Rocket

A Rocket is a multi-module building used to travel from the asteroid base to destinations on the Starmap and return with resources, data, or passengers. Every rocket requires an engine at its base, a Command Capsule at the top, and a Gantry that provides duplicant access to the Command Capsule. Rockets are assembled from vertically stacked modules; modules may be added, removed, or replaced while the rocket exists so long as each module is vertically connected (directly or via other modules) to an engine. Rockets return to the exact tile where they were constructed, carrying any cargo and Data Banks gathered during the expedition.

Engines determine the rocket’s range, exhaust behavior, fuel requirements, and heat output. The game contains four main engines: Steam Engine, Petroleum Engine, Biodiesel Engine, and Hydrogen Engine. Steam Engines are the entry-level option and use Steam as fuel, do not need external fuel tanks, and have a default range of 10,000 km without solid fuel thrusters. Petroleum and Hydrogen Engines use liquid propellants and require separate Liquid Fuel Tanks (and oxidizer tanks where applicable); Hydrogen Engines offer the best range but require extremely cold conditions to produce Liquid Hydrogen. Solid Fuel Thrusters can be added (they require their own gantry) to increase range. Engine exhaust has two components during launch and landing: an element emitted at a specific temperature directly under the engine (Steam or Carbon Dioxide depending on engine) and a heating effect applied across a 3×9 rectangle beneath the rocket that raises the heat of tiles/gases/liquids up to a specified maximum. Exhaust temperatures and heating rates vary by engine type; sustained launches/landings can melt even high-melting-point materials unless the launch area is properly managed or the rocket is built in space.

Command Capsules are always installed at the top of a rocket and are where a piloting duplicant enters. Before a launch the Command Capsule verifies multiple conditions: the rocket has fuel (Steam Engines have built-in tanks), a destination within the rocket’s range is selected, a duplicant with the Rocket Piloting skill is assigned and manning the capsule, the capsule contains an Atmo Suit, all Cargo Bays are empty, and the selected destination has sufficient resources for the installed cargo bays. When conditions are satisfied the Command Capsule outputs a green automation signal; receiving a start signal begins the launch. Rockets slowly accelerate to a top speed of 10 cells/s when launching and decelerate when landing; taller rockets accelerate more slowly.

Cargo Bays retrieve materials from destinations and are the usual way to bring resources back. Solid, Liquid, Gas, and Biological Cargo Bays return one ton of the respective phase on a successful expedition (Biological Cargo Bays return multiple small items like seeds or critters when available). All cargo modules weigh 2 t and have 1 t capacity (Biological Cargo Bays store multiple items). Research Modules, Sight-Seeing Modules and other utility modules perform non-transport functions: Research Modules unlock information about a destination and yield 50 data units on first analysis (future missions yield less), while Sight-Seeing Modules allow passengers to ride and reduce stress. Research and Sight-Seeing modules are much lighter—about 200 kg—and are often used to stack many small modules rather than fewer heavy cargo bays when range is limited.

Practical notes and strategies:

• Rocket mass strongly affects range. Unnecessary modules reduce how far a rocket can reach; replace sets of small modules with a cargo bay when mass budget favors cargo. Ten small modules (~200 kg each) are roughly equivalent in mass to one cargo module (2 t).
• Rocket modules are processed from top to bottom when determining returns. Place Research Modules above Cargo Bays if you want discovered rare resources to be loaded and returned on the same launch.
• Engines and solid boosters have a width of 7 cells; other modules are 5 cells wide. Side building tiles can block launches even if a gantry or ladder doesn’t.
• Engines must be built on solid ground but the ground can be removed afterward; rockets will still launch and land in midair.
• Rockets do not require full tanks to launch, but all fuel and oxidizer loaded will be consumed during a flight. Matching fuel/oxidizer to the desired range is fuel-efficient; third-party calculators (e.g., Professor Oakshell’s Rocket Calculator) are useful for planning exact fuel loads.
• Launch and landing generate intense localized heat. Building rockets inside insulated towers or in space reduces heat transfer into the base; the heat can also be harnessed (for example, to power Steam Turbines or process materials) if managed correctly.
• Returning rockets land at their original construction spot; use Space Scanners to detect incoming rockets and automate bunker doors to avoid collisions or damage. Extended Gantries and closed bunker doors are vulnerable to rocket damage during takeoff/landing.
• Refueling throughput differs: Liquid Fuel Tanks and Liquid Oxidizer Tanks can be refilled faster via liquid pumps than Steam Engines or built-in tanks via gas pumps due to input pipe limits. Plan refueling infrastructure to match launch cadence.

Rockets can be customized with any number of modules, but range, heat management, and available piloting/atmo-suit logistics determine effective rocket designs.