Complex sentence: Hughes had already won the MX-904 contract for a missile known as the GAR-1 Falcon, and this was selected for 201A mainly because it seemed to be the only one that could be ready in time to meet the 1954 operational date.
Split into simpler sentences: Hughes had already won the MX-904 contract for the missile GAR-1 Falcon. This was selected for 201A mainly because it seemed to be the only one that could meet the 1954 operational date.