There never was an "Aurora" craft. That was one of the temporary names give to part of the budget for the B-2. It was mistakenly left in documents made public. That's what started the whole 'Aurora' thing. When a program is classified, a lasting name is never given to the craft... Only coded names for the various stages of development. There was a follow-on program to the SR-71, but it was not named Aurora and it was never finished. It was decided that having a manned vehicle like that was not necessary, with the advent of satellite technology.