Stargate Universe Season 1 Episode 18 (Stargate Universe s01e18) with title “Subversion” airs on Friday, May 21st 2010 at via.Syfy 09:00 pm
Here is summary for Stargate Universe Season 1 Episode 18 :

Earth’s Stargate Program isn’t the only group in the Milky Way that’s interested in the Ancients’ Destiny. What’s worse, this long-time foe may have a spy among those closest to the Icarus project.

Few hours after original series aired on TV, online streaming video for Stargate Universe Season 1 Episode 18usually available on Net and of course, if video available, as soon as possible will show you where you can watch this episode for free.