The Balls Eight is a NASA NB-52B Mothership, NASA tail number 52-008. It was retired from active service with NASA on 17 December 2004 after almost 50 years flying service. The Balls 8 was famous for dropping aerospace research vehicles for 106 flights of the X-15. It flew a total of 159 captive-carry and launch missions in support of the X-15 program from June 1959 to October 1968. It also flew missions supporting the X-24, HiMAT, Lifting Body vehicles, X-43, and numerous others.