Tranquilis beat me to it. I was going to say that the U-2 is now called the TR-1.
The satellite question was pretty well covered. On the one hand, they’re very good. On the other hand, it’s pretty hard to refuel them after you’ve been maneuvering them.
The biggest advantage of the SR-71 is that it can be put over virtually any place very quickly. But the important places are covered by sats, which can be over a spot more quickly than an SR-71; but they are somewhat predictable. The SR-71, however, requires a lot of resources. It needs a secure base with a long runway. They leak like seives on the ground. (Their titanium skin expands because of friction, so their tanks are sealed at operating speed.) They have to be refuelled immediately after takeoff. That means you nead tanker assets. They’re mainenance-intensive.
Global Hawks fly very high, have a loiter capability greater than a TR-1, and can be positioned over any place. Just not as quickly as an SR-71. They don’t require as complex an infrastructure as the Blackbird though, and can be launched from virtually anywhere. Plus there is no human inside of them to be killed or captured.
Dark Star was another concept. It was smaller than a Global Hawk, I think it was more stealthy, and it provided higher-resolution data. But it was dropped in favour of the Global Hank.
I think there may be situations where an SR-71 would be ideal, and in those cases it’s too bad we don’t still have them. (I’ll bet NASA would be accommodating with theirs if the CIA or Air Force asked to use them though.) It’s still… what? a 40-year-old design? Unlike the elderly B-52, we have other aircraft that can perform practically all of the same missions more cheaply and more efficiently.
MPSIMS: I was driving home from Edwards AFB one late afternoon. It was a dark day in the desert, with low black clouds and wind, and rain was threatening. As I drove westward on Ave. K, I saw an SR-71 flying low in the distance. He had taken off from Palmdale and had his burners on. The blue flame was as long as the airframe as it passed south-to-north and disappeared in the clouds.
I flew over Palmdale quite a bit when I lived in Lancaster and flew from Fox. It was neat to see the SR-71s sitting out on the ramp.