • Envelope Method • Optimisation Methods
Mission Planning On-Console Training
GSOC's generic Mission Planning System:
• ATLAS
• PLATO
• TIMON
A demonstration with examples and a training how to use the mission planning tools will be included in this session.
Satellite Operations
Project Management
• Tasks and Tools from Project Preparation through Execution
o tasks of the Project Management necessary for acquisition, preparation and
execution of a commercial project (reference project: EUTELSAT W Series)
o tools and facilities necessary for successful completion of this type of mission
• Management Tasks and Tools during:
o Acquisition Phase
Marketing and Creation of the Proposal Contract Negotiations and Signature
o Preparation Phase
From Kick-Off to Operational Readiness Review (ORR) In-house activities and management of the project
Management of subcontracts and execution of options; conflict management
Customer Interface Management (formal reviews) From ORR to Lift-Off
Administrative activities required for LEOP preparation and execution
Technical management to secure the Launch Readiness and LEOP performance
o Mission Execution Phase
the Project Manager will act as the Mission Operations Director Management of the LEOP (on console position)
Management of the Stand By Phase
Mission Operations
• Mission Preparation Phase
o Definition, generation and implementation of operational tools
Operational documentation (Hard- and Software)
o Test and training
Test and validation of all tools End-to-end tests
Cross-training Simulations Rehearsals
• Mission Execution Phase
o General tasks, Staffing Profile o LEOP operations
o IOT Operations
o Routine Operations (different orbits - different mission scenarios)
LEO (e.g. CHAMP)
High eccentric (e.g. EQUATOR-S) Geostationary
Deep Space
• Post Mission Phase
o Data Archiving and Analysis o Mission Reports
o Lessons Learned o Stand-By
Telemetry, Command, Ranging Subsystem (TCR) Onboard Subsystem • Subsystem overview
o Specific Functions (geostationary and scientific Satellites) o Automated operations functions (U/L, D/L)
o Operation performed via ground control o Modifications (coding, coherent, ranging etc.)
• Initial Acquisition and Commissioning Phases
o Problem conditions and actions required
o Differences between geostationary and scientific missions
• Routine Phases
o On board operations planning
o Monitoring (ground station parameters, Beacon, derived parameters) o Deviation from normal operations and impact
o Trouble shooting
Data Handling (DH) Subsystem • Subsystem overview
o Specific Functions (Geostationary and Scientific Satellites) o Automated operations
o Operation performed via ground control o CCSDS (influence on operations) o Software uploads
o Deviation from normal operations and impact
• Time tagged commands
o Sequence management
• Onboard data management
o Payload data distribution o Storage
o Memory dump
AOCS Subsystem Operations • Introduction to AOC subsystem
o Components o Functions
o Structure
• Description of sensors (optical, inertial, etc.)
