Groza and Energiya-M

In the course of Energiya’s history several studies were made of configurations in which the core stage was flanked by just two strap-ons, providing payload capacities of between about 30 and 60 tons. The first version, called RLA-125, was proposed in 1976 and another one known as Groza (“Thunderstorm”) appeared in the mid-1980s. Groza, using a standard core stage with four RD-0120 engines and two strap-ons, had a reported payload capacity to low orbit of up to 63 tons. The Cargo Transport Container strapped to the side would be a downsized version of that developed for Buran-T. Groza required virtually no modifications to the existing Energiya pads. All that needed to be done was to bolt the strap-ons more firmly to the pad because the rocket would be more susceptible to high winds. Because of this, launch weather rules were also tightened.

On 25 December 1984 the Soviet government released a major decree on rocket and space systems to be developed in the period 1986-1995. One of these was planned to be a series of rockets with payload capacities between 30 and 60 tons, although it is not clear what payloads exactly were being considered. Three systems were adopted for parallel studies: a modernized version of the Proton rocket, several heavier versions of the Zenit (11K37), and Groza. As mentioned earlier, these boosters were to use a standardized series of cryogenic upper stages, Shtorm for Proton and Vikhr for the 11K37 and Groza.

The preliminary design for Groza was completed in December 1985. However, on 18 August 1988 the Ministry of General Machine Building ordered NPO Energiya to modify the rocket in order to make it compatible with more realistic payloads of between 25 and 40 tons. This made it necessary to reduce the number of RD-0120 engines to one or two and hence make the core stage smaller. The first idea was to reduce the diameter of the core stage to 4.1 m or 5.5 m and lower the propellant mass to between 200 and 450 tons. However, since this would have required different manufacturing techniques, it was decided to retain the standard Energiya core stage diameter of 7.7 m. By late 1989 engineers were focusing on a version with one RD-0120 engine and a propellant mass of around 240 tons. With the core stage (called Blok-V) only about half as high as that of Energiya, the payload had to be stacked on top rather than strapped to the side. At the intersection between the core stage and the payload bay the rocket would taper off to a diameter of 6.7 m, the same as that of the 14S70 Cargo Transport Container of Buran-T. With a length of 25 m,

the payload bay was probably almost identical in dimensions to the Cargo Transport Container for Groza. The concept was approved by the Council of Chief Designers on 19 July 1990. Initially called Neytron (“Neutron”), the new rocket eventually became known as Energiya-M.

Four configurations were considered for the payload section, one in which the satellite would occupy the entire bay and have its own engine system (N-11) and three where the satellite would be attached to various upper stages (N-12, N-14, and N-15).

The N-12 was a Blok-DM modification with an engine known as the 11D58MF and was also planned for use on Zenit, Proton, and the original Angara. It allowed the rocket to place 29 tons into low Earth orbit or up to 3 tons into geostationary orbit. The N-14 was a Blok-DM modification with the standard 11D58M engine and was identical to the second stage of the 204GK upper-stage combination planned for Buran-T. It was capable of delivering a 5.5-ton payload to geostationary orbit. The N-15, able to launch 6.5 tons into geostationary orbit, was a LOX/LH2 upper stage but no further information on this is available. It is known that in 1992 work got underway on a LOX/LH2 upper stage known as Yastreb carrying the RO-97 engine of KBKhA. This stage was primarily intended for Proton, Zenit, and Angara, but with slight modifications could also be mounted on Energiya-M. However, it was smaller than the N-15 and also had its propellant tanks configured differently.

As early as 1990 a mock-up of Energiya-M was ready for tests at Baykonur. It was placed both on the UKSS pad and Energiya-Buran pad 37. It was only afterwards, on 8 April 1991, that the government issued a decree ordering NPO Energiya, KB Yuzhnoye, and KB Salyut to come up with competing proposals for boosters in the 25 to 40-ton payload range. This basically was a repeat of the order given in the 25 December 1984 decree, although in a somewhat lighter payload class. KB Salyut and KB Yuzhnoye had apparently also been optimizing their Proton and 11K37 designs. Eventually, on 6 July 1991 the Ministry of General Machine Building opted for Energiya-M. Between 1991 and 1993 preparations were made for starting production of flight models.

During that period, NPO Energiya worked out plans to launch a 30-ton space – plane (OK-M2) atop the rocket and also to turn the two strap-ons into reusable flyback boosters, something which appears to have been studied as early as 1989. Another idea was to launch the rocket from an ocean-based platform near the equator. This would not only allow Energiya-M to loft heavier payloads, but would also resolve the political problems associated with flying it from Baykonur, which became foreign territory after the collapse of the Soviet Union. One exotic mission considered for the ocean-launched Energiya-M was to deposit radioactive waste into heliocentric orbits, eliminating the risks involved in launching such dangerous payloads over populated territories. These studies formed the basis for the creation of the international Sea Launch venture, which would eventually use the three-stage Zenit rocket.

Despite the fact that Energiya-M used existing hardware and infrastructure and outperformed rockets like the Titan-4 and Ariane-5, it was ahead of its time. At the time there was simply no demand for the types of satellites that the rocket could place into orbit. On 15 September 1992 the Russian government started yet another com­petition to develop a family of even lighter rockets, which would eventually evolve into the Angara series. By late 1993 government funding for Energiya-M was stopped, with Russian Space Agency officials stating there was no demand for the rocket on the market. The following year NPO Energiya made an ultimate attempt to attract Western customers to Energiya-M and other Energiya variants, but to no avail. The prototype Energiya-M still stands today inside the Dynamic Test Stand at Baykonur [66].