Soyuz-U2

The Soyuz-U2 was a Soviet, and later Russian, expendable carrier rocket derived from the Soyuz-U. Its primary distinction was the use of Syntin, a high-performance rocket fuel, in its single-chamber RD-120 engine of the second stage (Block I). Syntin offered a higher energy density than the standard kerosene-based fuel (RP-1) used in the Soyuz-U's second stage engine (RD-110). This improved performance allowed for heavier payloads to be launched into orbit.

The Soyuz-U2 was developed to provide increased lift capacity for specific missions, mainly for launching Zenit reconnaissance satellites. The first launch occurred on December 23, 1982, and the final launch took place on February 11, 1995. After a relatively short operational history, the production of Syntin was discontinued due to high costs and environmental concerns. Consequently, the Soyuz-U2 rocket was retired.

The overall design was similar to the Soyuz-U, with the addition of the more powerful second-stage engine. It was launched from the Baikonur Cosmodrome in Kazakhstan. Following its retirement, the Soyuz-U became the workhorse launch vehicle, and later the Soyuz-2 family of rockets further improved upon the original designs.