In the meantime:
(Historical background for the events described in this section)
1951: Soviet government forms OKB-23 design bureau led by Vladimir Myasishev and specialized in the development of long-range strategic bombers.
1953 Jan. 20: Myasishev M-4 strategic bomber conducts its first test flight.
1955: Myasishev 3M bomber enters production.
1958 June 30: First Nike Hercules anti-aircraft missiles declared operational around New York, Philadelphia and Chicago.
1959 October: Myasishev M-50 supersonic strategic bomber conducts its first test flight.
1960 Oct. 3: Soviet government orders Plant 23 in Fili to switch from aircraft to rocket production.
During 1957, the USSR tested the intercontinental ballistic missile and launched the world's first artificial satellite. These achievements paved the way for the development of the spacecraft, which would be capable of carrying humans into space.
However a formidable challenge still remained - the safe return of the manned spacecraft to Earth. The ship's ability to dissipate its enormous speed on the way home and protect the crew during fiery plunge into the atmosphere would be determined by the aerodynamic shape of the vehicle.
Capsules or planes
In their very early effort to tackle the problem of returning to Earth, engineers at Sergei Korolev's OKB-1 envisioned a space plane, a reminiscent of rocket-powered gliders of the 1930s. Around 1957, such concept was studied by engineer Konstantin Shustin, the member of Gleb Maksimov's group within Department 9 of OKB-1. (At the time, Maksimov and his team was responsible for studies of manned vehicles and lunar probes at OKB-1) This work revealed that development of the system protecting the vehicle during fiery reentry faced serious challenges, which could take years to overcome. (196)
Since September 1957, OKB-1 in cooperation with NII-1 research institute conducted theoretical studies and calculations aimed to assess reentry temperatures and required thermal protection for return vehicles of various shapes. By January 1958, engineers favored a stubby conical capsule over the winged glider. (52)
Yet, for at least another two years, OKB-1 continued evaluating "pros and cons" of winged reentry vehicles. On September 9, 1959, Korolev approved a technical assignment for the TsAGI aviation research institute, which amounted to a detailed comparative study of gliding and ballistic reentry systems. Among other things, the document requested an analysis of aerodynamic shapes of hypersonic gliding vehicles; the evaluation of possibilities for development of aerodynamic control surfaces, which could help minimize heating problems; and the determination of various trajectories of gliding vehicles. At the time, the work was expected to be completed by the end of 1959. (84)
On the backstage
Although in the race to develop a manned spacecraft, Korolev's OKB-1 ultimately chose capsule-like vehicle, the idea of constructing a true spaceplane was not abandoned in the Soviet Union at the time. Decades after Yuri Gagarin's pioneering flight, post-Soviet publications revealed several secret projects of winged orbiters, which were under development concurrently with the famous Vostok spacecraft.
Korolev's allies in development of space planes came from aviation industry as well as its main client -- the Air Force. Both institutions could not ignore similar American projects, while, and at the same time, they faced uphill competition with rocketry at home.
As early as December 1957, the Soviet Air Force publicly displayed an ambition to extend its wings into space. On december 21, 1957, Sovetskaya Aviatsiya, an official Air Force newspaper, published a special issue on space technology, including an article entitled "Rocket-plane, the Aircraft of the Future" and signed by Candidate of Technical Sciences V. Aleksandrov.
Typically for a Soviet publication of this era, it provided no specifics on any current program, however the article did outline the "direction of thinking" within the Soviet Air Force. The article stated that advances in rocket technology paved the way to the creation of the suborbital supersonic aircraft. The author hypothesized a vertically launched rocket-powered vehicle, that would be capable of accelerating to 12,000 - 15,000 kilometers per hour in the upper reaches of the Earth atmosphere. During the following descent, the rocket plane would conduct multiple "skips," using the lifting force of the atmosphere until its kinetic energy is exhausted thousands miles later.
The article predicted that the nation possessing most powerful ballistic missiles would have the lead in development of rocket planes. (199)
As transpired decades later, soon after the R-7 ICBM got off the ground, OKB-1 provided specifications for the new rocket to OKB-23 in Fili near Moscow, led by Korolev's old friend and associate Vladimir Myasishev. (During Stalin's terror, both men ended up behind bars in one of infamous "sharashkas" -- a design bureau in prison.)
