LibreSpaceflight Specification

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LibreSpaceflight Specification

Democratizing the Science of Space

Specification

LibreSpaceflight shall be an open-source, modular spaceflight simulation and research platform designed to make the science, engineering, and operational concepts of spaceflight accessible to students, educators, developers, researchers, engineers, and enthusiasts.

The platform shall provide a unified simulation environment for spacecraft rendezvous, docking, orbital mechanics, mission planning, spacecraft engineering, autonomous navigation, robotics, space operations, scientific experimentation, and educational training.

The system shall use a modular architecture in which core modules provide the fundamental capabilities of the platform and optional plugin modules extend those capabilities without requiring changes to the core simulation engine.

Core Module: Simulation Engine

The Simulation Engine shall provide the fundamental computational environment for spaceflight simulation.

Features shall include:

Newtonian orbital mechanics
Relative motion modeling
Multi-body gravitational modeling
Gravitational perturbations
J2 perturbation modeling
Atmospheric drag
Solar radiation pressure
Microgravity simulation
Time acceleration and deceleration
Simulation pause and resume
Deterministic simulation modes
Configurable simulation precision
Numerical integration methods
Collision detection
Physical object modeling
Mass and inertia calculations
Center of mass calculations
Force and torque modeling
Environmental parameter control

The engine shall support different levels of simulation fidelity so users can select simplified educational models or more advanced research-oriented models.

Core Module: Spacecraft Dynamics

The Spacecraft Dynamics module shall simulate spacecraft movement and physical behavior.

Features shall include:

Six-degree-of-freedom spacecraft movement
Translational motion
Rotational motion
Attitude control
Reaction control systems
Main propulsion
Thruster vectoring
Fuel consumption
Propellant depletion
Mass changes during flight
Thrust limitations
Thruster response characteristics
Momentum and angular velocity modeling
Spacecraft inertia
Center of mass changes
Structural response to maneuvering

Core Module: Rendezvous and Docking

The Rendezvous and Docking module shall provide detailed simulation of spacecraft approach and docking operations.

Features shall include:

Orbital rendezvous
Relative navigation
Approach trajectories
Closing velocity monitoring
Docking port alignment
Approach corridor visualization
Relative attitude control
Soft capture simulation
Hard capture simulation
Docking constraints
Docking tolerances
Rotating target docking
Tumbling target docking
Multi-ship rendezvous
Formation flying
Docking failure detection
Docking abort procedures
Precision docking scoring

The module shall support manual, assisted, and autonomous docking operations.

Core Module: Mission Planning

The Mission Planning module shall provide tools for designing and evaluating spaceflight missions.

Features shall include:

Mission objective definition
Orbital transfer planning
Hohmann transfer calculations
Phasing orbit calculations
Rendezvous planning
Launch window analysis
Delta-V budgeting
Maneuver planning
Burn scheduling
Fuel budgeting
Trajectory visualization
Mission timeline creation
Mission constraint management
Contingency planning
Mission success criteria

Mission plans shall be exportable and reusable as simulation scenarios.

Core Module: Navigation

The Navigation module shall provide spacecraft position, velocity, orientation, and relative-navigation capabilities.

Features shall include:

Absolute navigation
Relative navigation
Position estimation
Velocity estimation
Attitude estimation
Target tracking
Sensor fusion
Navigation uncertainty modeling
Navigation error modeling
Navigation updates
Communication delay simulation
Navigation failure scenarios

Core Module: Sensor Simulation

The Sensor Simulation module shall reproduce spacecraft navigation and docking sensor behavior.

Supported sensor types shall include:

Star trackers
Inertial measurement units
Radar
LIDAR
Optical navigation cameras
Docking cameras
Range sensors
Relative velocity sensors
Simulated satellite navigation

Features shall include:

Sensor noise
Measurement uncertainty
Sensor bias
Sensor drift
Occlusion
Sensor degradation
Sensor failure
Intermittent measurements
Sensor fusion experimentation

Core Module: Guidance, Navigation, and Control

The GNC module shall provide systems for controlling spacecraft movement and attitude.

Features shall include:

Manual control
Assisted control
PID controllers
Model predictive control
Attitude control
Translational control
Approach control
Docking control
Automated maneuver execution
Control response analysis
Controller tuning
Stability analysis
Control failure simulation

Core Module: Spacecraft Designer

The Spacecraft Designer shall allow users to create configurable spacecraft for simulation.

