T-38A 70-1574, operated by the 6512th Test Squadron, 6510th Test Wing, Air Force Flight Test Center, Edwards AFB.
December 1983. Rather plain, The blue tail band with white Xs represents the 6510th Test Wing.
July 1984, Air Force Systems Command badge added to the tail.
February 1989. Tail codes added 1987/88, Air Force Flight Test Center badge added on the spine about the same time.
Thanks for looking,
Sven
Old Viper Tester