Science in Polaris Sector: Lumens has the same overall innovative scheme as in the base game, with research in Fundamental Sciences unlocking Applied Sciences through which new technologies are discovered.
However, in the base game, each race generally follows the same path through the science tree (apart from any special techs that they’ve chosen during setup). In Lumens, each of the races has different tech trees that both move around the existing technologies to emphasis the race’s different approach to life and also add new sciences and technologies!
For instance, rather than the core Fundamental Science of Biology, the Erians study Entelechy (a parallel, but bespoke philosophical theory on the basis of life). This then feeds into different Applied Sciences than, say, the Humans. Similarly, whilst most races still study Xenobiology to unlock important early habitation techs like the Marine Farm, some races instead study Xenovitalism and unlock this much later on, forcing those races to focus on Earthlike planets to feed their early settlers.
Additionally, the starting point of each race is different, with some races having more Applied Sciences unlocked at the start and with many having different starting technologies available. Extreme examples are that one races has no Applied Sciences unlocked at the start at all, whereas two others have the blueprints for Cruisers unlocked at the start (though it is a challenge to power these beasts with only basic technologies!).
Different races also have variations on the standard ship components. For example, whilst most races retain the Nuclear Reactor as their basic power source, some have the Stellar Core reactor which is more powerful but also much larger! Similarly, there are new variants for weaponry, with some early ships fielding the larger ranged Impulse Laser and/or the new Fireball Emitter.
Finally, there are new defensive fittings and offensive ship weapons included in the Lumens DLC. Examples include the EMP Missile that can temporarily disable enemy ships, Torpedoes that release blasts of gamma-rays upon detonation and new high level armour such as the Lumen’s active Svalinn armour.