[MFAFF]

SR-71 is/was not obsolete....

'Withdrawn due to financial constraints and the increasing use of other information gathering methods'.

Use of fixed orbit satellites to replace a free flying aircraft...oopps..

Never mind, it wasn't missed a bit in Gulf War 1 or Afganistan but hey, you get more bucks to go elsewhere.

Airframe was limited by an inlet spike temp max of 427 degrees F.

Mach number may vary with height and outside air temp....

Sorry didn't read the second page.

Crickmore's book is 'one' of the bibles of the SRworld. But check out the SR71 Revealed by Rich Graha and his Tails and legends.
For great pics see Sled Driver and the Untouchables by Brian Shul.
Both are ex-SR pilots, as in operationally qualified drivers, not guests.

But th real winner is the SR-71 Pilots handbook, especially the second edition with additional performance information included.

As for Aurora, well is was linked to a successor to the SR but also to the AMB program which lead to the B-2 Spirit.
Which is correct remains to be seen.

I'd guess that it would not be impossible that the scramjet technology has been refined before and that the X-43 is a way of briniging it into the open, much like the use of the Blackbird by NASA in the 70s...