Myasishev had good reasons to experiment with such exotic technology as space gliders. An innovative designer far ahead of his time, Myasishev could not fail to see that rocketry was quickly making strategic aviation -- his main specialization -- obsolete.
Shortly after taking power in the Kremlin, Soviet leader Nikita Khrushchev, shifted focus of the Soviet defense strategy from aviation to missiles.
In his memoirs, Khrushchev's son Sergei recalled his father's visit to Myasishev's factory in Fili in 1954. Despite an impressive display of hardware presented by Myasishev, Khrushchev posed tough questions before designers about the ability of strategic aircraft to penetrate modern antiaircraft defenses. (87)
In the meantime, the US aerospace companies, including Bell, Convair and Boeing studied various configurations of rocket-powered suborbital and orbital planes during 1950s. (193) Although high level of secrecy surrounded such projects in the US, it is entirely possible that intelligence sources and publications in open press did provide the Soviet Air Force and the industry with the clues about the emerging technology.
Myasishev Project 48
In response to developments at home and abroad, Myasishev's team conceptualized four possible configurations of manned orbiters that could use aerodynamic forces to steer themselves during the reentry into the Earth atmosphere. After some additional research, original four concepts were narrowed down to the proposal of "Article 48," a winged vehicle launched by the R-7-derived booster. At OKB-23, Gennady Dermichev, a 1951 graduate of Moscow Aviation Institute, MAI, and the veteran of the M4 bomber development, was appointed a head of Project 48. Evgeny Kulaga was in charge of the airframe development. Institute of Aviation Materials, VIAM, led the development of the thermal protection system.
According to post-Soviet sources, a large group of scientists, including leading Soviet theoretician Mastislav Keldush, worked on determining basic design of Article 48. A crucial meeting on the subject took place in April 1960, with the leading specialists of aviation industry and OKB-23 in attendance.
Again, various shapes of the vehicles had been evaluated, including a helicopter-like landing, so favored by Korolev.
Between March and September 1960, two versions of the vehicle evolved with the mass of avionics totaling 600 kilograms. The vehicle could carry 700 kilograms of payload, including a fully suited pilot and a 160-kilogram ejection seat.
A number of systems for Project 48 was borrowed from the Vostok spacecraft, including the "Zarya" communication gear.
The Vehicle 48 would blast off vertically on top of the Vostok booster. The spacecraft would have an estimated mass of 3.5 or 4.5 tons and it would be capable of reaching a 400-kilometer orbit.
Upon completing the orbital part of the mission, the vehicle would reenter the atmosphere and conduct a controlled gliding descent from the altitude of around 40 kilometers. It had capabilities for side maneuvers up to 100 kilometers and up to 200 kilometers along its trajectory. An air-breathing jet engine could provide additional 100 kilometers of maneuverability.
At the altitude of around eight kilometers, the pilot would eject and release a parachute at the altitude of 8 - 3 kilometers. A backup parachute could be used from the altitude of 2 kilometers.
The spacecraft would land independently (with its own parachute system?) using special ski-like amortization gear. The vehicle could be then refurbished and reused.
Thermal protection challenges
Despite extensive experience in design of jet bombers and recent work on the intercontinental cruise missile, engineers of OKB-23 faced serious difficulties in solving technical problems presented by Project 48, first of all in the field of thermal protection.
The bottom side -- or around 40 percent of the external surface of the vehicle -- would heat up to 1,500C degrees during the reentry, while the nose section would experience even higher temperatures. Surfaces on the top portion of the vehicle would experience temperatures up to 1,100C degrees.
For comparison, the Buran cruise missile, previously developed at OKB-23, would not experience temperatures above 280 C degrees in the most critical areas of the wing's leading edge.
The ablative protection system adopted for capsule-like spacecraft -- which melts away in layers -- was not acceptable for a glider, as it needed perfectly shaped and constant aerodynamic surfaces for a stable flight.
Designers at OKB-23 evaluated surfaces made from niobium which could withstand very high temperatures without external thermal covering as well as regular aluminum airframe protected with a foam-like ceramic material. They soon found out that niobium would not withstand the heat of reentry and would require external protection, in which case it would be less weight-effecient than protected aluminum structure.
