Cleaning Together, Up to Sixteen at a Time

Quick answer

Moon Sweepers supports single-player and online co-op for up to 16 players. Money is shared, and since patch 1.0.3 the Upgrade Matrix is shared too — the host's levels apply to everyone and anyone's purchase upgrades the crew. Vehicles are still personal purchases. There is no crossplay and no split-screen.

How co-op works

One player hosts a save, others join the session. Everyone works in the same world, on the same Moon, with the same cleaned ground. Since 1.0.4 the ground synchronisation was reworked specifically because players used to see dust reappear where someone else had cleaned.

Shared money, shared upgrades

The economy is communal. When one player deposits dust, the crew earns. When one player buys an upgrade from the matrix, the crew gets it. This makes co-op dramatically more efficient than solo — but only if the crew stops thinking individually.

What changed in 1.0.3

Before the patch, brush capacity upgrades and matrix upgrades were personal. A player who bought a Wide Head got a wider brush; their crewmates did not. That created the odd situation where the person who cleaned least had the best equipment.

Now: the whole crew uses the host's upgrade matrix, anyone's purchase upgrades everyone, and older saves keep the highest level anyone had already bought.

What is still personal

• Vehicles. Each player buys their own. A crew of sixteen does not need sixteen Lunar Sweepers.
• Held tools. Your brush is yours, even though upgrades are shared.

Splitting sixteen people

Sixteen players all sweeping the same hex is worse than four players sweeping four hexes. The useful split is by capability, not by preference.

Ground crew (1–6)

Manual sweeping near the depot. They finish hexes, keep blue patches from accumulating, and feed the first Packager. This is the best role for new players because it teaches the loop.

Drivers (1–4)

Vehicles, distant regions, and flag or survey pickups along the way. Drivers should not be responsible for belts — they will be away from the base for long stretches.

Builders (1–3)

Belts, power, processing machines, and the unglamorous work of checking that capsules actually reach the depot. In a large crew this is the highest-leverage role.

Scouts (1–2)

Flags, surveys, station discovery and waypoints. Patch 1.0.4 added the teleport panel, which made scouting considerably more useful because discovered stations become fast-travel points.

Host controls and moderation

Patch 1.0.3 added host controls in the ESC menu. The Your Crew list shows everyone in the session, and the host can kick or ban a player. Banned players cannot rejoin that save unless the host unbans them from the same menu.

The host also owns the upgrade matrix, which since 1.0.3 means the host's progress defines the crew's baseline. Joining an experienced host is genuinely valuable.

Common multiplayer problems

Someone cannot join

1. Confirm both players are on the same game version.
2. Confirm the host's session is actually open, not a solo save.
3. Check whether the player was banned from that save.
4. Restart Steam if the lobby is not appearing at all.

Dust reappears where someone cleaned

This was a real bug before 1.0.4. Ground synchronisation was reworked in that patch so everyone sees the same cleaned ground, including robot trails and manual cleaning. If you are still seeing it, you are on an older build.

A crewmate's splitter or merger does nothing

Fixed in 1.0.3. Splitters and mergers built by crewmates now work, and since 1.0.4 any crewmate can place splitters and mergers on belts another player built. Before that, only the belt owner could edit it.

Performance drops with a big crew

1.0.3 improved frame rates by roughly 20% on large bases in the developers' tests, and 1.0.4 made saving large worlds nearly instant. If performance is still bad, the usual culprits are robot count and the size of the built-up base rather than player count.

Crew etiquette

• Ask before demolishing. Removal refunds less than the purchase price, and a deleted belt can stop an entire line.
• Do not hoard money. Shared upgrades mean the crew's money is most valuable spent immediately.
• Announce vehicle purchases. Two players buying Lunar Sweepers at once is 5,000 dollars that could have been a processing line.
• Leave the depot route alone during peak production. Rebuilding a main belt while three people are feeding it creates confusion that takes longer to untangle than to avoid.

Read the automation guide before taking the builder role, and the map guide before taking the scout role.