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Acronym for Search and Rescue. Raptors are used for SAR operations because of sufficient room for medics and life-support equipment.
Galactica rarely has opportunity for SAR operations to retrieve pilots after combat with Cylon forces in the Re-imagined Series, as they must retreat when the civilian Fleet retreats, forced to leave any surviving Viper pilots to die once their oxygen runs out, or worse, to the mercy of the Cylons.
Twice Galactica itself engaged the Cylons in battle as part of the rescue mission. This was necessary both times as the ship was required to draw off the Cylon forces while the rescue occurred. Pegasus participated in a similar rescue op once in the series as it was part rescue, part mission to destroy the Guardian Basestar.
List of SARs Conducted by battlestar Galactica