Fuel

All landers rely on a specific type of fuel, and can carry a limited supply. Once their supply is exhausted, they will be unable to launch any further missions until refueled. Managing fuel usage and improving fuel consumption efficiency becomes increasingly important as you expand to more distant planets and moons. (Technically, artificial satellites also consume fuel. However, they carry enough that they are limited only by the maximum range that has been researched for them.)

## Fuel Types

**Chemical Fuel** is used for most Rockets and Satellites and is going to be used when you start out in the game. You can purchase more fuel at the shop furthermore you can craft this off-world to refuel your spaceships with 2 Carbon and 2 Water inside the Factory to be rewarded with 5 chemical fuel. You need a Re-usable Space craft to refuel as the Single-use space crafts can still refuel they will just be discarded once sent back to earth.

**Ion Fuel** is used for ion Satellites, and in spacecraft that have an ion engine modification added. There is currently no spaceship that uses Ion fuel as its primary fuel.

**Plasma Fuel** is used in fewer Rockets and Satellites but is a much more efficient fuel source and is used later in the game. You can purchase more fuel at the shop furthermore you can craft this off-world to refuel your spaceships. You need 5 Uranium ore to craft Refined Uranium inside the Uranium Refinement Facility then take the Refined Uranium and craft Plasma fuel to be rewarded with 5 plasma fuel. You need a Re-usable Space craft to refuel as the Single-use space crafts can still refuel they will just be discarded once sent back to earth.

## Planning Missions

When preparing to launch a craft, you can view a summary or itemisation of the projected fuel costs for the outward journey and potential direct return journey. These costs can include lifting off the surface, leaving orbit, leaving the influence of a nearby planet, travelling through space, and then similar costs in reverse for landing at the destination. They are strongly influenced by planetary mass, and also by the mass of the lander, with distance being a smaller but still important concern. The cheapest possible trip is travelling between different moons of the same planet, with minimal mass at the source moon and atmosphere available for aero-braking at the destination.

Note that when departing from Earth, you automatically purchase a booster rocket to lift the lander out of Earth's substantial gravity. The first rocket for each lander is included in its purchase price; thus, for single-use landers like the Moon Lander and Bullet Mk 1, it is a hidden cost. However, its effects can be seen when examining the fuel usage breakdown and seeing that an outward journey from Earth uses less fuel than a return journey. This is especially apparent with high-gravity destinations like Mars and Venus.

If a lander would not be able to directly return from its destination without refuelling, then the game will give a warning message, but still allow the launch. If there is no landing pad at the destination to assist in refuelling, it will give a second warning. ***Ignoring these warnings, without careful planning, may result in a lander being stranded at the destination***. Note that a bug currently permits single-use landers like Bullets to return to Earth regardless of fuel levels, so they cannot be stranded. This may change with future development.

If even a full fuel tank would not allow the lander to lift off, then the game will not allow the launch; you must either choose a more capable lander, or research better fuel efficiency. The exception is for unmanned supply craft, which have no need to return. Note that for reusable landers, this restriction applies only to the actual lift-off from the world; the rest of the return flight might still require more fuel than the lander can carry, but the game will not stop you from landing there (although it will give a warning about not being able to directly return).

## Research

There are several technologies that reduce the fuel usage of your landers. Researching them to a high level is a critical part of expanding your space program to more distant locations.

* Chemical Efficiency improves the efficiency of the Moon Lander, Bullet Mk 1 and 2, Dragon and Dragon Extended, Harpy Eagle, and the small and medium unmanned supply craft.
* Aerospike Propulsion improves the efficiency of the small and medium aerospike shuttles. Note that they still refuel with chemical fuel, but they do not benefit from Chemical Efficiency (due to their different engine design).
* Plasma Efficiency improves the efficiency of the Black Hawk.

## Refuelling

Landing on Earth automatically and immediately refuels a lander at no cost. Off-world refuelling requires additional setup:

* You can buy additional packs of chemical or plasma fuel on Earth, load them into a lander's cargo bay, and later use an astronaut to manually refuel the lander with them. Each chemical fuel pack provides 1 fuel, while each plasma fuel pack provides 5 fuel.
	+ This does not require any additional infrastructure, but does cost credits and take up cargo space.
* You can build a Landing Pad at the destination and send packs of plasma fuel (but *not* chemical fuel) to fill its tanks, then use workers to automatically refuel parked landers.
	+ This has the same cost, or more, but allows you to use up valuable plasma fuel in increments rather than consuming an entire pack at once, if you so desire.
* After building a Landing Pad, you can expand it with the Chemical Fuel Production module, and/or build a Factory. You can then craft chemical fuel (but *not* plasma fuel) from collected water and carbon, and fill the Landing Pad tank with that.
	+ Water and carbon have almost no market value and are plentiful on most worlds, so this option is more time-consuming but eventually allows you to refuel ships indefinitely at minimal ongoing cost.
	+ Crafted fuel cannot be loaded onto a lander as cargo nor used directly by astronauts.

Note that plasma fuel cannot be crafted, only purchased on Earth, (As of March 23 2023 you can now craft plasma fuel off-world with Refined Uranium) making the Black Hawk a powerful but expensive craft to operate. However, only a Black Hawk with high plasma efficiency can lift off from Venus. Future development may provide an option to craft plasma fuel from uranium.

## Strategy

Since refuelling on Earth is fast and free, it is generally easiest and safest to only make a single trip out to another world and then return, rather than flying around multiple destinations. This is particularly effective when using single-use landers, since they (currently) never need refuelling. With enough upgrades to the Bullet Mk 2, you could theoretically colonise the moons of Neptune without ever needing to build up any refuelling infrastructure.

Off-world refuelling is particularly expensive for heavy craft with large fuel tanks, like the Harpy Eagle and especially the Black Hawk. The Medium Aerospike Shuttle is generally a more economical choice, albeit with a higher build cost than the Harpy Eagle.

As you expand further away from Earth, it becomes increasingly important to consider the orbits of each planet, and when they are closer together, since that may lengthen or shorten a trip by up to 40 AUs, which has a significant impact on the number of refuelling stops needed. It may be wise to choose a single moon from each gas giant as a refuelling point, and ensure that each has sufficient Landing Pad upgrades (both in capacity and production) to handle the traffic, so that there will almost always be a refuelling point on the near side of the solar system. When approaching a planet from outside, all moons are treated as being equally distant, and travelling between neighbouring moons is typically very cheap, so only one high-level refuelling point should be needed for each planet.

Theoretically, a single refuelling point around Jupiter would suffice for most purposes, but it might involve a long wait for Jupiter to be on the nearer side of the solar system.