Soyuz-2.1a

Soyuz-2.1a is the base variant of the Russian Soyuz-2 medium-lift expendable launch vehicle, developed and built by the Progress Rocket Space Centre in Samara. It was the first Soyuz to fly with a fully digital flight control system, which replaced the analog system of earlier Soyuz rockets, weighs less, allows trajectory changes in flight and supports larger payload fairings. It also uses the upgraded RD-107A and RD-108A engines on its boosters and core stage, while keeping the RD-0110 engine on a third stage with enlarged tanks, and together the changes added about 300 kilograms of payload capacity. It made its maiden flight on 8 November 2004 from Plesetsk on a suborbital test and entered operational service in October 2006 with the MetOp-A launch. From Baikonur it lifts roughly 7,430 kilograms to low Earth orbit, against 8,670 kilograms for the later Soyuz-2.1b.