Sidebar: The Tupolev OOS

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A model of the OOS shuttle, believed to be from a Russian magazine in the 1990s. If you have more information about this picture, please contact the author.

During the 80s the USSR’s space program stayed remarkably focused on Energia/Buran and the Mir space station, especially when compared to the infighting that marred the years 1966-1975. It fended off or adapted to a number of distractions, whether it was Vladimir Chelomei‘s repeated attempts to regain his previous, short-lived position on top of it, or airplane design bureaus suggesting anything from conservative alternatives to the recently discussed Myasishchev M-19 nuclear scram/ramjet.

The OOS was a late Soviet-era shuttle proposal from the Tupolev bureau, an also-ran in that country’s space business despite a strong position in civil aviation and strategic bomber development. Proposed as a fully reusable replacement for Buran sometime around the year 2000, it was about the same size as that craft or the American Space Shuttle, though somewhat heavier at 100 tonnes when fuelled. With a crew of two cosmonauts. it had a payload of 10 tonnes to and from low-Earth orbit.

If you’re a long-time reader of this blog, or just sufficiently into spacecraft, you probably slotted the shuttle pictured above toward the conservative end of that spectrum. Apart from the more-rounded contours, it looks to be much like the Shuttle, particularly in the shape of the underside. There, too, we have the usual ceramic tiles for dissipating the heat of re-entry. The engines are not visible, but I can tell you that there were three, burning LH2 and LOX during the ascent to orbit (though, curiously, switching out the hydrogen with kerosene for orbital maneuvers). Knowing that would likely not change your opinion at all.

Given that it’s was to be fully reusable, the ten-tonne payload mentioned earlier may have got you wondering, though. The actual American and Soviet shuttles had payloads in the 25-30 tonne range, so alright—there’s clearly some sort of tradeoff there. You’d be well-advised to wonder about the rest of the OOS’s configuration. Side boosters but no external tank? Perched on a reusable rocket in some manner, maybe?

Well, no. “OOS” stood for Odnostupenchati Orbitalni Samolyot, ‘one-stage orbital plane’, But a single-stage-to-orbit craft the size of the Orbiter? Surely that’s not possible.

This goes to show that you don’t think like a Soviet aircraft designer circa 1989. The OOS was to have been air-launched, and the other half of the system was the Antonov AKS:

AKS

Aerospace aficionados will remember that the An-225, which was used to piggy-back the Buran shuttle around the Soviet Union, was by most measures the largest aircraft ever built. This is two of them, one wing apiece removed and replaced with a sort of aerodynamic bridge, and then 675 tonnes of spacecraft and rocket propellants attached to its underside. It had twelve turbojet engines for when it flew without the orbiter attached (the dark circles in the diagram above, at lower right), with a supplementary ten more being added during launch operations (the white circles). The Aristocrats! With a length of 83 meters (272 feet), a wheelbase of 40m (131 feet) and a wingspan of 153m (502 feet), the combination came in at a whopping 1650 tonnes. By contrast, a fully fueled late-model 747 has a maximum takeoff weight of just under 440 tonnes.

There has been only one successful air-launching system in the world to date, Orbital ATK’s Pegasus. It weighs 23.1 tonnes and can put 0.44 tonnes in orbit; it’s launched from a Lockheed L-1011, already getting into the neighborhood of large airplanes. So start with some skepticism that 20 times this in launch mass and payload are a possibility for the late-era USSR.

Further, I haven’t (unfortunately) been able to find a detailed description of the AKS/OOS’s mission profile. I’d like to see it because I’m having a hard time picturing what the moment of separation would look like. Or rather, I have an image of the support crew aboard the AKS bouncing around like ping-pong balls in a boxcar once the plane, straining to get the orbiter to altitude, suddenly cuts loose 675 tonnes. For that matter, the OOS would have to light its engines pretty quickly thereafter or defeat the purpose of an air launch. As these were in the same class as the RS-25’s on the American Shuttle—the noise aboard the AKS, now presumably not all that far above and behind it, would have been intense.

I’m on record for my begrudging appreciation of the come-what-may technological megalomania that gripped the superpowers post-WWII. The US grew out that uncritical mindset after Love Canal and Three Mile Island, while the Soviets carried on until 1989. That extra time coupled with fossilized technocrats in charge allowed awe-inspiring audacity in technology of it to grow even greater than it did in the West.

Even so, I can’t imagine anyone with the power to make the Tu-OOS happen actually doing so. It would have been an immensely expensive and difficult project right at a time when the Soviet Union was in no position to take one up, and technological limitations would have prevented anything like it at an earlier point in that country’s history. The OOS/AKS was a paper project, and would have remained so.

