The Enigmatic SR-72 And the Palmdale Sightings: What Do They Tell Us About America’s Secret Hypersonic Program?

Oct 12 2017 - 29 Comments
By Tom Demerly

The Media is Full of Speculation, But What Do We Know and What Can We Predict?

One of 2017’s biggest defense and aviation stories is the anonymous sighting by a “handful of witnesses” of the landing of a mysterious, unidentified new aircraft at U.S. Air Force Plant 42 Production Flight Test Facility in Palmdale California. What was it?

Aviation Week reporter Guy Norris scooped the story but was guarded in his reporting of sources. On September 27, 2017 Norris wrote:

“According to information provided to Aviation Week, one such technology demonstrator, believed to be an unmanned subscale aircraft, was observed flying into the U.S. Air Force’s Plant 42 at Palmdale, where Skunk Works is headquartered. The vehicle, which was noted landing in the early hours at an unspecified date in late July, was seen with two T-38 escorts. Lockheed Martin declined to comment directly on the sighting.”

U.S. Air Force Plant 42 Production Test Flight Facility at Palmdale, California as seen from the air in an early photo. (Photo: USAF)

Nearly every article quoting Norris’ story suggests that, what the unnamed witnesses saw is related to a new global intelligence, surveillance, reconnaissance (ISR) gathering asset. Likely a new hypersonic remotely piloted aircraft (RPA) that could be a sub-scale developmental testbed for a planned manned version. While it is a significant leap to extrapolate this sighting to a full-scale manned platform, the silence from Lockheed Martin about the incident is deafening. Had the sighting been nothing, they would have said it was nothing.

It isn’t much of a leap to suggest that any proposed, new manned aircraft, colloquially referred to in most media as the “SR-72” would have global range, fly in excess of Mach 6, be low-observable and potentially have strike capability. This is one list of requirements for an SR-71 follow-on.

The U.S. Air Force Plant 42 Production Test Flight Facility at Palmdale, California with static display SR-71s and F-117s. (Photo: USAF)

When analyzing the role of a possible new strategic reconnaissance/strike asset, manned and unmanned, a few assumptions can reasonably be made. The mission of a high-speed reconnaissance (and possibly even strike) platform likely includes four unique capabilities for the strategic ISR and global strike mission:

1. It is very low observable. The relevance and quality of any intelligence collected is degraded substantially if the adversary knows it has been collected. A stealthy, ultra-high-speed intelligence gathering and strike asset could obtain signals, atmospheric and image intelligence across several spectrums potentially without detection. This improves the actionable relevance of the intelligence since the adversary does not know their operational security has been compromised.

2. It is timely. An ultra-high speed (some reports suggest Mach 6+) asset could be over the reconnaissance target area quickly and provide either real-time intelligence via secure datalink or be back on the ground quickly for retrieval and analysis of intelligence gathered over the target and stored onboard the asset.

3. It is difficult to intercept if detected. One of the primary defensive capabilities of the Mach 3+ SR-71 was its speed and altitude performance. It could outrun and out-climb most missiles and interceptor aircraft. But advances in detection, tactics, aircraft, aircraft weapons and surface to air missiles and even soon-to-be fielded focused energy beam weapons (as from the Chinese) provide a requirement for a faster, higher flying and lower observable platform.

4. It provides on-board decision-making capability in the manned configuration. While a manned asset exposes a flight crew to the risks associated with overflight it also keeps the human decision-making capability inside the mission loop. While this may not be critical in the ISR role, it may be in the strategic strike role. Once strategic strike platforms such as ICBMs and cruise missiles are committed to the attack they can be difficult to re-task or abort, especially in a dynamic tactical environment. A manned strategic strike asset with ultra-high-speed and global range retains a human in the decision loop. This is attractive both empirically and morally.

Having identified these four potential unique capabilities to a presumptive “SR-72” type asset it is appropriate to examine the possible regions and roles the asset would be employed in. Given the current and near-future strategic situation these four global missions may be part of the SR-72s tasking:

1. North Korea. The crisis has reached a near flashpoint with Pyongyang’s repeated missile and nuclear proliferation and continued adversarial rhetoric. Accurate and timely monitoring of North Korea’s actual testing activity and developmental capabilities is critical to managing the U.S. response in the crisis. This includes preventing the crisis from becoming an armed conflict. A strategic reconnaissance asset that is stealthy, fast and field-able would bolster the U.S. position in intelligence gathering, especially in this dynamic environment. A similar low observable, hypersonic strike asset would also be critical in maintaining our first strike capability should the rapidly evolving situation warrant it.

