MASS: The Manned Anti-Satellite System


MASS schematic as shown in Transactions of the Eighth Symposium on Ballistic Missile and Space Technology (Vol. II). The launch vehicle was to be a Titan III, while the command module was based on research into lenticular missiles for the B-70 bomber. Public domain image via the USAF.

What it was: A conceptual design for a manned satellite interceptor/killer, floated by General Dynamics in 1963.

Details: The B-70 bomber was conceived to fly high enough and fast enough that it could out-run any possible intercepting aircraft, but before the program was well underway it became clear that surface-to-air missiles posed a problem, and that the USSR was good at building them. In December 1959 the USAF decided to build only one prototype (two were eventually built) for experimental purposes and that was that for the B-70.

There was a short interval before cancellation where the USAF explored putting anti-missile missiles on board the B-70, under the unusual code name of Pye Wacket (probably taken from Kim Novak’s feline familiar in the 1958 supernatural comedy Bell, Book, and Candle). The B-70 flew at such great heights and speeds that making a conventionally shaped missile that could attack on any vector away from the craft proved to be problematic. The Pomona Division of General Dynamics assigned to the project instead settled on a lens shape for the body of the missile, which would make it more maneuverable than the conventional “long-and-thin” approach.

When the B-70 was cancelled so was the missile project, but here the story of the MASS begins. Lenticular shapes were one of the three early contenders for manned spacecraft in the early American space program (along with ballistic capsules and winged re-entry vehicles) and Pomona Division got the idea to scale up the Pye Wacket body into something an astronaut could ride. This was written up and proposed to the USAF in March of 1961.

There’s not a lot of public information about Pye Wacket, given that it was developed as a defense for a cutting edge nuclear bomber, and the larger manned, version was classified too: it seems to have been a dark horse running for the role proposed for the X-20. Much of what we know about the craft comes from a single unclassified paper called “Manned Anti-Satellite System” (MASS), published in October 1963, presumably because it had been definitively ruled out by then. The X-20 itself was cancelled outright in December of the same year.

What General Dynamics proposed was a boost-glide craft, perched atop a Titan IIIC for the climb to orbit. It consisted of a 16-foot in diameter (4.9 metres), 8500-pound (3855 kilograms) lens-shaped command module, which seated three, and a 6200-pound (2812 kilograms) mission module, the latter of which would store a little over 7 US tons (6500 kilograms) of propellant—N2O4 paired with 50/50 hydrazine and UDMH.

The most interesting part of the mission module was its “inspector/killer” modules, four of which studded the sides of the orbiting vehicle. These were protected during launch by “wind shields” or, in modern parlance, payload fairings. Once in orbit the fairings would be dropped and the craft as a whole maneuvered into proximity of a target Soviet satellite. At a standoff distance of 50 miles (80 kilometers), the crew would order one of the inspector/killers to detach and then it would close with the target using its two restartable engines.

Each inspector/killer would be 47″ x 38″ x 38″ (about 1.1 cubic meters) when folded up, but once detached it would unfold a two-foot antenna so that it could send a video signal back to the command module, as well powering up a tracking radar with two antennas (one to lock on the target and one to lock on the command module), a TV camera, a flood lamp (in case the target was in the Earth’s shadow) and an IR detector.


An I/K closes in for a an attack on its target, while the manned section of the MASS lurks at a safe distance. Public domain image from Transactions of the Eighth Symposium on Ballistic Missile and Space Technology (Vol. II).

After inspecting the target, the crew of the MASS then had the option of detonating the shaped charge aboard the inspector/killer so as to destroy the target. As well as its two rocket engines, the I/K was outfitted with six attitude control motors, and using all of these it could even chase after a target that was designed to evade an attack; the I/K’s main motors could push it at 12g if needed.

With up to four satellites destroyed, and potentially more inspected depending on how the targets’ orbits were arrayed, the command module would disengage from the mission module and return to Earth. Its lenticular shape allowed for a very high angle of attack (60 to 75º) to bring its ablative heat shield into play while still giving it a good lift-to-drag ration (∼2 as compared to the 1.0 of the Shuttle Orbiter). Once it was down to transonic velocity it would deploy two horizontal stabilizers/small wings, which were necessary due to the craft’s instability at these speeds as well; they also improved the command module’s L/D ratio considerably.

What happened to make it fail: The MASS is a perfect storm of ideas that seemed promising in 1960 but that turned out to be dead-ends. Lenticular craft have never promised enough advantages to be built, the proposed customer—the USAF—never did get its own manned space program, and its proposed mission to intercept, inspect, and potentially destroy satellites has never been worthwhile in practice. In the X-20, it was also up against a strong competitor that had already got underway when MASS was proposed.

What was necessary for it to succeed: It’s awfully hard to get this one to fly. Perhaps if Eisenhower hadn’t been so insistent on giving space to a civilian agency, and if the USAF had been able to fend off the Army to gain it for themselves (far from a foregone conclusion even in the absence of NASA), MASS might have moved further. Even under those circumstances we would have been much likelier to see something like the X-20 or the Manned Orbiting Laboratory rather than the MASS.