Sources:

OOS, la bestia de Tupolev y Antonov

OOS, el sistema espacial de lanzamiento aéreo definitivo

Artist Vadim Lukashevich has numerous renders of the AKS/OOS combination on Buran.ru (screll down to the second half of the page).

Readers will note a lack of primary sources here. I’m convinced of this project’s existence, but any pointers to a source that’s a little more direct than what I’ve relied upon here would be most welcome.

 

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M-46/M-48 (VKA-23): The First Soviet Spaceplane

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The VKA-23’s two designs, Vladimir Myasishchev third attempt in the 1956-60 period to propose a small spaceplane to Soviet leadership. The one on the left was based on his second try, the M-48, while the second design, on the right, was the ancestor of several other Soviet attempts at a lifting body re-entry vehicle in future years. Based on two images of unknown source, believed to be from the USSR–if you know of their source, please contact the author. Click for a larger view.

What it was: Four interrelated, but different, designs for a small Soviet spaceplane. While almost all Russian spacecraft descend from Sergei Korolev’s R-7 and Vostok, they began as an independent line of approach pre-dating 1957, building up to orbital operations by creating ever more extreme airplanes. Only after Korolev’s crowning achievement of orbiting Yuri Gagarin in a ballistic capsule was it definitively folded into the main line of Soviet space exploration. Even after that its descendants repeatedly threatened to split back off again right up until the collapse of the Soviet Union.

Details: We’ve previously discussed Eugen Sänger’s Silbervogel and how it was the first serious attempt to build a spacecraft by an alternative means to ballistic rocketry—building a plane so extreme that its speed and height qualified it for orbit. After WWII ended there was some interest in his work in the United States, but as designing a spaceplane is relatively difficult as compared to a ballistic capsule, it never went anywhere interesting until the development of the X-15.

In the Soviet Union, however, airplane designers kept their eye on the possibility starting as soon as they discovered Sänger and Bredt’s work. Stalin is reported to have been very interested in the possibility of an orbital bomber, and in 1947 tried to have a Soviet rocket engineer, Grigoriy Tokayev, convince Sänger to come to the Soviet Union or, failing that, have the NKVD kinap him (Tokayev chose to defect to the UK instead). Before this, though, in November 1946 Stalin directed Mstislav Keldysh—arguably his most talented plane designer and one of the three men (along with Sergei Korolev and Mikhail Tikhonravov) who suggested in 1954 that the Soviet Union launch an artificial satellite—to build something like the Silbervogel.

Keldysh concluded that the Silbervogel was entirely too advanced for Russian industry to build any time soon. Nevertheless he went for a somewhat less-extreme ramjet-and-rocket-powered craft that kept the same basic suborbital boost-glide approach suggested by Sänger. What he comes up with is still too sophisticated for Russia to make, so it’s not hard to conclude that it wasn’t a serious proposal and more just a way of getting Stalin off his back.

In the years immediately following this, Vladimir Myasishchev was the most serious of early Russian spaceplane designers. Well before Sputnik I his design bureau, OKB-23, was working on radical weapons like supersonic bombers and the Buran cruise missile. When Korolev demonstrated to the Soviet leadership’s satisfaction that ballistic missiles were the best delivery system for nuclear weapons, Buran was cancelled in November 1957, but Myasishchev was still interested in going faster and higher with his planes. So he continued working on an idea he’d had while working on his missile for a suborbital reconnaissance spaceplane called the M-46. Note the date: he was already working on it prior to the launch of Sputnik I, which makes it one of the select few spacecraft seriously considered before the dawn of the Space Age.

Not a lot is known about the M-46 other than its existence, as the work was done entirely on Myasishchev’s own accord; when he was found out he was sanctioned and told to pay back the funds he had spent. Archive materials on it were apparently destroyed some time thereafter. Nevertheless, there’s reason to believe that it would have been a manned version of the Buran missile, which is to say a ramjet-driven, delta-winged craft some 23 meters long, boosted up to speed by four nitric acid/kerosene rockets. The ramjets would have gone out for lack of oxygen long before it reached space, but it would have had enough speed for a suborbital hop above 100 kilometers with an intercontinental range.

Two years after being slapped down for his initiative, Myasishchev’s situation changed. Early reports of the US Air Force’s Dyna-Soar inspired the Russian military to counter with a spaceplane of their own. Korolev’s OKB-1 worked with Pavel Tsybin to develop one possibility, the PKA, while Myasishchev’s OKB-23 was given the go-ahead to develop a new one of his own, which he called the M-48. Both were designed to be boosted by Korolev’s R-7, just like the Vostok spacecraft for which they were considered an alternative. As it’s much easier to build a ballistic re-entry capsule, Yuri Gagarin made his historic flight in the relatively unsophisticated Vostok 1, but work continued on both the PKA and the M-48 until October 1959 and October 1960 respectively.

