Viper 7242 is a Viper Mk. II spacefighter, which was apparently the favored craft of Bill "Husker" Adama during much of the Cylon War. It was found "rusting out in a salvage yard on Sagittaron" by CPO Galen Tyrol, who restored it to operational condition and presented it as a token of thanks to his retiring commanding officer.
The fighter was flown by Adama's son, Lee "Apollo" Adama, in a flyby performance during Galactica's decomissioning. The younger Adama was then assigned to escort Colonial Heavy 798 back to Caprica. It was during this time that the final Cylon Attack began without warning. Apollo was well-served by this craft's antiquated systems, which proved impervious to Cylon infiltration attempts, and was able to protect Colonial Heavy 798 and its passenger, Laura Roslin, long enough for them to gather a sizeable refugee fleet and rendezvous with Galactica at Ragnar Anchorage.
At the subsequent Battle of Ragnar Anchorage, Apollo commanded Galactica's defensive screen from the fighter. The ship sustained major damage to its engine assembly, but was returned the Galactica's hangar by the timely intervention of Kara "Starbuck" Thrace.
The damage to 7242 was repaired amidst the constant Cylon attacks during the first week after Ragnar. (33)
--Notes--
When 7242 is presented to Adama, is has the serial number N7242C. However, later in the Mini-Series, it is shown to be 7242NC in the format used by all the other Vipers. (Mini-Series)