Features shall include:

Modular spacecraft construction
Component placement
Docking port configuration
Thruster placement
Propellant tank configuration
Power system configuration
Sensor placement
Communications equipment
Payload configuration
Mass distribution
Center of mass visualization
Inertia calculations
Thrust vector analysis
Spacecraft compatibility validation

The designer shall support reusable spacecraft configurations.

Core Module: Spacecraft Systems

The Spacecraft Systems module shall simulate major spacecraft subsystems.

Supported systems shall include:

Propulsion
Power
Communications
Thermal control
Guidance
Navigation
Control
Payload systems
Life support where enabled

The module shall support subsystem states, resource consumption, degradation, and failure conditions.

Core Module: Mission Control

The Mission Control module shall provide ground-based mission monitoring and operational control.

Features shall include:

Telemetry monitoring
Mission status displays
Command management
Command sequencing
Maneuver planning
Communications simulation
Communication delays
Mission timeline monitoring
Anomaly detection
Emergency procedures
Mission logging
Ground operator workflows

Mission Control shall support scenarios involving multiple operators and spacecraft.

Core Module: Telemetry and Data

The Telemetry module shall collect and process simulation data.

Features shall include:

Real-time telemetry
Historical telemetry
Flight event logging
Sensor data logging
Propulsion data
Navigation data
Docking data
Mission events
Failure events
Performance metrics
Replay data

Supported export formats shall include CSV, JSON, HDF5, and other research-compatible formats through extensible data adapters.

Core Module: Replay and Analysis

The Replay and Analysis module shall allow users to examine completed simulations.

Features shall include:

Mission replay
Time scrubbing
Multiple camera perspectives
Telemetry overlays
Event markers
Maneuver visualization
Docking analysis
Fuel analysis
Navigation error analysis
Control performance analysis
Failure analysis
Annotation tools
Comparative mission analysis

Core Module: Scenario Engine

The Scenario Engine shall provide a standardized framework for creating simulation scenarios.

Scenarios shall support:

Mission objectives
Starting conditions
Spacecraft configurations
Target configurations
Orbital parameters
Environmental conditions
Time limits
Fuel limits
Failure conditions
Success conditions
Scoring criteria
Mission events
Difficulty levels

Scenarios shall be shareable and reusable.

Core Module: Spaceflight Goals

The Spaceflight Goals module shall provide mission-oriented objectives.

Supported goals shall include:

Safe rendezvous
Precision docking
Fuel-efficient docking
Time-critical docking
Autonomous docking
Multi-spacecraft coordination
Satellite servicing
Space station assembly
Cargo delivery
Emergency rescue
Orbital debris removal
Scientific observation
Asteroid operations
Interplanetary navigation
Planetary landing
Mission recovery
Long-duration mission planning

Core Module: Education and Training

The Education and Training module shall provide structured learning experiences.

Features shall include:

Beginner tutorials
Guided docking procedures
Orbital mechanics lessons
Interactive explanations
Progressive difficulty
Mission objectives
Training checkpoints
Performance scoring
Instructor-defined scenarios
Student performance tracking
Mission reports
Replay-based instruction

The module shall support classroom, self-directed, and laboratory-based learning.

Core Module: Research Environment

The Research Environment shall support scientific and engineering experimentation.

Features shall include:

Batch simulations
Parameter sweeps
Monte Carlo simulations
Experimental configurations
Algorithm comparisons
Statistical analysis
Telemetry collection
Repeatable experiments
Research dataset generation
Simulation result comparison
Experiment metadata
Reproducibility support

Core Module: Visualization

The Visualization module shall provide interactive representations of the simulation.

Features shall include:

Three-dimensional spacecraft visualization
Cockpit views
External camera views
Orbital trajectories
Relative motion displays
Docking alignment indicators
Telemetry displays
Mission timelines
Sensor visualization
Spacecraft system status
Navigation displays
Mission Control displays

Core Module: Accessibility and Interface

The platform shall provide configurable interfaces suitable for different users and experience levels.

Supported controls shall include:

Keyboard
Mouse
Gamepad
Joystick
HOTAS systems
Configurable control schemes

Interface features shall include:

Adjustable HUDs
Configurable telemetry
Tutorial overlays
Accessibility settings
Simulation difficulty controls
Units selection
Display scaling
Input remapping

Core Module: Multiplayer and Collaboration

The Multiplayer module shall support collaborative spaceflight operations.

