Ship reactor

A ship reactor is a ship part needed to take off. Activating the reactor causes 15 days of raids but must be done to launch, creating the primary challenge of the ship launch ending.

Acquisition

Ship reactors can be constructed once the starship reactor research project has been completed. Each requires 350 Steel, 280 Plasteel, 70 Uranium, 8 Advanced components, 65,000 ticks (18.06 mins) of work modified by the construction speed of the builder, and a construction skill of 8.

Once constructed, they cannot be re-installed, they can only be deconstructed.

Ship reactors cannot be built under a roof (though a roof can be constructed afterwards).

Summary

A ship reactor must be activated in order to launch a ship. The activation process takes 15 days, during which the colony will be attacked by many raids. The raids will stop once the reactor is fully activated, or if the reactor is destroyed. There does not need to be a completed ship in order to start activation; you can start as soon as the reactor is built. Activation requires no colonist interaction, and can be done even if the reactor/ship is inaccessible.

Otherwise, a ship reactor will provide 1000 W of power at all times, regardless of activation.

Analysis

For dealing with the 15 day period of raids, see Ship launch.

It's best to activate a reactor before building the rest of the ship. Doing more construction will increase your colony's wealth, increasing the strength of raids. This also gives you more flexibility in defending the reactor, as you can surround it with walls, making it a non-target for most raiders. After the raids are done you can build the rest of the ship at your leisure.

Power

As a power source, its cost and size make it extremely inefficient, even when nearing the endgame.

Geothermal generators are cheaper ( 340 Steel, 8 Components) and provide 3,600 W of constant power. Geothermal vents are finite, but 1-2 generators can power an entire colony for large portions of the game.
A chemfuel powered generator ( 100 Steel, 3 Components) provides a constant 1,000 W for 4.5 chemfuel per day ( 621 market value per year), can be placed practically anywhere, and only occupies a 2x2 region.
A battery plus two solar generators ( 270 steel, 8 components) can provide an estimated 1100 W all day (barring some events) at roughly 15% the cost.

In the extreme endgame, where you have an infinite amount of resources from deep drills or long-range mineral scanners, then ship reactors provide eternal, "free" power without space restrictions or any amount of colonist work. Also, reactors will never have their components breakdown.

If you're just trying to launch a ship, then there's no reason not to build a reactor whenever possible, and link it to your main power supply.

Version history

? - Recipe changed from 300, 500, 150, 25 -> 500, 500, 100, 20
Beta 19/1.0 Update - Reduced all costs to build the ship components by 30%. Recipe changed from 500, 500, 100, 20 -> 350, 280, 70, 8