Attention!
We’ve doubled our efforts to give Captains the necessary experience to deal with threats to the Galaxy. From Thursday, March 19th at 8AM PT, to Monday, March 23rd at 10AM PT, players will be able to enjoy twice the experience!
During the event, content that provides skill points and expertise will reward a 100% (2x) Bonus above normal amounts – this bonus will be available for all content that rewards skill points and expertise.
Source: https://www.arcgames.com/en/games/star-trek-online/news/detail/11390543-double-experience-weekend%21