As of today, January 5th, anyone with a lapsed subscription to Star Trek Online will be allowed to log into the game and be considered a Silver Member. Cryptic Studios are giving those players who play, or have played in the past, an early entrance into the "free-to-play" version. That means that any account that had a subscription to Star Trek Online in the past, even just the first month, can come back and explore the galaxy free of charge!
For those of you who do not already know or are unfamiliar with the difference between being a Gold Member and Silver Player to Star Trek Online, it is whether you have a subscription or not. The Gold Member is a subscriber and pays monthly to play, whereas the Silver Player will be able to access many features of the online game without paying a cent.
As for the rest of the potential captains of Star Trek Online, the official free-to-play launch will be on January 17th. So, if you have never had a subscription to the MMORPG, you will have to wait just a little under two weeks.
Source: Game homepage