The C-133 had large tail doors and side doors and a large, open cargo area. The C-133A carried many large and heavy loads, including Atlas and Titan ICBMs, although it was not designed specifically to transport ICBMs. It may, indeed, have been the reverse. The C-133 design was frozen by 1955 in order to build the airplanes that first flew in April 1956. The designs of both the Atlas and Titan were not firm until after 1955, when their contracts were signed. With the C-133B, the rear cargo doors were modified to open to the side (petal doors), making ICBM loading much easier. Air transporting the ballistic missiles such as the Atlas, Titan and Minuteman was much less expensive, safer and faster than road transport. Several hundred Minuteman and other ICBMs were airlifted to and from their operational bases by C-133s. The C-133 also transported Atlas, Saturn and Titan rockets to Cape Canaveral for use as launch boosters in the Gemini, Mercury and Apollo space programs. After the Apollo capsules splashed down, they were airlifted in C-133s from Naval Station Norfolk, Virginia, or Hickam AFB, Hawaii, to Ellington AFB, Texas, or to California.