In 1969, the USAF issued a requirement for a replacement for the B-52
with a contract for research, development, test and evaluation awarded
to Rockwell and General Electric in 1970. The first B-1
in 1974. Four prototype
B-1s were built before President Carter
cancelled the B-1 program in 1977 in favor of cruise missiles.
President Reagan resumed the B-1 project in 1981 with a modified
aircraft designated the B-1B. The first production B-1B flew in
1985. The B-1 is also known as the "Bone".