THE ZENIT FAMILY

The unification of the first stage of the medium-lift 11K77/Zenit rocket with the strap-on boosters of Energiya was a sound engineering decision, allowing the RD-170 engine and associated systems to be thoroughly tested in flight before the maiden mission of Energiya. However, the 11K77 was far more than just a test bed for Energiya, having been conceived at KB Yuzhnoye long before Energiya as a rocket in its own right to orbit a new generation of heavier satellites. Before being unified with Energiya’s first stage, the 11K77 had already evolved from an R-36M derived launch vehicle with storable propellants to a LOX/kerosene rocket with a clustered first stage (see Chapter 2). The 11K77 not only pre-dated Energiya, but has now long outlived it, continuing to fly today both in its two-stage domestic version and the three-stage Sea Launch version. Along with the RD-180 engine, it is undoubtedly the most tangible spin-off of the Energiya-Buran program, with a bright future ahead of it more than 20 years after its first flight. Not only did Zenit serve as a pathfinder for Energiya, it was also supposed to be the central component of its own rocket family, including a downsized version (11K55) and several heavier variants (11K37), none of which ever made it off the ground.