2. Iran. With potential changes in the U.S. doctrine and Iran’s nuclear policy maintaining real-time intelligence on Iran’s nuclear program is critical. The political environment surrounding Iran, and its attendant diplomatic ramifications, dictate that the best intelligence on Iran’s nuclear program and any weapons development be gathered covertly and updated in a timely manner. While orbital reconnaissance assets can provide excellent imaging across the entire spectrum from visible to infra-red to electronic emissions a reconnaissance satellite cannot collect atmospheric samples that are key to detecting nuclear testing. Also, re-tasking spy satellites not already in position with orbits over key targets makes a more dynamic, high-speed, low-observable atmospheric reconnaissance platform desirable.

3. Syria. The tenuous relationship with Russia in the Syrian conflict has been well-managed to date, but the potential for serious incidents still exists. Intelligence gathered covertly in real or near real-time about both Syrian and Russian activities in the region can help manage each participants’ agendas while lowering the risk of fratricide and other accidental conflict. It can also provide exclusive intelligence to the United States unavailable to other participating nations, providing a strategic intelligence advantage in the conflict.

4. The emerging global theater. The United States enjoys a geographic separation from the major Asian, African and Middle Eastern conflict areas. The geographic separation from conflict zones afforded by the Atlantic and Pacific oceans has been a significant reason for the U.S. ability to maintain security and prevent a large-scale conflict on U.S. soil. But this geographical distance from conflict zones also means preemptively managing conflict globally. It requires long reach and high-speed for timely intelligence gathering. A new high-speed, low-observable ISR/strike platform is required to maintain that agenda. This is a persistent requirement within the U.S. arsenal and will remain indefinitely.

Global conflicts thousands of miles from the U.S. dictate the continued need for stealthy, long range, high speed strategic reconnaissance (Photo: Center for Preventative Action)

Any new strategic reconnaissance and strike asset in development now could still be years from operational fielding, or it may already be in service. Recall that the F-117 Nighthawk was flying in 1981 but not officially revealed until 1988, a span of seven years during which the program remained hidden. While media has changed since the 1980s and it is more difficult to keep a program secret today, the possibility still exists that the program is much farther advanced than publicly revealed.

The F-117 sub-scale prototypes, some called “Have Blue”, were secretly flown from Palmdale without detection. (Photo: USAF)

As early as 1985 a line item appeared in the U.S. defense budget for $85 million USD attributed to a project called “Aurora”. By 1987 that allocation had bloated to over $2.3 billion for the same project. Some reports suggest the U.S. Air Force was working on an SR-71 replacement as early as 1988.

Subsequent reports in credible media like Jane’s Defense and Aviation Week & Space Technology have featured accounts of hearing and seeing unidentified aircraft in the region of the Nellis test ranges.

Another famous sighting happened over the North Sea in November 1991. Scottish petroleum engineer Chris Gibson, who was also serving in the British Royal Observer Corps according to reports, was working on the offshore oil rig Galveston Key. Gibson, an experienced and trained professional aircraft spotter, saw “The shape of a pure isosceles triangle” flying behind a KC-135 Stratotanker refueling aircraft in formation with two F-111s. The aircraft were sighted in the 6A air-to-air refueling zone according to reports. Gibson’s accounting was substantiated by another witness, lasted a significant amount of time, and has been repeatedly analyzed, but never explained.

The Chris Gibson/North Sea 1991 sighting suggested an early possible sighting of an SR-71 replacement. The sighting has never been explained. (Photo: Chris Gibson)

Trying to organize the sightings and information we have of any possible new hypersonic low-observable reconnaissance/strike aircraft with the mission requirements and global strategic need for aerial intelligence still leaves massive gaps between what we know and what is possible according to accounts, but within this massive gap of the unknown exists plenty of room for a real project that, when we eventually do hear about it, will undoubtedly be one of the most sensational defense and aviation stories of this century.

Top image: Distributed briefing slide showing conceptual image of SR-72 with SR-71. (Photo: USAF)

  • Steve Fortson

    Aurora wasn’t a program, it was the funding for the redesign of the B-2, to add the low level capability.

  • leroy

    Excellent report! The Prompt Global Strike (PGS) program is a U.S. effort to develop a system that can deliver a precision-guided conventional weapon airstrike anywhere in the world within one hour. So it would make sense that LM’s Skunk Works would receive funding to develop this type of a Mach 6 aircraft. An SR-72 would be able to hit any target on Earth within that 1 hr window.

