Complex sentence: The first NF-104A (USAF 56-0756) was accepted by the USAF on 1 October 1963 and quickly established a new unofficial altitude record of 118,860ft and surpassed this on 6 December 1963 by achieving an altitude of 120,800ft.
Split into simpler sentences: The first NF-104A (USAF 56-0756) was accepted by the USAF on 1 October 1963. It quickly established a new unofficial altitude record of 118,860ft and surpassed this on 6 December 1963 by achieving an altitude of 120,800ft.