(660), As with a number of other Soviet space launchers, the satellite's name was announced in the open Soviet press immediately after its first launch in 1965, and it would eventually become the public name of its launch vehicle. UR-500 rocket (a two-stage version): 6 one-chamber RD-253 engines (later RD-275). Hypergols are, however, very corrosive and toxic fuels, requiring special handling by highly-trained labor.