Buran’s role in space station operations

Although Buran figured prominently in plans for both Mir and Mir-2, there are no indications it was ever supposed to replace traditional transportation systems such as Soyuz and Progress. The idea was that it would be used in parallel with those systems for missions requiring its unique capabilities, such as assembly of large structures, swapping out of modules and delivery and return of large pieces of equipment. While Buran could have made it possible to reduce the number of Soyuz and Progress missions, these vehicles would have continued to play a crucial role in Soviet space station operations. This also explains why the Russians never stopped improving Soyuz and Progress during the development of Buran.

In fact, the International Space Station (ISS) is now pretty much operated as the Russians had set out to do with Mir and Mir-2, being serviced by a combination of large shuttles and smaller capsule-type vehicles. The ISS itself is clear proof that it is impossible to operate a space station with large shuttle vehicles alone. Although such vehicles can deliver larger crews and more supplies than capsule-type spacecraft, it is not economically justified to use them for dedicated crew rotation and resupply missions. Ideally, these tasks should be combined with shuttle-unique assignments and not be seen as mission objectives in themselves.

The biggest problem with Shuttle/Buran-type vehicles is that they can only stay docked to a space station for several weeks at most until their consumables run out. Vehicles like Soyuz and Progress can be largely deactivated after docking to a station and remain attached to it for months on end. This means they are always available for reboost and refueling operations when needed and—crucially for crew safety—can always immediately return a resident crew back home if an emergency situation arises. NASA had originally planned to service Space Station Freedom solely with

the Space Shuttle and leave crews on board in between Shuttle missions. Only after the 1986 Challenger disaster did it dawn on the agency that it would be dangerous to have crews on the station without a lifeboat attached. NASA then found itself scrambling to find a US contractor capable of building a station lifeboat at short notice. Fortunately enough for NASA, political changes in the USSR allowed the agency to adopt Soyuz as a lifeboat for Freedom in 1992 and the vehicle continued to serve in that role as part of the ISS.

The simultaneous operation of large shuttles and capsules also provides redun­dancy. One vehicle can continue to service the station in case the other is grounded. This was vividly demonstrated by the 2003 Columbia accident, after which Soyuz and Progress vehicles served as a lifeline for the station. One can only imagine what things would have been like if both the Space Shuttle and Buran had been around for ISS operations. Having been built to the same specifications as the Shuttle, Buran could have continued ISS assembly work during the Shuttle’s standdown. Of course, this is no more than wishful thinking, because the very conditions that lay at the foundation of Buran’s downfall enabled the creation of the ISS.