Soviet Union's other Moon Rocket: UR-700A

The regular UR-700 had a payload capacity of 151 tons to Earth orbit, surpassing both the N1 (97 tons) and the American Saturn-5 (127 tons). Additionally, Chelomei's engineers developed a larger follow-on version called Skhema “A“ (Configuration “A“), which incorporated nuclear engines. This configuration featured a solid-core nuclear reactor and increased the payload capacity to as much as 250 tons into Earth orbit. The first two stages of the UR-700 with the “A“ variant propulsion were similar to the regular UR-700. The six boosters in the first stage fed their own engines and simultaneously refueled the three boosters of the second stage. This ensured that the second stage had full tanks when it took over the powered ascent after the separation of the first stage. The “atomic“ version of the UR-700 included third and fourth stages developed from scratch, equipped with RO-31 nuclear engines (also known as RD-0411). These engines burned cryogenic liqu