Research is how new weapons, ship sections, salvage research, independent race studies and empire wide technology is discovered. You will only be able to Research a single item or a single Feasibility Study at any one time, but can also split your research among various special projects and your main tech research.
There is a set of Core Technologies that are available in every game.
The remaining technologies available throughout the technology forest are randomly checked at game creation to see if each such technology will be available during the subsequent play through. One check is made for every path that links to a particular technology.
Technologies that are not available in your current technology forest due to this randomization are still technically achievable, through surveys, random events, or salvaging it from another Faction.
Certain Faction specific technologies are only available to those Factions and will thus not appear in your technology forest unless you are playing that Faction.
The overall technology forest consists of multiple technology trees represented by the links below.
For an "at a glance" list of all the technologies in the game, please see the Technology page.
Sword of the Stars 2 starts off in the Fusion era, so Fusion power plants will be available from the beginning. Other beginning technologies include Cruisers, Plasma Cannons, UV Lasers, Green Beamers, Mass Drivers up to large, Station building and a few other things.
From the start of the game you are able to assign spending to Research and choose which technology will be focused on next.
Links between technologies in the technology forest are represented in the game as follows:
- Thin Blue Links — represent available Feasibility Studies from known technologies to possibly available technologies
- Thicker Orange Links — represent available Research choices from known technologies to available technologies
- Thicker Green Links — represent completed Research choices
At any point after starting research on a particular technology, you can cease research on that technology and switch to another. Any funding already placed into researching that technology will be briefly retained, along with the progress made. Subsequent turns without further investigation into that technology will result in the progress being lost piecemeal, requiring that the funding is replenished or, in extreme cases, restarted from scratch.
Science Stations with Modules dedicated to that branch of technology will slow the decline of such halted research, but will not stop it completely.
Similarly to SotS Prime, the game will start rolling for successful completion of the research once your Faction has accumulated 50% of the required funding for that technology.
At 101% of the required funding, it is considered that the research has gone over budget.
At 150% of the required funding, you will obtain the technology if the randomised technology forest created for your Faction at the start of the game included a successful roll for the technology.
At 200% of the required funding, you will be told that the research project has failed.
Some Races are better at research than others. The following races get the listed racial research modifier on all research: 
- Liir-Zuul: +50% bonus
- Morrigi: +20% bonus
- Suulka Horde: -10% penalty
Hiver, Human and Tarkas have no racial research bonus or penalty.
A new layer has been added to research, representing the uncertainty that a specific technology is in the technology forest or not for the current game. In SotS Prime, you could easily identify that certain technologies were unavailable to you by knowing which parts of the tree to reach for first, representing a benefit for longer term players of the game that knew the tree well.
Non-core technologies are now linked within the technology forest regardless of whether or not the randomization roll was successful for obtaining each technology this game.
There is no initial way to tell if a link to a technology is really feasible or not, and thus you will be telling your scientists to do a "feasibility study" on each non-core technology, where they can come back and say "We can get this technology pretty easily" or "We're not too sure about this one". These responses become your clues on how successful you might be at researching each project.
Be warned that as a result, it is now possible to spend time and money researching projects which are not immediately available. If your feasibility study says you have zero chance at the technology, you might not want to direct your scientists' efforts towards researching that technology unless you have nothing else for them to do.
The amount of time a feasibility study takes is based on the area of research, the number of dedicated laboratories, and the relative level of the tech. Lancers will take longer than X-Ray Lasers for example.
One advantage of having these links in the technology forest is that it makes it easier to see if you have the prerequisites for salvaging any techs that are not immediately available after doing the feasibility study. This change reflects both the uncertainty of the randomised tech forest and outlines for newer players where they might find certain technologies in every game, rather than just in those in which they successfully roll for the techs.
There will be a way to have a second chance to do a feasibility study (not implemented as of R18864b). The chances for this will depend on the amount of exposure to examples of the technologies, such as having plenty of repair/salvage ships able to analyze enemies with that technology. 
A feasibility study returns the odds of a tech give or take the TechFeasibilityDeviation percentage Modifier and also a unknown modifier based on if the tech is actually there or not.  If the technology is researched then the current research budget is converted to Research Points towards the completion of that technology project.
Note that the odds of success returned by the feasibility study are independent of the chances of the link being created at the start of the game. If a faction has a 75% chance of obtaining a link to particular technology in their forest, then they may expect to have access to that technology in 3 out of 4 games. It does not mean that their feasibility study for that tech is rated higher. The modifier from the first paragraph only occurs if the 75% chance succeeded at game creation.
The cost of the feasibility study seems to be around 10% of the research cost of the technology.
Please see the Salvage page for more information.
Science Stations specialize in certain fields of study. For example, a Science Station with dedicated Energy Weapons Laboratories will collect and collate everything that you know about energy weapons while you are playing the game. 
With regards to Salvage, the more science laboratories dedicated to the discipline a technology is in, the more efficiently random information is saved for a future date. The amount of accumulated Salvage data will be a factor in deciding if a special breakthrough project appears for an otherwise unavailable technology.