Research stations allow you to combine 3 to 5 items into a new item. These items must be within one rarity of each other (petty/common is fine, common/uncommon is fine, but petty/common/uncommon is not) but do not need to all be of the same type or material.
The item type and material of the new output item is randomly selected from the input items. For example: combining an iron chaingun, titanium laser, and naonite railgun could you give any combination of those materials and item types.
The rarity of the output item is also randomly selected from the input items but then has a chance to be increased by one rarity level. The probability of this increase is 20% per input item provided, meaning that 5 items of the same rarity guarantee an output item of the next rarity.
Tech level of output turrets is calculated based on the tech level of the input items and then weighted towards the tech level of the research station. In this way, researching items with low tech levels at a research station with a high tech level can produce new items with higher tech levels and correspondingly higher stats. Together with Turret Factories, research stations within a radial distance of 3 are one of the ways to potentially create very powerful turrets at a tech level of 52.
Any research station can exchange 3 legendary modules (ship modules, not weapons!) for the XSTN-II quest artifact. A maximum of 1 out of 3 modules exchanged can be a XSTN artifact.
When combining items to increase rarity, researching items 3 at a time optimizes overall yield. This unintuitive conclusion arises because upgrade "failures" still give you an output item that can be used in future attempts.
- Combining 300 items of the same rarity 5 at a time, there's a 100% (guaranteed) chance of getting 60 items with upgraded rarity
- Combining 300 items of the same rarity 3 at a time, each of 100 attempts has a 60% chance of success -- meaning an average of 60 upgraded items.
- BUT: the expected 40 failures each return a new input item, translating to 13 new attempts, about 8 more successfully upgraded items, and about 5 more returned input items.
Ultimately, combining items three at a time will give you an average of about 7 upgraded items per 30 input items.
This higher overall yield comes at the cost of unpredictability, however, so caution should be exercised when combining items that would be particularly painful to collect again for future attempts.
Research stations will buy the following goods