The US space shuttle program was a serious threat to the USSR
The US space shuttle program, stopped in 2011, has entered popular culture. Nowadays, the concept of space shuttle is partly taken over by space vehicles like the Boeing X-37B or the ESA Space Rider, but without crew. In the past, a space shuttle program in particular is astonishing in its scale and the progress of its development. This is the Soviet space shuttle program Buran.
In 1972, US President Richard Nixon launched the development of the Space Shuttle. The USSR immediately perceived the US space shuttle as a military weapon that would allow the United States to deploy prototypes of space weapons into orbit and then bring them back to Earth to continue their development. At the time, USSR thinks mostly of orbital lasers that would provide effective protection to the United States and its allies against Soviet intercontinental missiles. Deprived of its retaliatory capacity, the USSR would expose itself to a devastating strike. It was an unacceptable situation in the middle of the cold war.
Space shuttle Buran had to deploy lasers in space
As for so many other weapons programs, the only answer envisaged by the USSR is to equip itself with the same capabilities as its opponent. On 7 November 1976, Dmitry Ustinov, the Soviet defense minister, launched the space shuttle program Buran, a spacecraft with a clearly military purpose. Buran has to be able to deploy platforms equipped with missiles or laser weapons in orbit. This should allow the USSR to set up its own shield against Western missiles. These weapons are also designed to hit ground targets, and even other satellites.
In the early 1980s, the space laser race accelerated. Ronald Reagan launches the Star Wars program that concretizes the desire to have an orbital shield. The Soviet response leads to the development of two orbital modules. The Skif module has to ship a high-powered laser weapon, and Kaskad is a missile platform. To be completely effective, the Soviet shield must contain about twenty space stations capable of locating and destroying American missiles. Buran is in charge of putting them in orbit and refilling them with propellant and crew.
The ecosystem of the Buran program : a space shuttle, a rocket and a carrier aircraft
Because of its strategic importance, Buran mobilizes very quickly a large budget and many engineers. The KGB has to find the design and technologies developed by the Americans. The USSR relies heavily on this information. Thus, the first prototypes of Buran very closely resembles the US Space Shuttle. Buran is developed with other vehicles within an ecosystem. For example, the program gives birth to the Antonov An-225, which is still today the longest and heaviest aircraft in the world. This aircraft had to transport the space shuttle between its production and launch sites.
The Energia rocket is the main difference between the US Space Shuttle and the Soviet Space Shuttle. The Americans propel their spaceship thanks to engines integrated in the space shuttle and thanks to an external tank. Buran does not have high thrust engines. It is attached to a rocket, not to a an external tank. In the mid-1980s, when the American space shuttle had already been flying for four years, Buran began its atmospheric tests. A prototype is specifically designed for these tests. It made 25 flights between 1985 and 1988, charged with testing the behavior of the space shuttle in atmosphere. It has four jet engines. This allows the prototypes to take off and land without any help, such as an airplane.
The first flight of the space shuttle Buran impressed the world
Meanwhile, the first space shuttle to reach Earth’s orbit is built. At the end of the 1980s, the Soviet Union was finally ready for the first orbital flight of the Space Shuttle. The first launch took place in November 1988, and this remains the only space flight of the entire Buran program. Powered by the monstrous Energia rocket, Buran goes twice around the Earth before returning to land fully automatically. The flight did not embark crew, which shows a certain technical superiority over the US Space Shuttle, which can not function without a human presence. The program Buran does not stop officially after this flight, but the economic difficulties of the USSR and its burst slow down and stopped the program.
Despite its unique space flight, Buran is a fascinating program. Many engineers now believe that Soviet-style mission architecture using a traditional rocket was superior to US mission design. Soviet engineers have been very inspired by NASA’s work on the general shape of the space shuttle, but almost the rest of the system has a different philosophy.
The Energia rocket was very powerful
The Energia rocket had an operational career twice as big as the Buran space shuttle, since it flew twice. Its first mission in 1987 was to put into orbit the first component of a Skif military station. With a mass of 80 tons, this module was to test the ancillary systems necessary for the use of a high power laser from space, while pretending to be a scientific satellite. 37 meters long, it is the largest satellite in history to have been launched in a single launch. This module ended its life in the ocean but it remains the testimony of the progress of the Soviet military space program at the end of the cold war.
The Energia rocket is the second most powerful rocket in history, after the Saturn 5 of the Apollo program. Its role in putting the space shuttle Buran into orbit influenced its design. During takeoff, the four side boosters and the central stage are fired. As is often with the Soviets, powder propulsion is completely abandoned and everything works with liquid propellants. The four side boosters provide the majority of the thrust until they separate from the central stage, which has the role of the second stage of other launchers. It burns for a very long time and takes the space shuttle Buran to Earth’s orbit. Energia is a short but very thick rocket.
The Energia rocket was avant-garde
The central stage has a diameter of almost 8 meters. The space shuttle or the payload is placed on the side of the central stage. As a result, all boosters and engines are a bit off-center. This unusual configuration allows Energia to place 105 tons in low orbit. In addition, the rocket was planned to be flexible. The central stage could have worked with only two boosters. And the boosters were thought to be used as independent launchers. By the early 1980s, the Soviets had even begun a series of studies for a monstrous version of Energia with 8 boosters, which would have been able to place 172 tons in low orbit. This is a higher capacity than the SpaceX Super Heavy.
The boosters had been designed to contain parachutes, retrofuses and feet allowing them to return to land horizontally. Although we never had the demonstration, they were planned to be reused 10 to 12 times. This would have amortized the cost of losing the main engines at each launch. While the US Space Shuttle could reuse its very expensive RS-25 on every flight, Buran consumed a central stage of energy at each launch, including engines.
Automation, safety and motorization strongly distinguish Buran from the US space shuttle
The Space Shuttle Buran draws heavily on American design, such as dimensions, shapes, distribution of thermal tiles, etc. Soviet engineers quickly realized in the wind tunnel that American design was optimal. But there are still many differences between the two space vehicles, starting with the cockpit. While the US Space Shuttle was a flying grave for its passengers, Buran would probably have been a safer vehicle. The crew had indeed two ejection seats capable of operating up to a speed of Mach 3. But we do not know if that would have been enough to save the passengers of an accident like the Space Shuttle Challenger. In any case, Buran was much less exposed to this type of accident thanks to the use of liquid propellant boosters.
Buran was much more automated than the US Space Shuttle. It was able to take off, put itself in orbit and come back to land alone. Inside the cockpit, the consequence is a simpler and more rudimentary dashboard, with needle dials. Automation was also present in the cargo hold. Buran should have had one or two robotic arms, like the Canadarm of the US Space Shuttle. These robotic arms could have been programmed in advance to perform precise manipulations.
What differentiates most the two space shuttles is their engine. As Buran did not need to put itself into orbit thanks to the Energia rocket. It was equipped with orbital maneuvering engines and many micro-propellers. Soviet engineers had planned the addition of a small turbo-reactor to give some power to the Space Shuttle after its atmospheric re-entry. But it never flighted. Like the US space shuttle, Buran had to be powered by a fuel cell. But for its first flight, simple batteries have been used. Buran had many security systems based on its advanced automation. Program engineers thought that a computer could react faster than a human if something went wrong. Nearly 500 scenarios were recorded in the on-board computer to respond to all eventualities.
We can never compare the actual performances of Buran with those of the US Space Shuttle. It’s impossible to draw conclusions on the basis of a single flight.
Pictures credits : pictures.4ever.eu (computer generated image), NASA, Buran.ru, Roscosmos