BURAN PROPULSION SYSTEM AND VSU TESTING

Testing of Buran’s ODU propulsion system was the prime responsibility of the so-called Primorskiy Branch of NPO Energiya in the Leningrad region on the shores of the Gulf of Finland. This was set up in 1958 as a branch of Glushko’s OKB-456, mainly to test engines with exotic propellants such as the RD-301 fluorine/ ammonia engine destined for a Proton upper stage. When OKB-456’s successor KB Energomash merged with TsKBEM in 1974 to form NPO Energiya, the Primorskiy Branch became part of the new conglomerate and remained subordinate to it even after Energomash regained its independence in 1990. Its first assignment as part of NPO Energiya was to test the RD-120 engine for the second stage of Zenit. The old RD-301 test stand was refurbished for a series of horizontal test firings of 11D58M engines for the Proton rocket’s Blok-D upper stage in 1978­1982, which were probably seen as precursors to similar tests with the Orbital Maneuvering Engines (DOM or 17D12) for Buran. Between May 1985 and Septem­ber 1988 six 17D12 engines underwent 114 horizontal test firings lasting a total of 22,311 seconds.

Meanwhile, in 1981 construction had begun of a new vertical test stand called V-1 to test complete ODU engine units called EU-597, containing not just the 17D12 engines, but also thrusters and verniers. The first such ODU unit (nr. 10S) began testing in June 1986 but was destroyed in a fire in February 1987, seriously damaging the test stand. V-1 was refurbished for a series of tests with a new unit (nr. 12S) between September 1987 and April 1988 that underwent the complete ODU firing program planned for the first Buran mission. Those tests uncovered a problem that would delay the Buran flight for several months (see Chapter 7). More tests were conducted with unit nr. 31L between June and December 1988 and unit nr. 11S between January 1991 and March 1993. After cancellation of the Energiya-Buran program the unit was mothballed and eventually removed from the test stand. The 17D15 thrusters and 17D16 verniers apparently also underwent individual tests at Nllkhimmash near Zagorsk. Test firings of the ODU integrated in Buran were conducted at Baykonur’s test-firing platform [14].

The Auxiliary Power Units (VSU) underwent a test program at the IS-104 and IS-105 test stands of Nllkhimmash, which included simulated hydrazine leaks to test the fire suppression system. The VSU hydrazine tank was put to the test in simulated weightless conditions aboard an Ilyushin-76 aircraft and also at various ^-levels at Star City’s TsF-18 centrifuge. The VSU test program culminated in the units being installed on Buran and activated at the Buran test-firing stand at Baykonur.