Features shall include:

Multiple spacecraft
Cooperative docking
Mission Control operators
Shared mission scenarios
Real-time telemetry
Collaborative mission planning
Spectator mode
Competitive mission challenges
Session recording

Core Module: Historical Missions

The Historical Missions module shall provide educational recreations of historical spaceflight operations.

Supported mission categories may include:

Apollo-era docking operations
Shuttle operations
Shuttle-Mir operations
International Space Station assembly
Commercial crew docking
Satellite servicing missions

Historical scenarios shall clearly distinguish educational simulation from official mission software or operational systems.

Core Module: Real Orbital Data

The Real Orbital Data module shall support integration of publicly available orbital information.

Features shall include:

TLE data
Satellite orbital parameters
Historical orbital data
Realistic ISS scenarios
Satellite tracking scenarios
Orbital data import
Data validation

External data sources shall remain optional and shall not be required for the core simulator.

Core Module: Space Traffic Management

The Space Traffic Management module shall simulate increasingly crowded orbital environments.

Features shall include:

Multiple satellite populations
Orbital traffic
Conjunction detection
Collision risk analysis
Avoidance maneuver planning
Traffic alerts
Automated warning systems
Spacecraft coordination

Core Module: Space Robotics

The Space Robotics module shall support robotic spacecraft operations.

Features shall include:

Robotic arm simulation
Robotic capture
Module movement
Satellite inspection
Satellite servicing
Orbital construction
Robotic docking assistance
Robotic manipulation

Core Module: Orbital Construction

The Orbital Construction module shall support assembly and construction missions.

Features shall include:

Modular station assembly
Habitat construction
Solar array installation
Docking adapter installation
Orbital shipyard scenarios
Multi-spacecraft construction
Robotic construction operations

Core Module: Satellite Servicing

The Satellite Servicing module shall provide scenarios involving active servicing of spacecraft.

Features shall include:

Inspection
Capture
Refueling
Component replacement
Solar array repair
Attitude stabilization
Servicing of cooperative spacecraft
Servicing of damaged or uncontrolled spacecraft

Core Module: Orbital Debris

The Orbital Debris module shall support debris management and removal scenarios.

Features shall include:

Debris population modeling
Debris tracking
Collision risk
Capture operations
Controlled deorbit planning
Debris mitigation scenarios

Core Module: Interplanetary Navigation

The Interplanetary Navigation module shall extend simulation beyond Earth orbit.

Features shall include:

Heliocentric trajectories
Interplanetary transfers
Transfer windows
Gravity assists
Multi-body dynamics
Long-duration mission planning
Deep-space navigation

Core Module: Planetary Operations

The Planetary Operations module shall support operations around and on planetary bodies.

Features shall include:

Lunar operations
Mars operations
Planetary descent
Landing guidance
Terrain hazard detection
Surface mission planning
Launch and ascent scenarios

Core Module: Asteroid Operations

The Asteroid Operations module shall support missions involving small bodies.

Features shall include:

Low-gravity dynamics
Asteroid rendezvous
Station keeping
Surface proximity operations
Anchoring scenarios
Sample collection
Sample return
Mining simulations

Core Module: Space Weather

The Space Weather module shall provide configurable environmental conditions.

Features shall include:

Solar activity
Radiation events
Solar storms
Navigation interference
Communications disruption
Spacecraft system impacts

Core Module: Scientific Payloads

The Scientific Payload module shall support space-based research missions.

Supported payload types shall include:

Telescopes
Earth observation instruments
Mapping systems
Particle detectors
Scientific sensors
Experimental instruments

Core Module: Crew Operations

The Crew Operations module shall provide optional human factors simulation.

Features shall include:

Crew roles
Workload
Fatigue
Task scheduling
Mission responsibilities
Crew coordination
Emergency response

Core Module: Mission Economy

The Mission Economy module shall provide optional economic simulation.

Features shall include:

Mission budgets
Launch costs
Fuel costs
Cargo contracts
Resupply missions
Resource management
Mission profitability
Commercial space operations

Core Module: Procedural Missions

The Procedural Mission module shall generate dynamic mission scenarios.

