ok, so i havent worked out a storyline for this, but pretty much there is a new race of NPCs. killing them rewards unusable artifacts (like chronshifter parts). there will be a temporary 'shop' where you can exchange these dropped artifacts to construct modules, buildings, and powerful artifacts.
For example, there can be 3 of each type of module (weapon, defense, cloak, scan, hull, shield, reactor) and there can be mkI, mkII, and mkIII. there can only be a set number of modules installed, and each tier requires more and more parts to build. BUT to keep it obtainable for lower levels, i think it should not increase exponentially, but rather linearly. like, for example
*Dark Matter Turret mkI- 3 broken shifters, 4 damages frames, 2 cracked capacitors
*Dark Matter Turret mkII- 6 broken shifters, 8 damaged frames, 4 cracked capacitors
*Dark Matter Turret mkIII-9 broken shifters, 12 damaged frames, 6 cracked capacitors.
As for buildings, i was thinking a similar market for mineral, artifact, research, and fusion buildings; with the better buildings costing more parts.
For the story i was thinking something along the lines of 'Due to a sanctioned weapon testing malfunction, the galactic military tore a temporary hole in our reality. Looks like the hole crosses over to an alternate dimension where ships are built to exist solely in dark matter (impossible, i kno, but its scifi). Our scientists can reverse engineer their technology to harness the extreme abundance of dark matter in our universe and utilize it to its fullest potential."
Event lasts 1-2 months (maybe around christmas, or maybe just as a side event to distract us from doing missions.
)