When it comes down to it, this proposal placed bets on too many things that, in retrospect, never worked out. It’s interesting as a concrete example of how much we didn’t know in the early 1960s but, with the exception of the Project Horizon Lunar Base, it’s the least likely of all the post-Sputnik projects we’ve examined.

On the other hand…for those of you who (like the author) enjoy stories about conspiracy theories, black projects, UFOs, and the like without actually giving them any credence, I’ll direct you to a strange Pye Wacket-related article published in Popular Mechanics’ November 2000 issue. It makes the case that the MASS wasn’t cancelled but instead went black and turned into a vehicle called the LRV. Fair warning, though: the words “Roswell”, “Nazi”, and “flying saucer” are used in all seriousness.


“Manned Anti-Satelllite System”, E.E. Honeywell; Transactions of the Eighth Symposium on Ballistic Missile and Space Technology (Vol. II); Defense Documentation Center, Alexandria, Virginia; 1963.

“Pye Wacket”, Mark Wade,


8 thoughts on “MASS: The Manned Anti-Satellite System

  1. This actually reminds me of another dead end project of that period called “SAINT”(“Satellite Inspection Technique”) that was based on the Gemini capsule. It was to have been unmanned with small missiles of some sort in the nose cone in place of the recovery system. I recall that there was an actual photo of SAINT in an issue of Mechanix Illustrated and it was a little weird looking because it also lacked the two windows of the regular Gemini capsule. Have you ever come across any info re SAINT in your research?

    • You’re not the only one to make the connection. Mark Wade over at Encyclopedia Astronautica is of the opinion that the MASS was was NAR’s submission to the USAF for the SAINT-II lifting body (which was to follow SAINT, and eventually led to Martin’s submission turning into the Martin X-23). I’ve not seen any documentary evidence of that, but the circumstantial case is pretty good.

      • Really? What has he got on SAINT? I`ve been thinking about the damn thing for years since grade school and I`ve never been able to find ANY information on SAINT.
        As an aside though I`d like to say that I`ve been coming here for about three years now and I`ve enjoyed every word that you`ve written: it takes me back to the days when this stuff held me spell bound as a young child. If you`re ever up this way(Winnipeg, Manitoba, Canada) you`ve got an invitation to drop by and sample some of my best dark beer!
        Mike in Winnipeg

          • Wow, the information available there is incredible: I may spend part of my vacation this year just working my way through the alphabet! I was especially pleased to see all the info on the Nerva engine program, which is a little hard to come by(although I`ve had an even tougher time getting anything on a Los Almos design that was called “Dumbo”). Looking forward to your next article and remember, there`s always a few cold ones waiting for you if you ever find yourself in this neck of the woods.

  2. A note but the linked article is not Pye Wacket related. All “lenticular” vehicles are not the same, nor related 🙂 Specifically the “Lenticular Reentry Vehicle”(s) were significantly different from the Pye Wacket lenticular in mission, layout, and capabilities. The LRVs were a way to square the circle between a controllable (flying) landing vehicle and a blunt-ballistic entry shape, while Pye Wacket, (and MASS) arrived at the lenticular shape by way of finding a compact, high speed body which had sufficient space inside for use, (and not much of it in MASS) while being capable of handling significant off-axis aerodynamic pressure long enough to get stabilized.

    The LRV’s were actually pretty roomy compared to MASS, but unlike that body aerodynamically they were less capable of maneuver until they reached low-supersonic or sub-sonic speed. MASS would have been capable of significant maneuvering at hypersonic and high supersonic speeds even before it deployed it’s wings whereas the LRVs for the most part had to be sub-sonic to deploy the wings and fly. In the case of the larger LRVs, (the PM article is on one used as an orbital missile control, repair, and transport vehicle NOT an AS vehicle by the way) they didn’t even need wings as their shape allowed them to fly without additional lifting surfaces. (CONTROL surfaces were a must though, I’m not sure given everything published and available on disk aerodynamics how all the UFO and Nazi-flying-disk folks can think for a moment that it is a ‘superior’ aerodynamic shape)

    In the main the biggest reason that MASS would have been considered as a manned vehicle is the same reason why the military wouldn’t have been interested (for the most part) in using a standard LRV body for the mission: Aerodynamics.

    LRV bodies (the smaller MASS size ones at any rate) are/were normally considered for launch in a ‘flat’ position whereas the PW-based MASS would be aerodynamic enough to launch as shown. A key bonus why it might have beat out something like the X-20 in a general way was that it’s aerodynamic loading on the Titan LV would have been significantly less than the winged X-20 requiring fewer changes than to fly that vehicle on the same launcher. Of course Blue Gemini would require none at all aerodynamically so that would have been probably, the ‘best’ choice, but it all depends on the main criteria. The X-20 would have been capable of carrying more cargo or personnel inside than either BG or MASS but either of them would probably have been more efficient at the AS job than the X-20 so it’s relative.


    • Your article did point me in the direction of the paper (viz. and the post is based on that — not a recycle of yours. You make a good point that your post was the first I’d heard of it, though, so I’ve added a link to it in the sources, as well as one for the Sukhoi Albatros of the other week. Your work on that *was* the primary source for mine, and I apologize for not including it there when it was published.

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