THE FIRST FLIGHT OF ENERGIYA 6S becomes 6SL

According to original flight plans drawn up in the 1970s, Energiya was to begin its test flights in 1983 with two suborbital missions carrying full-scale Buran mock-ups, followed in 1984 by the first launch of an unmanned flightworthy orbiter [10]. By the early 1980s those timelines had changed significantly, as had the flight plans them­selves. The idea was now to launch an unmanned Buran into orbit on the first mission of Energiya (rocket 1L) following the completion of fueling tests with the 4M core stage and pad test firings of the 5S and 6S vehicles.

The original plan for 17 pad test firings lasting a total of 3,700 seconds was quickly laid to rest. Satisfied with the results of the 5S test firing on 25 April 1986, the MVKS decided on 5 May to significantly curtail the test-firing program and conduct just one more test firing with the 6S vehicle to reach an accumulated pad burn time of 423 seconds prior to the maiden launch of Energiya. The plan was to turn the remaining 30-second test into a combined test firing of the four RD-0120 core stage engines and the four RD-170 strap-on booster engines, something which would also have been the culmination of the original test-firing program. Consideration was also given to strapping the OK-ML1 Buran mock-up to the core stage for that test.

However, as these events unfolded, an alternative proposal from Energiya chief designer Boris Gubanov had been steadily gaining ground. That was to skip test firings of the 6S vehicle altogether and turn it into a flightworthy rocket for a test mission that would precede the flight of Energiya 1L with the Buran orbiter. In a way, it was a return to the “test-as-you-fly” philosophy so common in other Soviet space projects. Gubanov’s main argument was that if one of the test firings ended in a cataclysmic explosion, it would take two to three years to rebuild the unique test stand. Not only was the UKSS later supposed to become a launch pad, it would also continue to serve as a test stand for core stages and strap-on boosters to be flown on operational Energiya missions.

The risk of an accident would be even higher if the strap-on boosters were going to be involved in the tests as well. Rather than test-fire the rocket on the ground, Gubanov argued, it would simply be test-fired in flight. The minimum mission objective would be to fly safely for at least 30 seconds, allowing the rocket to reach a safe distance from the test stand. This would achieve the same goal as a combined 30-second ground-based test firing of the core stage and strap-ons, without running the risk of wiping out the UKSS.

The idea originated in early 1984, but it would take Gubanov almost two years to get it accepted. Gubanov made his first overture to the highest authorities in early 1985, putting forward the idea to Grigoriy V. Romanov, who as the Central Com­mittee Secretary for Defense Matters was the highest political figure in charge of the space program. However, Romanov was not convinced, electing instead to divert more resources and personnel to the space station program with the goal oflaunching the Mir core module by the next Party Congress in February 1986. The proposal initially also met with stiff opposition from NPO Energiya general designer Valentin Glushko, who at one point even said that “one wouldn’t come up with such an idea even when drunk.’’ Also opposed to the plan was launch pad chief designer Vladimir Barmin, whose organization (KBOM) would now have to turn the UKSS into a launch pad much earlier than expected. Also favoring a full-scale ground-based test firing of both the core stage and the strap-on boosters was the military community.

However, as the months progressed, events gradually turned to Gubanov’s favor. In July 1985 Romanov, once considered a leading candidate to become the next General Secretary of the Communist Party, was removed from the Politburo and from his post as Secretary for Defense Matters as part of a Party management shake-up following the election of Mikhail Gorbachov as General Secretary in March of that year. By the end of the year Gubanov had garnered support from Minister of General Machine Building Oleg Baklanov (also the head of the MVKS), who in turn convinced his ally Glushko. On 2 January 1986 Baklanov flew to the cosmodrome with a large number of leading space officials, giving them the order not to return home until an Energiya had been launched.

Long before getting the needed political support, Gubanov had secretly been making arrangements to convert the 6S core stage into a flight vehicle called 6SL (“L” standing for “flight”). He had already asked the people of the NPO Energiya Volga Branch to study this possibility during a visit to Kuybyshev in November 1984. An official industry order followed on 16 August 1985 and allowed engineers to “cannibalize” parts of the first flight-rated rocket (1L) to speed up launch prepara­tions. As a result, all elements of the core stage were in place at Baykonur by the beginning of 1986.

A key argument in getting approval for the 6SL launch was that Buran was suffering more and more delays, further pushing back the launch of Energiya 1L. An early demonstration launch of the 6SL vehicle would not only be a boost to the team, but could also help convince the country’s political leadership of the program’s feasibility. With a new wind beginning to blow through Soviet politics in the mid – 1980s, the Energiya-Buran program was finding itself on increasingly shaky ground and was in dire need of a major success. Somehow, Gubanov’s original argument for the launch—namely, to reduce the risk of a catastrophic explosion on the UKSS— had moved to the background and a 30-second combined static test firing of the 6SL core stage and strap-ons remained on the agenda even after the successful test firing of 5S in April 1986. The Military Industrial Commission set up an independent commission headed by Konstantin V. Frolov, the Vice-President of the Academy of Sciences, to look into the need for additional test firings, but this failed to give a clear-cut recommendation. However, a continuing string of successful Zenit launches and test firings of Blok-A and Zenit first stages at Nllkhimmash gradually made the test firing redundant. Energiya was ready to fly [11].