KSP Launch & Booster Recovery System

A comprehensive kOS autopilot system for Kerbal Space Program featuring automated gravity turn launches and SpaceX-style booster recovery.

Features

• 🚀 Automated Gravity Turn - Smooth, efficient ascent to orbit
• 🎯 Asparagus Staging - Automatic fuel monitoring and staging
• 🛬 RTLS Booster Recovery - SpaceX-style return-to-launch-site landing
• 🎮 Full Autonomy - Set it and forget it
• 📊 Multi-Booster Support - Handles multiple boosters with automatic spacing

Quick Start

1. Load your rocket on the launchpad
2. Open kOS terminal
3. Stage once to activate engines
4. Run: RUN 0:/launch.

System Architecture

Main Scripts

• launch.ks - Main launch autopilot (runs on main vessel)
• autoland_staging.ks - Booster landing autopilot (runs on each booster)

Libraries

• lib/util.ks - Utilities, math, LATLNG functions
• lib/guidance.ks - Trajectory prediction & impact calculation
• lib/ascent.ks - Gravity turn & staging logic
• lib/circularize.ks - Orbital circularization
• lib/boostback.ks - RTLS boostback guidance
• lib/entry.ks - Entry burn & descent control
• lib/landing.ks - Suicide burn & touchdown

Testing

• test_system_logged.ks - Comprehensive system test with file logging
• test_debug.ks - Debug script for troubleshooting

Requirements

Main Vessel

• kOS processor (10000+ bytes recommended)
• Proper staging configuration

Recoverable Boosters

Each booster must have:

• ✅ Probe core or command pod
• ✅ kOS processor (5000+ bytes)
• ✅ At least one throttleable engine
• ✅ Landing legs
• ✅ Power source (battery/RTG)
• ✅ Reaction wheel or RCS

Optional (Recommended)

• Airbrakes for descent control
• RCS thrusters for precise steering
• Grid fins

Configuration

Edit parameters at the top of launch.ks:

SET TARGET_APOAPSIS TO 100000.       // Target orbit (meters)
SET TURN_START_ALTITUDE TO 100.      // Start gravity turn
SET TURN_END_ALTITUDE TO 45000.      // Complete turn
SET TURN_SHAPE TO 0.5.               // Turn profile (0.4-0.6)
SET STAGE_FUEL_THRESHOLD TO 5.       // Stage at 5% fuel

Edit booster landing parameters in autoland_staging.ks:

SET SUICIDE_MARGIN TO 1.20.          // 20% safety margin
SET BOOSTBACK_MAX_BURN_TIME TO 60.   // Max RTLS burn time
SET LANDING_OFFSET_SPACING TO 10.    // Booster separation (meters)

How It Works

Launch Sequence

1. Vertical Ascent (0-100m) - Full throttle climb
2. Gravity Turn (100m-45km) - Gradual pitch over
3. Asparagus Staging - Automatic when fuel <5%
4. Coast to Apoapsis - Engines cut at target altitude
5. Circularization - Burn at apoapsis for circular orbit

Booster Recovery Sequence

Each booster independently executes:

1. Post-Separation Coast (2-3s) - Clear main rocket
2. Flip Maneuver (5-10s) - Rotate to retrograde
3. Boostback Burn (0-60s) - Return to KSC trajectory
4. Coast to Entry - Ballistic arc with airbrakes
5. Entry Burn (optional) - If speed >800 m/s at 15km
6. Descent - Retrograde orientation, calculate suicide burn
7. Suicide Burn - Adaptive throttle for soft touchdown
8. Touchdown - Land at <2 m/s vertical speed

Booster Spacing

Boosters automatically space themselves:

• Booster 1: -10m west of target
• Booster 2: Center (0m)
• Booster 3: +10m east of target
• Booster 4+: Pattern continues

Testing

Run the system test before first launch:

RUN 0:/test_system_logged.

Check test_results.txt for detailed output.

Troubleshooting

Boosters land short of target

• Increase BOOSTBACK_MAX_BURN_TIME (try 90)
• Decrease BOOSTBACK_TARGET_ERROR (try 300)

Boosters land long (overshoot)

• Decrease BOOSTBACK_MAX_BURN_TIME (try 45)
• Increase BOOSTBACK_TARGET_ERROR (try 700)

Landing too hard

• Increase SUICIDE_MARGIN (try 1.25-1.30)
• Check TWR >1.5 required for safe landing

Landing too soft (wasting fuel)

• Decrease SUICIDE_MARGIN (try 1.15)

Gravity turn too aggressive

• Increase TURN_END_ALTITUDE (try 50000-55000)
• Increase TURN_SHAPE (try 0.6)

Reference Documentation

• KERBOSCRIPT_REFERENCE.md - Complete kOS language reference
• README_LAUNCH_SYSTEM.md - Detailed system documentation

Credits

Based on research from:

• chippydip's suicide burn algorithm
• Patrykz94's kOS-RTLS-Landing
• kOS community documentation

Version

KSP Version: 1.12.5 kOS Version: 1.4.0+ Last Updated: 2025-03-22

License

Free to use and modify. Attribution appreciated.

Happy launching! 🚀