Ask people about the space shuttle and they think of NASA, the American space program, the International Space Station, Challenger and Columbia and possibly an obscure Star Trek reference¹.

But they probably won't think of the Russian space shuttle, Buran. Its name means 'snow storm'.

Development

The Soviet government began designing Buran in 1976, as a response to NASA's shuttle program, and although NASA's goal was the further exploration of space, the cheaper launch of satellites ² and carry out space science, the Soviet's primary goal was to carry nuclear weapons to orbit, although some science was also planned. The development of Buran can also be seen as another branch of the space race between the USA and USSR.

Similar to the NASA approach, the Soviets first started with experimental aircraft, the MiG 105-11 'Spiral' experimental manned orbital aircraft (Experimental'nyj Pilotiruemyj Orbital'nyj Samolet - EPOS) which flew in 1977/78 and helped in the development of the Soviet Space Shuttle. Later they moved on to one-fifth scale models of Buran, then a full scale atmospheric model to test the glide and landing abilities. After only 24 flights, this vehicle was damaged and unable to fly again.

The atmospheric model was their equivalent of the Enterprise shuttle, which never flew in space but was built for atmosphere testing. Again, the Russians did things differently. The Enterprise was attached to the modified Boeing 747, flown to a specified height and released to glide back to earth. The Buran atmospheric test model had two jet engines bolted onto the side of it, at the rear.

Comparison Of Designs

To simplify this comparison, the NASA shuttle will be called by its official designation, STS, standing for Space Transit System. The Russian shuttle will be referred to as Buran.

The STS (or orbiter) is attached to the centre liquid fuel tank. Strapped to the sides of the tank are two solid-fuel rocket boosters. Two minutes after take off, the solid fuel boosters are depleted and jettisoned. Parachutes in their nose-cones allow them to splash down in the sea and be recovered. Seven minutes later, the centre fuel tank is jettisoned. It burns up in the atmosphere and is destroyed. NASA used to paint this tank white, to match the rest of the vehicle until someone pointed out that this paint weighed seven tonnes. It was more economical not to paint it, allowing more payload instead.

In overall design, Buran is nearly identical to the STS. Immediately noticeable is a sharper edged wing design, squarer, which reduced drag on take-off and re-entry. The Soviets did think about copying the American design exactly, but were worried about heat build up on the wing surface and drag during lift off.

Buran is 4600kg lighter than the STS and can carry 5000kg more payload, with a slightly bigger payload bay. It also required less fuel to get to orbit.

Although it carries only slightly more propellant for orbital manoeuvres, its orbital engines are significantly more powerful.

Buran and Energiya

One of the most noticable distinctions between NASA's STS and Buran, is that the Soviets placed the liquid fuel engines, not on the back of the shuttle, but on the base of the centre fuel tank. There are also four of them, rather than three on the American version. These rocket motors were already being designed for other rockets and could be converted for the use. These engines are disposable, destroyed along with the fuel tank on each launch. This suited the Soviet space program better for several reasons. Firstly, designing and building re-usable engines is difficult and expensive. The three engines on the STS have caused many headaches for NASA, as they require enormous amounts of maintenance. At the time, the Soviets lacked the expertise to make these engines reusable, but were quite proficient at disposable engine design and construction. Secondly, the Soviet design can be launched without the orbiter.

The launch system, comprising the fuel tank and external solid fuel boosters is known as Energiya. It has four boosters, rather than the two of the NASA design. The Soviets designed it to have its own guidance system, so that it can launch without the shuttle, although why anyone would want to is difficult to imagine.

Flight

At 3:00 GMT on November 15, 1988 Buran lifted off on its maiden flight. It completed two orbits and re-entered. At 6:25 GMT it landed in Tyuratum. Its flight was limited to two orbits due to a lack of memory in the flight computer.

The flight was unmanned. This was done for two reasons. The life support system was untested and the computer displays in the cockpit had no software, so the crew would not have been able to fly it. The computers could not generate a display for the pilots. NASA's STS has never flown unmanned, its first flight had the minimum crew of two, a commander and a pilot.

Analysis

The Buran flight was a huge technical success. The autopilot was able to correct for a 34 mph cross wind on landing, which is high enough for NASA to divert to their alternate landing site in White Sands.

Buran lost significantly fewer insulating tiles on re-entry, possibly due to the wing design. On the first flight of the NASA orbiter, more than 20 tiles were found to have been lost, some on take off. Buran lost only five out of more than 38,000.

Two other orbiters were planned and construction had begun on them. The second was called Ptichka, meaning 'Little Bird'. Neither of these was completed and both were dismantled.

The End of The Buran Program

Buran never flew in space again. Political will faded, and a report from the Russian space agency showed that Buran was actually an enormously expensive way of getting into space. Funding was cut and in 1993, the Buran project was officially cancelled, although mothballing operations were being performed long before this. Buran did make one final curtain call. On 13 May 1989, it flew attached to the back of Antonov An-225 'Mriya' which was designed specifically for this task and is the heaviest, most powerful and in most aspects also the biggest plane ever built. Both An-225 and Buran visited the Paris Air Show a few days later. This is again a method borrowed from the Americans, who fly their shuttle on the back of a modified Boeing 747.

References

• Buran and STS comparison
• Buran sitting on its An-225 transport
• Technical drawings of Buran and Energiya
• Artist's impression of Buran in space
• Three elevations of Buran and Energiya