Discovery mod is a full-scale expansion pack for Freelancer focused on continuing the story started in the vanilla campaign. The mod is used by some of the busiest multiplayer Freelancer servers and has multiplayer features including player owned (and built) bases, jumpdrives, cloaking devices and equipment manufacturing.
Discovery is a very expansive mod that adds a lot of end game value to freelancer, but it still has some flaws.
The universe is much larger and most of the added systems are of high quality. They have added an entire new house to the game, basically doing 1/5th the work the original freelancer devs did without the source code to make it easier.
They have done extensive work on the existing factions, expanding the rep grinding game to include guard factions such as Liberty Navy Guard (securing a positive rep with them, for example, is vital to patrolling the Alaska system).
Despite adding so many ships and systems, players still stick primarily to vanilla systems such as NY, Alpha, and Gamma. Most of the systems are perpetually empty.
Another issue is the totally static universe. The universe only gets updated when they release an update for the entire mod, so once you've explored a bit you pretty much have the gist of the mod for the next year.
Finally, the roleplay community can be extremely judgemental of any idea that does not perfectly fit into their well established, rigid, RP guidelines. This is annoying, since all the best ships and equipment can only be flown if you've joined that faction.
HHHmmmm...Discovery has over extended the delay on its 4.86 update by far too long, even when it does arrive once the new systems are explored it will soon become jaded and tedious again, a great shame for this once great mod, now populated online by mostly veteran players it is far too easy to beat the anti cheat and spoil the new guys fun there, hence the drop in players. Was great once, give it a miss unless you play offline only.