Why We’re Worried About the SR-72 Darkstar

Key Points: This analysis argues Lockheed Martin’s proposed SR-72 “Darkstar” hypersonic aircraft, despite its Mach 6 speed, is a strategically flawed and costly “vanity project.”

-It contends the SR-72 is ill-suited for modern attritional warfare, lacking persistent capability compared to drones or bombers, while its speed doesn’t guarantee survival against advanced defenses and its massive heat signature compromises stealth. Furthermore, its potential use risks dangerous escalation.

-The author concludes the SR-72 diverts vital funds from more critical defense needs like the F-47, B-21, drones, and logistics, representing outdated thinking compared to practical hypersonic missile applications.

SR-72: Trouble At Mach 6

The SR-72 Darkstar is everything a defense futurist dreams of – fast, sleek, menacing, and built to fly into the belly of a Chinese A2/AD network before its contrails evaporate.

Lockheed Martin’s Skunk Works has teased it as a spiritual successor to the SR-71 Blackbird, an aircraft so fast during the Cold War that no missile ever caught it. But dreams cost money, and in the world of defense procurement, the SR-72 Darkstar isn’t just expensive – it’s strategically incoherent.

The SR-72 Darkstar Dream 

The aircraft is supposed to fly at Mach 6, rely on a turbine-based combined cycle engine, and serve both as a reconnaissance and strike platform. It would be optionally manned, nearly impossible to intercept, and, in theory, capable of slipping through enemy airspace before hostile radars have time to blink. But we don’t live in the world of theory – we live in a world of multipolarity, attrition warfare, and fiscal triage. And in that world, the SR-72 doesn’t make sense.

Lockheed Martin has already sunk hundreds of millions into early design work and engineering prototypes. As 19FortyFive recently reported, the company has been absorbing heavy losses on this program since 2022, with the expectation that future Air Force contracts will make up the difference.

That’s a dangerous assumption. The U.S. military already faces a procurement crunch, forced to balance the costs of sustaining the F-35 fleet, ramping up B-21 Raider production, and developing both NGAD and the F-47 – the latter meant to serve as a more survivable, attrition-resistant sixth-generation fighter.

In that context, the SR-72 Darkstar is a vanity project. It’s a Cold War throwback disguised as a revolution in airpower. And while the Pentagon is rarely immune to shiny objects, the strategic environment has changed far more than the aerospace industry has.

Speed is no longer the decisive variable in high-end conflict. During the Cold War, the SR-71 could outpace Soviet interceptors and surface-to-air missiles with sheer velocity. But today, a Mach 6 aircraft doesn’t guarantee survival. Hypersonic sensors and interceptors – like Russia’s S-500 or China’s expanding counter-space architecture – can detect and potentially engage even the fastest platforms. And then there’s the problem of thermal signature: a Mach 6 aircraft glows on infrared like a flare in a dark room.

Forget stealth – this thing would be lit up across half of Low Earth Orbit.

The Darkstar Has Problems

Even if it survives, the SR-72 has a second problem: it doesn’t loiter. In a Pacific war, where combat will stretch across weeks and months, the winning side will be the one that can stay in the fight. Drones can do that. Satellites can do that. Bombers with long legs and plenty of fuel can do that.

The SR-72 can’t. It’s built for sprints, not marathons. It can’t hold orbit over the Taiwan Strait waiting for a missile battery to blink. It can’t provide persistent ISR, electronic warfare, or battle damage assessment. What it can do is execute a few high-risk stabs deep into enemy territory – once or twice – before retreating to a hardened airbase and a maintenance crew with PhDs in materials science.

And this gets to the heart of the issue. The SR-72 is not built for the war we’re going to fight. It’s built for a war we want to avoid – a short, sharp, high-tech blitz in which speed, surprise, and precision decide the outcome in days. But that’s not how peer wars play out anymore. The future is attritional, defined by magazine depth, logistics, and redundancy. The Chinese aren’t going to fold because one hypersonic plane made it to Chongqing and back. If anything, that kind of platform tempts escalation.

If the SR-72 Darkstar is ever used to deliver kinetic strikes, it immediately blurs the line between ISR and first-strike capability. And let’s be blunt: a Mach 6 aircraft barreling toward China’s interior is going to look like a first strike, regardless of its payload.

No one in Beijing is going to calmly assume it’s just taking pictures. That’s how miscalculation becomes conflagration.

Meanwhile, the F-35 continues to bleed operational dollars, and the F-47 – meant to serve as a workhorse in a high-intensity, sensor-saturated battlespace – needs to be procured in numbers that allow for attrition, redundancy, and forward deployment. These are the real tools of deterrence: platforms that show up, stay put, and keep operating under fire. Not platinum-plated hypersonic jets that do little more than flash across radar screens and blow out budgets.

It’s not that hypersonic technology is irrelevant. It’s that hypersonic aircraft are the wrong platform for it. Hypersonic missiles already offer the ability to strike targets quickly, unpredictably, and at standoff range. Those weapons are small, mobile, and hard to track.

By contrast, the SR-72 is a large, fixed-base-dependent aircraft with a massive logistics footprint. In the opening phases of any war with China or Russia, airbases will be under immediate threat. We’ve already seen in Ukraine what modern missile and drone strikes can do to concentrated infrastructure. The SR-72 may never get off the ground.

And yet the allure persists. Because there’s something intoxicating about resurrecting the Blackbird for a new age – something that speaks to the mythos of American airpower. But myths don’t win wars. Logistics does. Resilience does. Platforms that can take a punch and stay in the fight do.

The SR-72 is none of those things. It is, at best, a niche capability built for a highly specific, high-risk mission set. At worst, it’s a budgetary sinkhole that tempts escalation, diverts resources, and delivers little in return.

Great for the Movies: Maybe We Don’t Need the SR-72 Afterall 

This is not a call to stop innovating. It’s a call to innovate where it matters. Swarming drones, autonomous ISR platforms, hardened command networks, and munitions stockpiles will win the next war. The SR-72? It might look good in a recruiting video or a Top Gun sequel, but it won’t change the outcome of a Pacific conflict or deter a Russian advance.

We don’t need another Blackbird. We need platforms that fly often, survive contact, and win ugly. The SR-72 may fly one day. It may even do so at Mach 6. But that doesn’t mean it should.

About the Author: Dr. Andrew Latham 

Andrew Latham is a non-resident fellow at Defense Priorities and a professor of international relations and political theory at Macalester College in Saint Paul, MN. Andrew is now a Contributing Editor to 19FortyFive, where he writes a daily column. You can follow him on X: @aakatham.