[equalsione]

At the risk of joining the tinfoil hat brigade, this is a 70 year old design. The sr 71 is retired and publicly there’s nothing like it. Has aircraft development regressed since the end of the Cold War or are there successors to these craft out there?

[semi-extrinsic]

What makes the U2 quite amazing is not just that it's a 70 year old design still in operation.

It's also that the U2 was developed by Lockheed Skunk Works on a $22.5 million contract, where they delivered 20 working aircraft in less than 2 years from project start and went $3.5 million under budget. They paid back the money. And as a bonus deliverable, the team also developed a new testing site with extra long paved runway, hangars, workshop etc. on a salt flat known as Area 51.

[ianhawes]

Presumably:

1. Satellites can now conduct imagery intelligence at a similar or higher quality without alerting targets, conducting refueling, or risking pilots.

2. There are more satellites with higher maneuverability than before.

3. Unmanned high altitude drones will replace the existing U-2S role in the next decade or so; or already have. Consider the U-2S role in the Chinese balloon incident. The military wanted intelligence on the balloon that would not otherwise come from a satellite and therefore utilized the U-2S.

[yabones]

To echo other commenters, it's simply because it's not needed as heavily anymore, and it's a very optimal design for the purpose.

Consider what satellite imagery was like six decades ago. The CORONA program used massive and complex satellites to take photos on film reels, then jettison and recover them using parachutes and catch them on a hook from an aircraft. Yes, really. Back then, it was much more effective to send a plane over and take some images manually.

Very soon after, even as early as the mid 70s, digital image processing and transmission made these obsolete with the launch of the KH-11 series. By this point, it was substantially faster, cheaper, and more reliable to use satellite imagery rather than spyplanes for general purpose surveillance.

The other thing to consider is the rise of surface to air missiles and air defense systems. These greatly changed the calculus of manned surveillance flights.

https://en.wikipedia.org/wiki/CORONA_(satellite)

https://en.wikipedia.org/wiki/KH-11_KENNEN

https://en.wikipedia.org/wiki/1960_U-2_incident

[Dennip]

IIRC The SR71 stopped being useful as a spy plane because missile defence improved to the point they could be shot down, and spy satellites took over the duties of reconnaissance.

These old airframes do get incremental upgrades to software/avionics/engines etc, and there is actually a SR-72 in development as a UAV.

[I_Am_Nous]

From what I've read, the SR-71 missile defense system was just to throttle up. Back when it was the fastest bird in the sky, this worked well, but we have supersonic missiles that can probably match its speed, and hypersonic missiles are even starting to be used in Ukraine.

[ceejayoz]

The MiG-31 largely stopped that approach from being viable. https://aviation.stackexchange.com/questions/16377/could-a-s...

[justin66]

The surveillance and EW electronics on the U-2 are kept up to date. You'd have to think long and hard about the value in developing an all-new successor to the airframe, rather than an incremental update to the U-2. The design is already very well suited to a very specific flight envelope. (as a practical matter, an all-new replacement made today targeting the "piloted and subsonic and fly as high as possible for a long time" would be required to have working stealth features and would be huge and cost a zillion dollars, and nobody involved wants to pay for that)

Regarding the aircraft comparison: the U-2 is surprisingly cheap to operate. It's brilliant. The SR-71 pretty much pegged the meter in terms of operating cost.

[lm28469]

It's like asking why rotary phones design stagnated since the 60s, we just don't have the use case anymore, we have better tools for the job

[ceejayoz]

Precisely; it's dead-end technology supplanted by satellites, drones, and stealth. Doesn't mean it wasn't incredibly useful in its prime, but we've got plenty of unclassified better stuff now.

[1001101]

I would say absence of evidence is not evidence of absence in this context.

[docandrew]

The X-37B seems like a likely candidate.

[aceofspades19]

It's more that this is close to the best design possible for this mission, it would take decades and lots of money to develop another aircraft that does the same thing that might not produce that much of an advantage. There are lots of designs that have been around for ages because they are effective and there is no reason to replace them. Even in the civilian world, there are lots of aircraft types that have been around for 50+ years because there is no real reason to get rid of them as long as they can be upgraded to the latest systems.

It's really only when an aircraft can no longer be upgraded or its mission no longer exists and can't be adapted easily for another one is when it's retired.

[hindsightbias]

Those aircraft were designed to maximally exploit the physical properties of statosphere via airfoils, gas turbines and materials science. There's no more there there other than more efficient turbines and materials which aren't really needed to accomplish the limited mission. Anything higher or faster would be less an aircraft and more a rocket so much more logical to jump the mesosphere and go straight to space.

[baseballdork]

I would say the F-22 and F-35 are _far_ more advanced than either the SR-71 or the U-2. I think spy planes have been made less critical and more vulnerable with advancements in spy satellites, drones, and air defense and so are not a focus of R&D.

[HumblyTossed]

Honestly, I think so. I think reliance on computers did it.

[newZWhoDis]

“Complex systems won’t survive the competency crisis”

[bee_rider]

Who are you quoting?

[itsyaboi]

Looks like someone by the name of Harold Robertson.

https://www.palladiummag.com/2023/06/01/complex-systems-wont...

[bee_rider]

I can see why somebody might not want to attribute that quote properly.

[Fnoord]

Why?

[bee_rider]

The piece puts the ideas of meritocracy and diversity in opposition in a way that I think lots of people would find objectionable.