    The radius of the Earth is approx. 4,000 miles. Speed of sound at 100,000 ft. is approx. 660 mph. So Mach 6 would put the SR-72 travelling at about 3,960 MPH. Round that to 4,000. So 4,000 miles to a target while you’re travelling at 4,000 MPH equals 1 hr. Bingo! You just met the requirements for the PGS program.

    Yeah, this is happening, the SR-72, and it will put any target anywhere on Earth at risk even when the plane is launched from inside the borders of CONUS (assume Whiteman AFB). And the plane will be undetectable and untouchable. Not even Russia’s useless S500 could catch/intercept it!

    Once again, the U.S. leads the way when it comes to cutting-edge aerospace technology. No nation on Earth even comes close to matching us. I fully approve, and enemies like Iran, Russia, North Korea (and others) had better watch out. Make the U.S. mad and we can come and get you like a boogieman quietly coming out your bedroom closet at night while you’re sleeping. If you’re a bad guy you had better be very, VERY frightened. Yes indeed – we are coming to get you! : )

    • Max Grishin

      Radius of the Earth? The SR-72 will fly to the target from the center of planet through layers of soil? :)

    • Ismeret Tenger

      4000 miles from Whiteman AFB not even reaching Europe. ;-)

  • BehindEL

    Great article. I guess we will just have to wait and see. It does make me wonder how many experimental aircraft have been developed, built and flown from these top secret bases over the past 20 years.

  • Ethan Mclean

    Reconnaissance these days is done via satellites, and for strikes a hypersonic low-observable missile would do just fine. Also, N.Korea, Iran ? Really ? Both could be handled with tech from a decade or two ago. As for point 4 – also non-issue as US has numerous bases all over the world and has no particular need to launch a recon platform from its soil. Same goes for Syria. All-in-all, looks like someone wants to get some of them sweet taxpayer bucks.

  • leroy

    Excellent report first of all. Yes it’s being built, and the plane will have a strike capability as part of the Prompt Global Strike Program. I wouldn’t be surprised to see it deploy hypersonic missiles too, which are under development (and may already be deployed, but that’s something no one can comment on due to national security reasons. Certainly my lips are sealed). Anyway, take a look at this recent report from AvWeek:

    Skunk Works Hints At SR-72 Demonstrator Progress

    “However, Weiss hints that work on a combined cycle propulsion system and other key advances needed for a viable hypersonic vehicle are reaching readiness levels sufficient for incorporation into some form of demonstrator. Following critical ground demonstrator tests from 2013 through 2017, Lockheed Martin is believed to be on track to begin development of an optionally piloted flight research vehicle (FRV) starting as early as next year. The FRV is expected to be around the same size as an F-22 and powered by a full-scale, combined cycle engine.”

    So yes an SR-72 test vehicle is flying (sub-scale with full-scale soon to come) and it will be unseeable and untouchable by any junk system the enemy might feebly try to deploy against it (think things like the junk S500 system which the U.S. and NATO will be able to defeat as they have S300/400 in Syria, or the too-slow, non-stealthy MiG-31, MiG-41). We will of course fly out of numerous NATO and Asia-ally airbases, and share it’s collected intel and of course have it fully participate in the defense of America’s NATO friends as well as Australia and Israel, Japan and South Korea, others.

    As an aside but still in the realm of aerospace advances, given many private ventures coming online (reusable rockets, space tourism, Moon and Mars near-future expeditions by private companies like Amazon and SpaceX, asteroid mining, etc.) this is an exciting time to be alive. Much like Apollo. We (the U.S. and West) are finally on the cusp of true space exploration and commercial space-resource exploitation (everything from asteroids to Helium-3 on the Moon). The U.S. will, as always, lead the way.

    America is gonna get rich beyond anyone’s wildest dreams (boy haven’t we seen a world economy driven by U.S. and Western innovation, know-how and entrepreneurial spirit since 1900) and more militarily and economically powerful than ever before. We are coming into a true Golden American Century – meaning lots of GOLD for the U.S. treasury and the American people. Allies will share in this abundance. Enemies (think Russia and rogue nations like North Korea, Iran, Cuba, Venezuela, others) will be denied any participation or benefit. SR-72 is just a hint of the fantastic technologies and vehicles soon to come!

