Rocket Landing Simulator

A 2D rocket landing simulator built with Pygame and Pymunk. A fully autonomous autopilot launches the rocket, navigates it across to a moveable landing platform, and attempts a propulsive vertical landing - all driven by a Kalman-filtered state estimator and a multi-phase guidance controller.

---

Demo

Rocket_Sim_Demo.mp4

Autonomous rocket landing simulation - Kalman-filtered autopilot, multi-phase guidance controller

---

Features

• Autonomous autopilot - multi-phase flight controller (launch → ascent → coast → descent → terminal) handles the entire mission without any manual input
• Kalman state estimator - filters noisy telemetry for altitude, velocity, and attitude before passing it to the guidance logic
• Physics simulation - rigid-body dynamics and collision detection via Pymunk (2D Chipmunk wrapper)
• Moveable landing pad - drag the landing platform anywhere before launch; the autopilot recalculates its trajectory accordingly
• Live telemetry HUD - altitude, velocity, fuel, angle, and autopilot phase displayed in real time
• Pannable/zoomable viewport - scroll-wheel zoom, middle-mouse pan, toolbar zoom buttons
• Resizable window - layout adapts to any window size

---

Project Structure

├── main.py               # Entry point, game loop, rendering
├── rocket.py             # Rocket physics body, thrust, telemetry, drawing
├── autopilot.py          # Kalman estimator + multi-phase guidance controller
├── landing_platform.py   # Moveable landing pad - physics segment + drag gizmo
└── ui.py                 # SimControls, Toolbar, TelemetryHUD, AutopilotHUD

---

Requirements

• Python 3.8+
• Pygame - rendering and input
• Pymunk - 2D physics

Install dependencies:

pip install pygame pymunk

---

Running

python main.py

---

Controls

Placement mode (before launch)

Input	Action
Drag landing pad gizmo	Move landing pad (X / Y axes)
WASD	Nudge landing pad
Scroll wheel	Zoom in / out
Middle mouse drag	Pan camera
Enter	Launch

Simulation mode

Input	Action
R	Stop simulation, return to placement
Scroll wheel	Zoom in / out
Middle mouse drag	Pan camera
Escape	Quit

UI buttons on screen handle Simulate / Stop / Reset as well.

---

How the Autopilot Works

The autopilot runs a closed-loop guidance cycle every frame (autopilot.update(telemetry, dt)):

State estimation - raw telemetry (altitude, vx, vy, angle) is smoothed by four independent 1D Kalman filters before any control decisions are made.

Flight phases - the controller moves through phases in sequence, each with its own throttle and attitude targets:

Phase	Description
launch	Full thrust, slight lean toward the landing zone
ascent	Throttles to climb rate target, steers laterally
coast	Minimal thrust, lets apogee develop
descent	Throttles to a speed profile keyed to altitude
terminal	Fine lateral correction, bleeds speed to a soft touchdown

Attitude control - a PD controller computes a torque command from the angle error and angular rate at each phase, with phase-specific gains.

Throttle - vertical throttle is computed from the difference between a reference descent rate and the current vertical velocity, corrected for tilt angle, so thrust is always sufficient to counteract gravity along the vertical axis.

---

Key Constants

Defined at the top of each file -- easy to tune:

Constant	File	Default	Effect
ROCKET_MASS	rocket.py	5.0	Affects thrust-to-weight ratio
THRUST_FORCE	rocket.py	5600.0	Peak engine thrust
FUEL_CAPACITY	rocket.py	300.0	Total fuel units
FUEL_BURN	rocket.py	12.0	Fuel burn rate per second at full throttle
GROUND_Y	main.py	HEIGHT - 200	World ground level in pixels
FPS	main.py	60	Simulation frame rate