Complex sentence: In 1959, recognizing the importance of the space-related mission, on 21 September 1959 the Air Technical Intelligence Center (ATIC) became the "Aerospace" Technical Intelligence Center.
Split into simpler sentences: In 1959, the Air Force renamed ATIC, recognizing the importance of the space-related mission. Instead of "Air" Technical Intelligence Center, on 21 September 1959 the unit became the "Aerospace" Technical Intelligence Center.