An orbital laser strike, as a mod for Horizon, the Rust rewrite of Minecraft Java. Pick a laser from a wheel, hold the Orbital Laser Designator on a target, and a strike comes down from orbit. It digs a crater and a shaft to bedrock, flattens what stands round it and leaves the land changed for good.

Download  ·  Getting started  ·  How it works

Contents: New in 0.5.2 · The lasers · Getting started · Set it up with an AI agent · How to play · If something goes wrong · Known gaps · Credits and licence

• Planet Killer, the seventh laser, on the wheel's second page and /orbital planetkiller. Seven towers grind up out of the land on the horizon and strike a ring of light in the sky with lightning. The ring fuses and fires a beam down, and the land domes up and bursts. It leaves a crater about 480 blocks across with a shaft to bedrock, a broken rim of thrown rock, chasms and charred land. Then the ring, crushed to a point, falls into the crater and bursts again. Its sounds are its own, and its explosion is modelled on measurements of a real one.
• Faster terrain. The Planet Killer writes its crater straight into the world's chunks through the fork's new world.edit-blocks, instead of thousands of commands, so there is far less stutter. Its land is done about 25 seconds into the strike.
• The wheel fits any window, down to the smallest GUI (320 × 240), with short blurbs and tidier spacing.
• Needs the next Orbital Laser build of Horizon, orbital-mod-api-4 (it adds world.edit-blocks). Older builds won't start the mod.

Earlier versions: docs/CHANGES.md.

Seven lasers, five on the wheel's first page and two on its second.

• Plasma. A raging beam with forked lightning. The crater fuses into glass, obsidian and magma, ringed in fire.
• Godly. The clouds part and a pillar of light comes down. The crater turns to quartz and gold, with flowers.
• Black Hole. A singularity opens over the target and bends the light round it. It tears the ground up into orbit, swallows it and drags the land into spiral arms.
• Meteor Storm. 72 meteors pound the land round the target, then one the size of a hill hits it: a crater about 125 blocks across.
• Mothership. A kilometre-long ship drops in over the target, drills a shaft to bedrock and cuts a molten trench with its beam. You pick where it comes in from, how it arrives and its colour.
• Downfall (page two). The Mothership again, but a meteor brings it down. It crashes into the land and buries itself, and then its black hole engine ruptures and swallows the wreck.
• Planet Killer (page two). Seven towers out on the horizon strike a ring in the sky with lightning, and its beam leaves a crater 480 blocks across.

Plasma, Godly, the Black Hole and the Meteor Storm reach 200 blocks; the Mothership, the Downfall and the Planet Killer reach 1000. How it works describes each one from start to finish.

The laser wheel	Plasma	What Godly leaves behind

Meteor Storm	The extinction impact	What it leaves

Mothership	Its underside	For scale, from 900 blocks

Downfall	The crash	The black hole

Planet Killer	The beam	The burst	The crater

1. Get the Orbital Laser build of Horizon (orbital-mod-api-4 or newer). Download horizon-orbital-linux-x86_64.tar.gz from Stink-O/horizon releases and unpack it to ~/horizon-orbital.

   It needs Horizon's prepared resources, made once from your own Minecraft 26.3 (Horizon's PLAY.txt explains the server jar and Java 25):

   cd ~/horizon-orbital
   ./horizon-prepare --prepare --server-jar PATH/TO/server.jar
   ./horizon-prepare sounds

   If you already have Horizon set up, skip that and point HORIZON_RESOURCES at its prepared resources (the folder .local/horizon-client/26.3 inside it).

2. Install the mod. Download orbital-laser-v0.5.2.zip from the latest release, unzip it, and with the game closed run:

   python3 install.py

   It copies the mod into Horizon's game folder (~/.local/share/horizon/horizon-mods/orbital, or $HORIZON_HOME) and switches it on. If 0.1's shader pack and sound pack are installed, it takes them out.

3. Play. From the same folder:

   ./play.sh                 # a creative test world called OrbitalTest
   ./play.sh MyWorld         # or one of yours (back it up first)

   It starts the Orbital Laser build on your normal game folder, so your worlds, settings and mods are all there.

4. In the game, type /orbital give for the Designator and the Remote.

If you use a coding agent (Claude Code, Codex, Cursor and the like), paste the message below into it and it can do the whole setup on your computer. AGENTS.md has the same guidance for agents that read the repository themselves.

Set up Orbital Laser on this computer and get a test strike working, end to end:
https://github.com/Stink-O/orbital-laser

It is a mod for Horizon, the Rust rewrite of Minecraft Java (https://github.com/ludovic111/horizon). It
runs on a Horizon fork that adds the mod capabilities it needs: https://github.com/Stink-O/horizon (branch
mod-api-input-ui-render-world, release orbital-mod-api-4 or newer, with a ready-built Linux x86-64
download on its releases page). When it works I can type /orbital give in the game, right-click the
Orbital Remote (or press R) to pick a laser from a wheel, and hold the Orbital Laser Designator on a
target to call down the strike.

Before doing anything, read these from the repository: README.md (especially "Getting started", "If
something goes wrong" and "Known gaps") and AGENTS.md.