Generated scenarios may include:

Emergency docking
Rescue missions
Satellite interception
Damaged station repair
Cargo delivery
Debris removal
Asteroid rendezvous
Scientific missions

Mission generation shall support configurable difficulty, objectives, environmental conditions, and constraints.

Core Module: AI Mission Director

The AI Mission Director shall provide optional intelligent mission generation and training assistance.

Features shall include:

Dynamic mission generation
Difficulty adjustment
Training recommendations
Performance analysis
Scenario adaptation
Mission objective generation

Core Module: Autonomous Docking Benchmark

The platform shall provide a standardized environment for autonomous docking research.

Benchmark capabilities shall include:

Standardized docking scenarios
Controller evaluation
Reinforcement learning evaluation
Classical control evaluation
Hybrid controller evaluation
Performance metrics
Fuel efficiency metrics
Docking accuracy metrics
Failure rate analysis
Repeatability testing

Benchmark results shall be exportable for research and comparison.

Core Module: Open Spacecraft Database

The platform shall provide a structured reference system for spacecraft information.

Records may include:

Spacecraft mass
Propulsion characteristics
Docking configuration
Power characteristics
Sensor capabilities
Operational limitations
Mission role
Historical information

Data shall be clearly identified as authoritative, modeled, estimated, or community supplied.

Core Module: Digital Twin Framework

The Digital Twin framework shall provide an extensible foundation for representing real spacecraft and systems in simulation.

Features shall include:

Configurable spacecraft models
Telemetry mapping
System state modeling
Component models
Sensor models
Mission-specific configurations
Simulation comparison

Digital twins shall be clearly identified as simulations and shall not imply operational certification.

Core Module: Hardware Interface

The Hardware Interface module shall support external simulation hardware.

Supported categories may include:

Flight controls
Joysticks
HOTAS systems
VR devices
Motion platforms
Robotics interfaces

Hardware integration shall remain optional and shall not be required for normal operation.

Optional Plugin Modules

LibreSpaceflight shall support optional plugins that extend the core platform without requiring every user to install every capability.

Plugin: Advanced Physics

Provides additional high-fidelity physics models, numerical methods, and specialized orbital mechanics capabilities.

Plugin: Reinforcement Learning

Provides environments, interfaces, training utilities, and evaluation tools for reinforcement learning spacecraft agents.

Plugin: Genetic Optimization

Provides evolutionary optimization for trajectory planning, controller tuning, spacecraft configurations, and mission planning.

Plugin: AI Coaching

Provides intelligent analysis of user performance and recommendations for improving docking, navigation, and mission execution.

Plugin: Mission Generator

Provides advanced procedural generation of missions, objectives, environmental conditions, failures, and mission constraints.

Plugin: VR and AR

Provides immersive cockpit, visualization, and training interfaces for compatible hardware.

Plugin: Robotics

Provides advanced robotic arm simulation, manipulation, capture, servicing, and construction capabilities.

Plugin: EVA

Provides external crew activity simulation, astronaut movement, equipment installation, inspection, and repair scenarios.

Plugin: Crew Systems

Provides expanded human factors, workload, fatigue, crew scheduling, and multi-role mission operations.

Plugin: Space Weather

Provides advanced solar, radiation, and space weather event models.

Plugin: Real-Time Orbital Data

Provides integrations for compatible public orbital data sources and satellite tracking services.

Plugin: Historical Mission Pack

Provides additional historically inspired scenarios and mission configurations.

Plugin: Planetary Environments

Provides additional planetary terrain, atmospheric, gravitational, and operational environments.

Plugin: Asteroid Generator

Provides procedural asteroid generation and customizable small-body environments.

Plugin: Scientific Payloads

Provides additional scientific instruments, observation systems, and experimental mission capabilities.

Plugin: Multiplayer

Provides expanded networked simulation, collaborative mission operations, competitive scenarios, and spectator capabilities.

Plugin: Mission Control

Provides advanced ground control interfaces, operator stations, telemetry consoles, and mission command systems.

Plugin: Economy

Provides commercial mission planning, contracts, budgets, resource management, and economic simulation.

Plugin: Classroom

Provides instructor tools, student management, assignments, grading metrics, and educational mission packages.

Plugin: Research Suite

Provides advanced batch simulation, Monte Carlo analysis, parameter sweeps, experiment management, and research data workflows.

