They wanted to continue with the Stargate verse with a new show. They thought it might be cool to offer a darker, more serious Stargate show but most people didn't like it.
Stargate SG-1, Stargate Atlantis, Stargate Universe.
Because the network decided to make it.
Stargate Universe was created on 2009-10-02.
Blockade - Stargate Universe - was created on 2011-05-02.
Gauntlet - Stargate Universe - was created on 2011-05-09.
Faith - Stargate Universe - was created on 2010-04-16.
Sabotage - Stargate Universe - was created on 2010-05-07.
Stargate Universe season 2 is currently airing on the SyFy channel. It has not been announced if Stargate Universe has been renewed for a third season.
Stargate Universe chronicles the adventures of an exploration team ~ see related link below .
After the fifth season of Stargate Atlantis was completed a movie was promised to finish the adventure but unfortunately it fell through and MGM decided not to make one. So the answer to your question is no Stargate Atlantis won`t be coming back now Stargate Universe has finished. :(
The last episode of Stargate: Universe was Season 2, episode 20, "Gauntlet."
Jason Momoa is not a regular Stargate Universe star.