• Description of actuators (thrusters, wheels, magnetic torquer)
• Discussion of onboard control algorithm and complexity of the control unit w.r.t.:
o the mission profile (commercial broadcasting, scientific, deep space, etc.) o levels of on-board autonomy
o and required ground support
• Description of operational modes with reference to the current mission phase
• Discussion of failure detection and solution (on-board, on-ground)
• Examples of routine and contingency subsystem operations
o Launch and Early Orbit Phase o Commissioning Phase
o Routine Phase
• Tendencies of future AOC subsystem development
Propulsion Subsystem Operations
• Typical Layout of a bipropellant propulsion system
o Pressurisation System o Propellant System o Thruster Configuration
o Pressure and temperature sensors
• Rules and Guidelines for subsystem operations
o Operational Modes
Autonomous operation Deterministic activities
o FDIR
Pressurisation system leaks Thruster failure Sensor failure o Real-time monitoring Outside activities During activities o Offline analysis Propellant budget Thruster performance Helium budget
Hardware characterisation, e.g. pressure regulator, check valves
o Performance prediction PWR Subsystem Operations • Introduction • Typical Layout o Power Generation o Power Storage
o Power Control and Distribution o Redundancy
o Operational Modes and Associated Procedures o Ground Support Software
Derived / Calculated Parameters Configuration and Range Checks Pre-Pass, R/T and Post-Pass Operations
o Comparison of Different Missions
GEO Missions vs. LEO Missions Scientific vs. Commercial Missions
Past vs. Present Missions, and Future Trends
THM Subsystem Operations • Typical Layout
o Passive Control Methods o Active Control Methods o Temperature Sensors
o Analysis and Simulation Techniques o Redundancy
• Rules and Guidelines for subsystem operations
o Operational Modes and Associated Procedures o Links to the Power Subsystem
o Ground Support Software
Derived / Calculated Parameters Configuration and Range Checks Pre-Pass, R/T and Post-Pass Operations
o Comparison of Different Missions
GEO Missions vs. LEO Missions Scientific vs. Commercial Missions
Past vs. Present Missions, and Future Trends
Repeater Subsystem Operations • Typical Layout
o Low Noise Amplifier o Down Converter
o Input Multiplexer (Demultiplexer) o High Power Amplifier
o Switching Matrix o Up Converter o Output Multiplexer
• Rules and Guidelines for subsystem operations
o Launch and Early Orbit Phase (LEOP)
No operations (Repeater is switched off)
o In Orbit Test (IOT) Phase
Initial Switch-on
Test all nominal and redundant equipment Test all pathways
Perform antenna mapping (Minimise the number of on-board switching and changes of configurations)
o On Orbit Control(OOC)
Routine control of the repeater configuration
Check-out of the correct position and attitude of the satellite by monitoring the link quality
Scientific Instruments Operations
Example: ROSAT low earth orbit
• Transmission of Telecommand (TC)
o High Power (HP) commands; Low Power (LP) commands
Power ON/OFF
o Single commands
Configuration of the Payload
o Time-Tagged (TT) commands
Low earth orbit
Contact times and scheduled payload activities
• Monitoring of Telemetry (TM)
o House Keeping Data checks (HK)
on ground (R/T, NRT, Off-line) within the instrument
or the S/C bus
o Failure Detection, Isolation and Recovery (FDIR)
Real-time check on board (normally S/C bus) for FDIR (example: CHAMP)
o Real-time Checks
during contacts for health monitoring
o Near-Real-time Checks
for monitoring data collected between two passes (quick-check)
o Offline Checks
done by the experimentator for decisions like 'replanning last task'
• Optional Interfaces
o Time Information, Time correlation (example: ROSAT)
o Keep alive or health signals for reactions within the experiment
o Request for power off within the S/C bus because of serious problems within
the experiment
• Operations
o Routine Operations
TT Ops (example: ROSAT)
Mission planning cycle (example: ROSAT)
o Long term planning o Short term planning
o Replanning (very short term)
Command Scheduling (example: ROSAT)
o Contingency operations; errors detected by HK data during contacts and
handled by:
Procedures by the Ops Team On-call by the engineers On-call by the payload experts
o Contingency Operations; errors detected by Science data and handled by:
Replanning of tasks Reprocessing of data
o Critical Phases:
Launch and Early Orbit Phase (LEOP) Commissioning Phase / In Orbit Test Phase Contingencies
o Documentation
o ICD Interface Control Document
Description for the exchange of data and information between control centre and payload experts