Facts to rely on:
- Minecraft is not included, and you must not download, fake or work around it. Horizon's prepared
  resources come from my own copy of Minecraft Java 26.3 (horizon-prepare with the 26.3 server jar, as
  Horizon's PLAY.txt says). If I don't have Minecraft 26.3, stop and tell me.
- Stock Horizon can't run this mod: it needs the fork's build, orbital-mod-api-4 or newer. On Linux
  x86-64 use the release download. Elsewhere, build the fork from source (cargo build --release -p
  horizon-client --features mods, Rust 1.85 or newer) and tell me before you start, since it takes a while.
- This was developed and tested on Linux only. On Windows or macOS expect rough edges. Keep any fix small,
  and tell me exactly what you changed and why.
- install.py needs Python 3.8 or newer. If it's missing, ask me before installing anything.
- A real strike is destructive and permanent: a crater about 60 blocks across, a shaft down to bedrock, and
  every mob and dropped item within 40 blocks killed. The bigger lasers go much further: the Planet Killer
  flattens the land out to 340 blocks and digs a crater 480 across. Use a throwaway creative world (play.sh
  makes one called OrbitalTest), never one of my real worlds, and ask me before the first strike with
  terrain damage on. The wheel's centre button and `/orbital terrain off` turn terrain damage off.
- Run install.py with the game closed. Don't edit my saves or settings beyond what install.py does.

Steps:
1. Download and unpack the Orbital Laser build of Horizon to ~/horizon-orbital, and give it prepared
   resources (horizon-prepare, or HORIZON_RESOURCES pointing at an existing Horizon's
   .local/horizon-client/26.3).
2. Download the latest Orbital Laser release zip (or clone the repository), and run `python3 install.py`.
3. Run `./play.sh` and wait for the world to load. In the game: `/orbital give`, then `/orbital terrain off`.
4. Test safely first: press R and check the wheel opens and closes, then hold the designator on the ground
   for a second and check the strike plays with sound and nothing in chat. Ask me before a strike with
   terrain damage on.
5. Tell me how to use it: R or the remote for the wheel, hold the designator on a target to fire, and
   Options > Controls > Key Binds to rebind R.

Report each step's result as you go. If a step fails, show me the exact command and message, say what you
think is wrong, and fix it. Don't guess past a failure. If the mod shows as stopped on Options > Mods, read
the reason on its row first.

1. Type /orbital give for the Orbital Laser Designator and the Orbital Remote.
2. Pick a laser. Right-click with the remote, or press R, and the laser wheel opens. Point at a laser to read what it does and click to load it. The arrows either side of the ring, the tabs over it or a right-click turn the page. The middle switches terrain damage on or off, and Escape closes the wheel. Your choices are remembered.
3. Fire. Hold the designator, aim at a target and hold right-click for under a second. The action bar shows ACQUIRING TARGET…, then the strike lands where your crosshair is.

Only one strike runs at a time. Plasma, Godly and the Black Hole take about 26 seconds, the Planet Killer 30.5, the Mothership 34, the Meteor Storm 38 and the Downfall 64.

The wheel also has:

• FLY SPEED over the title, for getting round the craters: click along the bar for 1x to 40x vanilla's creative flight, or type any speed up to 1000x in the box beside it and press Enter.
• MESSAGES and PANEL switches, which turn off the strikes' messages over the hotbar and the status panel shown at the top right while you hold either item.
• For the Mothership and the Downfall, rows for where the ship comes in from, how it arrives, and its colour.

How it works has the full details of each command. To rebind R: Options → Controls → Key Binds, the Orbital Laser section at the bottom.

• No wheel, no /orbital command, or the items do nothing. You're running stock Horizon or an older fork build. Start the game with ./play.sh on orbital-mod-api-4 or newer. On Options → Mods, Orbital Laser's row says why if it stopped.
• play.sh can't find the build or the resources. Set HORIZON_ORBITAL to the folder with the build's horizon-client and horizon-ctl, and HORIZON_RESOURCES to the prepared resources.
• R does nothing. Something else may use R: check Options → Controls → Key Binds (a clash is shown in yellow) and rebind it. R only opens the wheel while you play, not over another screen.
• NO TARGET IN RANGE. You're aiming at the sky, too far, or at unloaded chunks. Past your render distance only the Mothership, the Downfall and the Planet Killer can aim, and only with LOD Distance on in Video Settings.
• STRIKE IN PROGRESS. One strike runs at a time. Wait for it to finish.
• No sound. Check the in-game master volume (Music & Sounds) and your system volume for the game.
• The shaft fills with water, or ends in obsidian. It hit groundwater, and the lava at the bottom met it.

• It needs a Horizon fork until Horizon adds these capabilities upstream. The ready-built fork is Linux x86-64 only.
• Linux only so far. Windows and macOS are untested.
• Single player (or hosting LAN). The world changes need a world the game itself runs, and the effects are drawn only for the player who fired.
• Terrain damage can't be undone. Back up the world, or switch terrain damage off.
• Targets must be in loaded chunks. The three long-range lasers reach 1000 blocks across the distant terrain, where the aim follows the coarser distant heights, and a crater only shows there once those chunks load.
• Stock Horizon builds from before 24 October 2026 can run 0.1's setup (Plasma and Godly only, driven from outside the game): see How it works.

To build the mod from source or change it, see CONTRIBUTING.md.

Orbital Laser is under the MIT License (LICENSE). Third-party notes are in NOTICE. It is built on Horizon by Ludovic and contributors (MIT), and the Orbital Laser build of Horizon is a fork of it.

Minecraft is a trademark and work of Mojang Studios and Microsoft. Orbital Laser is an independent fan project, not made by or affiliated with Mojang, Microsoft or Horizon's author, and it contains none of their code, textures or sounds. You need your own copy of Minecraft.