'Union‑2.1c',[a] GRAU index: 14A15)[3] known early in development as the Soyuz‑1, was a expendable Russian small-lift launch vehicle.

It is derivative of the Soyuz‑2 but utilizing a single core stage (no boosters) built around the powerful NK-33 engine, 50-year-old refurbished remnants from the Soviet N1 moon rocket.

Most missions will use a Volga upper stage to transfer the payload from an initial parking orbit to its final destination.

The Volga is derived from the propulsion system of the Yantar reconnaissance satellite, and was developed as a lighter and cheaper alternative to the Fregat that is used on many Soyuz‑2 missions.

The Soyuz‑2.1v was designed to serve lighter payloads with a payload capacity of 2,850 kg (6,280 lb) to a 200 km (120 mi) circular low Earth orbit with an inclination of 51.8° from Baikonur, and 2,800 kg (6,200 lb) to a 200 kilometre orbit at 62.8° from Plesetsk.