To give the ability of launching manned space vehicles "Soyuz" of a greater mass comparing to "Vostok" (initially 5.8 t and then 6.5 t instead of 4.8 t.), the "Vostok" had to be modified. Mainly, stage III was a matter of concern. Stage E on LV "Soyuz" was replaced with stage I with LV "Molniya". Further modifications of launch vehicles derived from rocket R-7 were made by the Central Specialized Design Office (D. I. Kozlov) to which all documentation on the R-7 derived rockets was passed on.