The V29-321G (nicknamed Big Fat Fiery Fred) is a REPCONN Aerospace rocket.
The rocket was one of REPCONN's many abortive designs. It became infamous after an incident that destroyed the launch site, although the company responded optimistically, noting that an important lesson was learned in the creation of explosion-resistant shielding for both their rockets and their launch sites.
The V29-321G rocket appears in Fallout: New Vegas.
Behind the scenes
The nickname is likely a reference to the B-52 bomber, which was often referred to as the "Big Ugly Fat Fucker."