Space booster stage flying on Proton and Zenith, Blok D, is also derived from the fifth stage in the Moon expedition stack. Its engine is also the predecessor o

Space booster stage flying on Proton and Zenith, Blok D, is also derived from the fifth stage in the Moon expedition stack. Its engine is also the predecessor of the main engine of Buran. Lunar spacecraft technology helped with later creation of space probes, like Vega, and flying today space booster Fregat.