Resorting to a ceramic foam as thermal protection brought its own problems. Such materials were extremely fragile and would tolerate very little stress deformation in the underlining wing structure before developing cracks and failing. To get around the problem, engineers apparently proposed to apply the protective material to the body of the spacecraft in the form of square panels -- precursors of thermal protection tiles on the Shuttle and Buran orbiters. Interfaces between tiles had angled edges to absorb flexing of the system under stresses of flight. Existing crevices between tiles would be filled with quartz wadding soaked in organic silica.
Prototypes of such thermal protection system were tested in the exhaust stream of the jet engine and proved reliable as long as the tiles had equal thickness.
Precursor to Stealth?
In his memoirs, Evgeny Kulaga, who worked on thermal-protection materials at OKB-23, claimed that work on the Buran cruise missile and later on Project 48 led to the development of composites "transparent" to radar radiation. Coincidentally, published designs of the early version of the orbiter from Project 48 showed superficial resemblance to the US F-117 Stealth aircraft. It should be noted, however, that original drawings of Vehicle 48 were destroyed and published designs were post-Soviet reconstruction. (198)
In the post-Soviet period, Kulaga became a source for a number of articles in the Russian press, documenting his claimed attempts to promote the "Stealth" technology. According to one publication, Kulaga proposed his boos at OKB-23 to develop an "invisible" aircraft at the end of 1959. Myasishev apparently took the idea seriously and considered the application of such technology for a high-altitude reconnaissance plane, whose development he inherited from OKB-256, formerly led by Pavel Tsybin.
End of Project 48
Project 48 never left the early development stage. In 1960, Khrushchev ordered the transfer of Plant 23 in Fili under control of Vladimir Chelomei, who inherited blueprints of Vehicle 48, as well as other space-related projects conceived by Myasishev team, along with enormous development and production potential of OKB-23 in Fili.
Myasishev was not the only Soviet aviation designer who studied wigned spacecraft at the end of the 1950s. In 1958, Korolev requested his old associate Pavel Tsybin, then a head of OKB-256 design bureau specialized in high-altitude supersonic aircraft, to develop a manned winged space vehicle. (197) By May 1959, Tsybin returned with the proposal of a spacecraft which could be launched by the R-7-derived launcher and equipped with its own liquid-propellant braking engine and folding wings, providing landing on the runway at the speed of 180 - 200 kilometers per hour. The vehicle could also carry its own attitude control system.
On May 18, 1959, Korolev sent a letter to the State Committee on Defense Technology, GKOT, asking to include the project into the general plan for space exploration.
"The development of the proposed winged vehicle is one of realistic and promising ways of descent from orbit and landing on Earth. It is clear from the proposal that its implementation presents a practical engineering task, which under right conditions can be achieved in a very short time," Korolev wrote. (84)
Despite this optimistic forecast, technical challenges of thermal protection coupled with a major reorganization within the Soviet aviation industry at the time left the project on paper.
Vladimir Myasishev. Credit: Khrunichev
Artist renderings of a winged space glider studied at Myasishev design bureau at the end of the 1950s. Click to enlarge: 500 x 375 pixels / 28K Copyright © 2005 by Anatoly Zak
Artist reconstruction of the early concept of Myasishev 48. Click to enlarge: 400 x 299 pixels / 40K Copyright © 2004 by Anatoly Zak
Artist reconstruction of Myasishev 48 vehicle in orbit. Click to enlarge: 400 x 320 pixels / 136K Copyright © 2004 by Anatoly Zak
An artist reconstruction of Myasishev 48 vehicle during landing. Click to enlarge: 400 x 321 pixels / 80K Copyright © 2004 by Anatoly Zak
...Almost a rocketplane. Myasishev M-50 supersonic strategic bomber. Credit: Khrunichev
...A decade after the end of the Cold War an abandoned radar and launch control site for the Nike anti-aircraft missile was rusting away on a hill overlooking New York City. Back in the 1950s, it was a part of the defense ring circling major US cities to form a formidable obstacle to the Soviet long-range bombers and, as a result, prompting Russian designers and the Air Force to consider more advanced aerospace systems. Click to enlarge: 308 by 400 pixels / 80K Copyright © 2003 by Anatoly Zak