Myasishchev’s first attempt at this commission produced the M-48 proper, about which again not very much is known. One day the Soviet archives may open enough to give us more details, but for now our best idea is that it was long, flat-bottomed, triangular craft (with the two forward sides of the triangle much longer than the other one,) with a relatively simple faceted crew cabin for one attached to its upper surface. Its flat underside is particularly interesting, as it makes the M-48 one of the first waveriders, which is to say it took advantage of the shockwave on the belly of the craft to provide lift. The whole concept of doing this had only been discovered in 1951, and its discoverer (Terence Nonweiler) was only just developing a plan to use it (in the never-built British Nonweiler Waverider re-entry vehicle) as OKB-23 was doing the same. Waveriding is a difficult and sophisticated technique, and even in the 21st century only one aircraft has ever been built that used it, the 60s-era XB-70.

Perhaps it was that sophistication, as well as the general audacity of designing a spaceplane, that got the M-48 into trouble. When Myasishchev submitted his design for approval, it was savaged by governmental engineer/bureaucrats, and he had to head back to the drawing board. This time he came up with two designs. Though technically still the M-48, they’re sufficiently different from the original (and from each other) that they’re usually referred to by their alternate designations: VKA-23 design 1 and VKA-23 design 2.

The first of the two designs was similar to what he had done with the M-48, but with changes intended to address the objections to the previous design. It would have been 9.4 meters long and built of steel and titanium, which would then be covered with ceramic foam tiles embedded in a frame made of silicon and graphite. It would have been able to carry one pilot and 700 kilograms to orbit, with the entire loaded and fuelled craft weighing an additional 3500 to 4100 kilograms. This is very small, smaller than even SpaceShip One and only a few hundred kilograms heavier than the unmanned X-37 spaceplane. This size was dictated by the fact that it was to be lifted by one of Korolev’s R-7 boosters, which would do most of the work of getting it into orbit.

The second design is the particularly interesting one, though. In contrast with the first design’s faceted appearance, this one was a rounded lifting body, recognizably like almost every small winged re-entry vehicle developed since then. On the Russian side this is not coincidental. The chain of proposed Soviet mini-spaceplanes running from Raketoplan to Spiral to LKS to MAKS are all dependent in one way or another on the work done on it, or the engineers who developed it. Like design 1, it had to be light to go up on an R-7, and so it rang in at 3600 to 4500 kilograms, and its payload was the same—700 kilograms. It likewise used the same ceramic tiles and silicon/graphite frame as a heat shield. It was slightly shorter than its brother, at 9.0 meters.

Both would have been fitted with a small turbojet engine for maneuverability once they had reached the lower atmosphere during re-entry.

Despite its numerous descendants, the VKA-23 was still quite primitive. In both designs its one astronaut actually had to take a trick from the similarly basic Vostok and parachute out from it to safety once he dropped below 8 kilometers (but before getting to 3 kilometers); the plane itself would have had landing skids (design 1) or had a parachute to bring it safely to ground (design 2).

What happened to make it fail: In 1959-60 Khrushchev starting reducing the size and complexity of the Soviet military establishment. OKB-23 was dissolved in October 1960, and many of the VKA-23 engineers were re-assigned to Vladimir Chelomei’s OKB-52, where they became an important part of his Raketoplan spaceplane design team. When that too was cancelled, they were moved to Mikoyan, where they worked on Spiral.

What was necessary for it to succeed: None of the original four designs was ever going to fly. Spaceplanes have turned out to be considerably harder than anyone ever suspected, and even the United States was far away from building one in the late 1950s and early 1960s. The Soviet Union was even less able to do so.

But In a sense, Myasishchev’s little plane came very close to succeeding in the long run. During all their travels through various Soviet design bureaus, a variable group of Myasishchev engineers kept a recognizable core of VKA-23 design 2 knowledge moving forward. A scale testing model of Raketoplan was launched on a suborbital re-entry experiment in 1961, and another model tested the design’s hypersonic maneuverability in 1963. The Spiral spaceplane got to the point of a full-scale subsonic version, the MiG-105, which was used to study its low-speed handling. Two sub-scale versions of Spiral, BOR-2 and BOR-4, were launched into orbit. Even the larger-scale Soviet shuttle that did finally fly in 1988 had its cockpit designed by the Myasishchev bureau, which was reconstituted in 1967. It had the name Buran, which was a nice callback to the manned Buran cruise missile plans that started it all in 1956-7.

Incredibly, the Myasishchev design bureau was still chugging along on their own distant descendant of the VKA-23 (after a long fallow period) as late as 2009—this time with the aim of using the result for space tourism. That dream finally died when they were acquired by the Russian government’s United Aircraft Corporation in that year.