The Daedalus Variations

"The Daedalus Variations" is the fourth episode of the fifth season of Stargate Atlantis.

Summary
Colonel Sheppard's team finds the Earth ship Daedalus abandoned, adrift in space. The expedition knows that the Daedalus is currently at Earth, and decide to investigate. As McKay works to restore power, Teyla finds a recording in the computer -- the final entry of the ship's log.

It is Captain Sobol, apparently the commander of the Daedalus, who reports that equipment and supplies have been transported down to the planet's surface, where he and his crew hope to survive long enough to be found and rescued. Sobol plans to soon join them in an F-302 fighter.

The crew's predicament and the reason for their evacuation, however, is not the first question that Sheppard and the team have. The first question is ... Who is Captain Sobol?" They soon discover this ship is not the one they know, but a different ship that is jumping between various realities.

Update July 3, 2008

When a mysterious, duplicate Daedalus appears in orbit over Atlantis, the team is dispatched to investigate. Once aboard the deserted and severely damaged ship, the team discovers an ominous video message from the former captain. But before they can make sense of the situation, the ship is propelled into an alternate reality. As McKay tries to figure out what is going on, the ship continues to jump through various alternate realities, encountering an alien armada and the blistering heat of an expanding sun. Worse - the team realizes that if they don’t find a way back to their reality soon, they risk being lost forever.

Development

 * The script for "The Daedalus Variations", written by Alan McCullough was handed in on February 11, 2008, with further discussion regarding aspects of the episode on February 12.
 * Joseph Mallozzi's February 15th blog shows an image of an alien thermal grenade for use in this episode. Mallozzi's March 8th blog shows a blast door that is to be shown many times in the episode.
 * The actor playing Captain Sobol was casted on March 10, 2008.