  • su-34

    “The radius of the Earth is approx. 4,000 miles. Speed of sound at
    100,000 ft. is approx. 660 mph. So Mach 6 would put the SR-72 travelling
    at about 3,960 MPH. Round that to 4,000. So 4,000 miles to a target
    while you’re travelling at 4,000 MPH equals 1 hr. Bingo! You just met
    the requirements for the PGS program.”
    The earth is flat, so it’s a discus with a radius (Terry Pratchett proved it brilliantly), and the center of the earth is exceptionalistan…
    Flatheads also have a radius, so their reasoning falls flat…

    • Tomas Rodriguez

      Su34, your intentions are valid; but your “geo-mathematics” have a problem. This vehicle will not fly along the Earth’s radius. That would take it to the center of the planet. It will probably fly along a maximum circle circumference (the shortest distance on a sphere), which will be around 6.28 times that radius.

      Or maybe you were just being fascetious and making it funny. Then you have a point.

      BTW, yesterday (Oct. 13) Flight Global wrote an article titled:

      “USAF searching for hypersonic vehicle materials”

      Which begs a question. What material is the flying SR-72 using?* Go figure!

      *Somebody said: Unobtanium

      • su-34

        TR, sorry to disappoint you, but your math is also a bit lacking. To get from one point to anywhere on a sphere, you have to fly at most half of the circumference: Pi x (Hf + Re). That should be primary (commie) school knowledge, where I learned about the sphere.
        The first part is just a citation from the deep thoughts from the resident pindo genius’ deleted comment. (You’ll find him easily by looking at the number of comments).
        I just adapted the brilliant Terry creation to fit the world to our genius’ reasoning.

        • Tomas Rodriguez

          Su-34, I fail to get your point. Optimal long range navigation, in ideal conditions (friendly weather, borders, politics, etc.) is accomplishhed as close as possible along a segment of the maximum circle that passes through both points. For years, dispatchers planned flights for us that way. The length of a circumference in my neighborhood is 2 x 3.1416 x radius. Your formula looks impressive though. To be sincere, I got a Master degree in aeronautical engineering, which means that I don’t remember a damn thing about high school math (nor chemistry), and since that happened 59 years ago, I would not pretend to be right :-)

          BTW, the Su-34 is a beautiful airplane (except from the front, IMHO) and the only fighter-bomber ever with a toilet and a kitchenette! Probably a lesson learned from the 1986 USAF flight from U.K. To Libya and back that killed a Qaddafi’s baby girl. After the 11 hours mission, some crew were so exhausted they had to be extracted using maintenance cranes.

          • su-34

            You’re correct in two assumptions:
            – Shortest distance between two points on the surface of a sphere is along the circle that is created by the intersection of a plane determined by the two points of interest, and the center of the sphere, resulting in a circle with the same diameter as the sphere. Incidentally the intersection of any plane with a sphere, through the center of the sphere, is a “maximum circle”.
            – The circumference of that circle, and also of the sphere, is 2 x Pi x R

            Where you go wrong is that the maximum distance between two points on a sphere is not equal with it’s circumference but, at maximum, half of it.

            To be a little more precise, an airplane would fly at a certain altitude (Hf) above the surface that meaning the actual flight will be on a sphere with the radius equal with the sum of it, and the radius of the surface (Re) sphere, hence the (Re + Hf). Of course all this ignoring the speed of air, relative to the ground, on the various points of the flight path, and the fact that the earth is not actually a sphere, and other factors like those you reminded.

            To be sincere I’ve got no “master’s” degree – those are an invention imported from the limeys, and yanks, in the rest of Europe (the Bologna bullshit), thankfully (still) excluding Switzerland.

            • Tomas Rodriguez

              Now I see your point. You are adding the cruise altitude to the Earth’s radius, which is what you do for spacecraft, ballistic missiles and the like. For the aircraft in the article that may well be the case. For normal atmospheric vehicles, from airliners to steamships, that is ignored for understandable reasons.

              I only mentioned the Master degree to justify my forgotten Math (and Chemistry). Nothing to brag about. By the way, it was 49 years ago, not 59! They gave it to me in Europe and called it “Magister”, not Master. I never added it to any Resume nor signature. As a fresh graduate, I had not “mastered” a damn thing!

              It does not matter if you have a Master or not. I have met many Masters with no degree, and many, too many, Master degrees with no Master. You are very knowledgeable and that is what matters. Only the way you worded your original post made me think you meant to fly along the Earth’s radius. Obviously, I was wrong. And that is very good!


  • Tomas Rodriguez

    Obviously you are a naturalized “Americano” from Eastern Europe. Usually they tend to be exaggeratedly more U – S – A, U – S – A, U -S – A, RAH, RAH, RAH, than born Americans. Your comical gigapatriotism is insulting to the nice ordinary Americans that I befriend. With friends like you Americans do not need enemies!

    Did you ever hear of Nicolas Chauvin?

    What is clear is that it is absurd to take you seriously.