Plugin: Digital Twin

Provides advanced real-world spacecraft modeling and telemetry mapping capabilities for research and educational digital twin applications.

Plugin: Hardware Integration

Provides interfaces for specialized physical controls, robotics equipment, motion systems, and simulation hardware.

Plugin: Open Telemetry Network

Provides shared telemetry feeds, public mission monitoring, live mission dashboards, and spectator systems.

Plugin: Governance and Space Policy

Provides educational scenarios involving orbital coordination, debris mitigation, spectrum conflicts, mission regulations, and space governance.

Plugin Architecture

Plugins shall:

Be independently installable
Have clearly defined interfaces
Declare dependencies
Declare supported LibreSpaceflight versions
Avoid modifying core modules directly
Provide documentation
Provide tests appropriate to their functionality
Identify their own licensing requirements
Clearly distinguish optional dependencies from required dependencies

The plugin system shall allow new capabilities to evolve independently while maintaining a stable core simulation environment.

Community Mission Library

The platform shall support a community-driven library of:

Training missions
Research scenarios
Historical recreations
Spacecraft configurations
Space station configurations
Autonomous docking challenges
Orbital mechanics exercises
Scientific experiments

Community content shall identify its author, licensing terms, source data, and any external dependencies where applicable.

Development Principles

LibreSpaceflight development shall prioritize:

Open-source collaboration
Scientific transparency
Reproducibility
Modular architecture
Interoperability
Extensibility
Local-first simulation where practical
Vendor independence
Human oversight
Educational accessibility
Research utility
Clear documentation

Project Goals

LibreSpaceflight shall pursue the following long-term goals:

Democratize access to spaceflight simulation
Make orbital mechanics easier to learn
Provide an open platform for autonomous spacecraft research
Support aerospace education
Encourage collaborative spaceflight development
Create open benchmarks for spacecraft autonomy
Support reproducible spaceflight research
Encourage experimentation with spacecraft design
Provide accessible mission planning tools
Expand public participation in space science

Specification Branding License (SBL)

Standard

Fully AGPL-3.0+ compliant system
Copyleft enforced for network deployments
Required attribution:
- Roxanne Ardary
- https://www.roxanneardary.com/

Optional

Specification Branding License (SBL)
- Attribution-free commercial deployment
- Pricing based on scale, usage, and deployment scope
- https://roxanneardary.com/librespaceflight/

License & Notice Requirements

LibreSpaceflight is released under the GNU Affero General Public License v3.0 or later (AGPL-3.0+).
By contributing to this project, you agree that your contributions will also be released under this license.

Please note the following:

All contributions must comply with the AGPL-3.0+ terms.
Under Section 7 of the license, all redistributions, forks, and derivative works must preserve attribution to:
Roxanne Ardary and roxanneardary.com.
LibreSpaceflight specifications are free to use with attribution. A Specification Branding License can be negotiated upon request.
The project’s notice.md file tracks attribution requirements and contributor acknowledgments.
Any update that adds new contributors or modifies attribution should also update notice.md.
When submitting a pull request, ensure that any new files maintain the attribution headers where applicable.
Network-deployed versions of this software must also remain fully AGPL-3.0+ compliant, including exposure of source code modifications when applicable under the license.

For full legal details, please refer to the AGPL-3.0+ license and the project’s notice.md file.

Notice – LibreSpaceflight

Attribution Requirement: Under Section 7 of the AGPL 3.0+ license, all redistributions, forks, and derivative works, including network-deployed versions of this project, must provide attribution to Roxanne Ardary and roxanneardary.com.

Contributors

This file tracks contributors and their specific contributions to the project.

Roxanne Ardary, roxanneardary.com – March 11, 2026
Created the repository for LibreSpaceflight. Developed the open-source simulation platform for spacecraft docking, orbital mechanics, mission planning, and autonomous space operations.
[Add other contributors here] – [Date]
[Describe contribution in one sentence]

License – LibreSpaceflight

This repository is licensed under the GNU Affero General Public License v3.0 or later (AGPL-3.0+).

Key Points:

You are free to use, modify, and distribute the code.
All redistributions, forks, and derivative works or network-deployed versions must also be licensed under AGPL-3.0+ and provide attribution to Roxanne Ardary and roxanneardary.com as required under Section 7 of the license.
The software is provided “as is,” without warranty of any kind.

For the full license text, see GNU AGPL-3.0 License.