Surveyor Lander Simulator

This a simulation of the Surveyor Lunar Lander written in Rust, using the Bevy game engine. This is still a work-in-progress and actively in development. At the time of writing, the main entry-point into the program is in the surveyor-graphics crate.

The landing algorithm has not been implemented yet and sensor/actuator systems are currently being built up along with the guidance and control software.

The goal of this project is to build a generic simulator in Rust that can be run natively or on the web, and used for simulating real-life spacecraft guidance algorithms.

Building and Running

Native

cargo run

Web

Install trunk and run

trunk serve surveyor-graphics/index.html

Project Status

This is currently heavily under development and not in an MVP state yet. Expect breaking changes, force-pushes to master and overall mayhem. I may also go into hibernation for random periods of time if I get too busy at my day-job or other pursuits.

Current Features

Entity-Component-System (ECS) architecture
- Clear separation between the simulation (aka "truth-side") and the flight software
- uses bevy "Events" for communication between dfferent systems and between simulation and flight software
3D Graphics visualization using the bevy game engine
- Implemented in the surveyor-graphics crate
- Uses 3D meshes from Orbiter for the spacecraft
6DOF Spacecraft Simulation with Sensors and Actuators
- Implemented in the surveyor-physics crate
- Configurable using XML (investigating other options as well)
- RK4 fixed-step integrator (see surveyor-physics crate)
- 6DOF spacecraft dynamics w/ point-mass gravity model
  - Rudimentary collision detection (configurable) with planetary bodies
  - High-precision timing using the hifitime crate
  - Earth and Moon positions loaded from JPL ephemerides (de440s.bsp) using ANISE
- Actuator models
  - Reaction Control System (RCS)
  - Vernier Engines with Thrust Vector Control
- Sensor models (currently do not incorporate noise)
  - Bare-bones Gyroscope
  - Star Tracker that directly measures inertial attitude
  - Star Sensor (the original Surveyor had a Canopus star sensor)
- Interface between Simulation and Guidance software (surveyor-physics/src/interfaces/)
- Precise control of simulation update vs flight software update (w/ the former running at least 2x faster)
Flight Software (primarily just the Guidance, Navigation and Control aka GNC part)
- Implemented in the surveyor-gnc crate
- Three "Guidance Modes"
  - Idle
  - Detumble
  - Pointing (with a quaternion and/or body rate target)
- Sensor components that convert from sensor-frame to body-frame
  - IMU
  - Star Tracker
  - Star Sensor
- Actuator components that sends commands to the truth-side
  - RCS
  - Vernier engines w/ TVC
- Sensor Aggregator
  - Keeps track of all sensor data, their health and provides data persistence in case of sensor outage
- Attitude Estimator
  - Very simple component that directly passes through attitude data from the star tracker for now
- Attitude Controller
  - Simple PID controller that can track a body-rate or inertial quaternion target
- Control Allocator
  - Passes torque commands from the Attitude Controller to RCS
  - Will include commands to Thrust Vector system in the future
- RCS Controller
  - Allocates body-frame torque request to RCS thruster duty cycles based on thruster position and orientation

TODO:

Load planetary data (such as radius and gravity parameters) from SPICE kernel
Sun sensor simulation + GNC component
- Requires feeding in position of Sun from Ephemerides
Attitude estimator that uses Sun Sensor and Canopus Star Sensor to determine attitude
TVC/Vernier Engine Attitude Controller
Add particle effects/other visualization for RCS thrusters and vernier engines.
Add solid retro rocket system (truth-side and FSW) and implement stage-separation logic
Implement surveyor guidance algorithm from here and demonstrate