  • Uniform223

    That is probably just a tip of the proverbial ice berg…

  • Tomas Rodriguez

    Andrew, that was illuminating, at least for me. Thanks for your very useful effort.

    Same with your post about the “stealth” IL-76. You were spot on. I tracked the original Russian article. They never used the words stealth nor invisible; they wrote that it was equipped to fly at treetop heights in bad weather at night and be able to land undetected, behind enemy lines, using unprepared strips. For that they will land in complete darkness, without landing nor navigation lights. The electronics are meant to allow the operation and protection of those missions. So you were right. Again!

    The article David received was a version of a faulty translation that resorted to the fashionable words stealth and invisible. Nothing to do with him. Without David, who also questioned it, we would never have learnt about this project.

    Keep those soft landings!

    • Andrew Tubbiolo

      Thanks for tracking that down. The specifications you found in the original article are much easier to believe. And given the open nature of Western airspaces, I can see an initial raid of Il-76M-90s operating in just such a way. They may not make it back home, but they’d have a few hours to run amok. Fly in, land, dispense their cargo, then take off, and hope to make it home.

  • Pepe Le Cox

    I think you should read this article, to low down a bit your ego. My daughter is American and is far to think like you.

    • leroy

      I’m good with the U.S. military presiding over all others. I want us to be able to crush any opponent quickly and with a minimum loss of life on the American side. This for the sake of world peace. Brazil, China or Russia sure isn’t gonna guarantee that! The U.S. along with NATO will.

      We’ve kept nations free since WW-1. Or at least attempted to – with no gain whatsoever for ourselves. The world can’t live in peace and prosperity without us. No matter what continent you call home. Tell me where you live and I’ll tell you how the American people and military have kept your asses fed and free. I guarantee we’ve helped everywhere!

  • Or Russia buying American equipment for…everything! Ain’t that awesome?! :D

    • Pepe Le Cox

      I dont think Russia is buying american equipment a while ago, it’s banned all the tech transfer.

  • veej7485

    Stealthy at mach 6?

  • Wolfgang Hamburg

    Thesis 2: “ultra-high speed” is a solution.
    May be, but an integrated air defence systems can hand over possible targets from point to point. So advanced SAMs can reach such targets. May be not all of them, but one U-2++ disaster may be enough. Violation of enemy airspace is never a good idea in peace time. In war time is it even harder! You should be aware anytime you can be wiped out. This should be on your list with all consequences, military, politically and ethically.

  • Andrew Tubbiolo

    That’s not quite true. Satellites currently use 2.6 to 3 meter primary optics to image things from orbit, optics on aircraft have much smaller apertures. Aircraft do take higher resolution images, but the gap is not as large as you might think. The next generation of launch vehicles are going to have very high up-mass to low earth orbit, and sport 7 and 9m payload fairings. 8 meter primaries will go a long way toward closing the satellite to aircraft gap such as it is. It will probably put that relationship into reverse.

  • It is a colloquial term used to mean a lot of stuff without having to describe exactly what items, since that would be too numerous to count.

    From turbofan engine parts, to autopilot systems, to planes, to other items.

  • James Goodwin

    Or Kelly Johnson got bored with life in Heaven and came back to work in the Skunk Works.

  • Montezuma2011

    It was worth watching this video of a talk by the SR-71 pilot.

  • If this thing is designed to dart around the mesosphere don’t all the equations change?

    Range extension from some sort of hybrid space plane in NEO is what various agencies have been salivating over for decades. Lockheed is in a position to make at least some of their dreams come true, I picture a hybrid between an X-37 and NASP/X-30. The technological foundations, experience, and test platforms are there, Blackswift didn’t happen but some of the speed concerns become less relevant if you’re moving around in the mesosphere, less air to move out of the way less work to do as well as the substantial oblique recon bonus – I don’t buy the 185km/600k foot ceiling advertised by the S-400, maybe purely straight up on a static perfect target…but what about one 50-100km laterally separated at 100km altitude, the new Sr-72 with a whole slew of telescopes pointed out of the Q bay…there is more than likely a sweet spot close enough for surveillance whereby the S-400 is minimally threatening.

    Further we could cause some consternation among enemies, “Oh that? That’s a satellite, they have been overflying you for 50 years – are you going to start shooting down all satellites?” “Didn’t think so.” Additionally any worry of the thing skipping off the atmosphere and refusing to come down for a week is irrelevant due to the unmanned design, giving designers more flexibility than the past. Life support systems, oxygen, sandwiches, those are heavy :)

    Cue S-1000 ten years from now…