Distribution of tasks and responsibilities
o Requirements Documents
Collection of external requirements according (examples): Telecommand database
Number of commands per contact Number of TT’s per 24 hours Telemetry database
Number of TM Values
Planning; scheduling; orbit; contact times; attitude manoeuvre; constraints; data dumps
Interface S/C bus - Payload
o Spacecraft User Manual
Short overview (content)
On Console Training
• Familiarisation on Console
o Control Room Environment o Tools
• Intercom System and Voice Procedures
o Login Procedure o Configuration o Subsets • Telemetry System o Databases o TM Processor
o Alarms- / N/A- and N/S-flagging o Operator Inputs
• Command System
o Operational Modes/Uplink Patterns
o Verification Methods (BD/AD Modes, A priori/A posteriori Conditions)
• Rules and Guideline for Routine Operations
o Anomaly Processing o Logging and Reporting
o Procedures as the leading element in operations
o Scientific Missions and their pass profile (example: CHAMP) o Pre/Post Pass Activities
o Offline Tools
o GEO satellites and their profile
• Products and Sources
o Orbit o Schedule o Science
• Simulation with the following key positions (role models):
o Mission Operations Manager (MOS) o Command operator (CMD)
o Subsystem expert (e.g. TCR or PWR)
Two to three consoles involved Procedure for switching transponders Procedure for switching heaters
Ground Segment
Ground Station Networks
• Network Requirements and Characteristics
o Spacecraft Operability and Safety
Support Spacecraft with Telemetry and Command capability More than one station to allow longer contact periods with the spacecraft
Required Locations (depending on orbit characteristics) Get tracking information for orbit determination
High availability (Redundancy)
o Support of required Frequency Bands, Modulations and Spacecraft
characteristics
Downlink in KU-Band, S-Band, X-Band etc.
Support of the required Bandwidth (Uplink, Downlink) Different Uplink Modulations
Other Antenna characteristics required for Satellites in Low Earth, Transfer, Geostationary, or Deep Space Orbits
o Network examples
NASA Deep Space Network (Goldstone, Canberra, Madrid) NASA Polar Network (Poker Flat, Wallops, McMurdo, Svalbord) ESA, CNES Networks
Integrated DLR network (connecting different networks) Private Networks of Industry (LORAL, Hughes)
Ground Station Design • Tasks
o Telemetry o Telecommand o Tracking
o Terrain o Soil o RF-Interference • Main Components o Antenna o RF Equipment o Baseband Equipment
o Time and Standard Frequency Equipment o Station Computer Network
• Design Aspects o Link Budget o Antenna Size o G/T o EIRP o Pointing, Autotracking o Component Location
o Interface Antenna Site/Operations Building
• Electrical Power Supply
o Requirements and Availability o Public Power Supply
o Solutions for Non-Interrupted Supply
• Monitoring and Control
o Time Behaviour o Network Aspects
o Man Machine interface (MMI)
• Operational Aspects
o Routine Operations, LEOP Support o Operations Personnel
o Maintenance and Repair
Control Centre Functions • Communication Links
o Public carrier links (ISDN, Leased lines) o Private Satellite links (roof to roof) o Link usage
o Real-time data (Telemetry, Command)
o Offline data (Telemetry, Tracking data, Orbit information, SOEs) o Voice, Video
o Telex o Telephone
o Gateway functions for different user and communication protocols
• SCC Internal Communication
o Structure of the internal communication network LAN system
o Different network components and nodes (Routers, Gateways, Firewalls, Data
distribution and processing nodes)
o Network security concept
• Hardware Components
o Voice system o Video system o Telephone system o Consoles
o Power System o Printing and Xerox o Office Communication o Access Control and Security
o Internal Communication Equipment o External Communication Equipment
• Software Components
o Operating Systems (OPEN_VMS, NT, LINUX, UNIX) o Network Software (DECnet, TCP/IP)
o Archiving- and Retrieval systems (GDS-Log) o Data Distribution (Routing, Flow Control) o External Gateway Software (EDI)
o Process monitor- and control systems for ground equipment o Office Communication and Documentation
• Ground Station Network and SCC Mission Preparation
o SCC and Network Specification Phase o Detailed Design Phase
o Integration Phase o Testing and Verification
• Ground Station Network and Mission Execution Operational Aspects
o Station interface handling o Redundancy switching
o Software System Configuration o Pass Preparation
o Controlling (Discrepancy Reports) o Accounting
o Reporting o Scheduling