Jose wrote:

If you're trying to do reconnaissance of time-sensitive targets,
better a Mach 0.8 vehicle which can be launched with an hour's
notice rather than a Mach 3.0 vehicle which takes a full day to
prepare for launch.

...unless it's always ready for launch. Your tax dollars at work.

That's Bill's point. (And one of th things that scuttled the YF-12
Interceptor Blackbird) It's not a matter of topping up the fuel
tanks, cocking the airplane, and hooking up the start carts.
You've got to deal with stuff like keeping the TEB (Tri-Ethyl Borane -
spontaneously combusts in air, required to light off the low
volatility fuel in the engines & afterburners, and Really Nasty
Stuff) under control, and the hydraulic fluid heated (It ranges from
being a powder to something agin to Jello at normal temperatures)
Not to mention having the crew pre-breathed, suited up (Space Suits)
and ready.

Oh, yeah - you've also got to get the tankers to their rendeavous
points. The Blackbird may do its thing at Mach 3, but the tankers
get there a Mach 0.85, just like anybody else.

--
Pete Stickney
Java Man knew nothing about coffee.