The Soyuz-2.1b launch vehicle with the Progress MS-35 cargo ship successfully launched from Baikonur after a third stage malfunction was rectified. The first two stages were powered by serial RD-107A and RD-108A engines manufactured by the Samara-based ODK-Kuznetsov enterprise: both types operated normally during the September 16 launch.
The RD-107A on the first stage develops a thrust of 85.6 tf at Earth, and its specific impulse in vacuum reaches 320.2 s. The second stage is equipped with RD-108A engines with a thrust of 80.8 tf and a specific impulse of 320.6 s. Engines of these families are installed on the first and second stages of all Soyuz family launch vehicles.
The launch took place from site No. 31 at 16:34 Moscow time. Progress MS-35 headed to the ISS with a cargo weighing over 2.5 tons — fuel for refueling the station, water, oxygen, food, medicines, hygiene products, and equipment for scientific experiments. Docking with the ISS is scheduled for September 19.
For ODK, this launch continues the long-term operation of the RD-107/RD-108 family of rocket engines. The company states that more than 12,000 serial rocket engines have left its production lines, and over 2,000 space rocket launches have been carried out using them.
A separate part of the Progress MS-35 cargo included materials for the Teledroid experiment. An exoskeleton, an operator's workstation designed to control a humanoid robot, was sent to the ISS; the robot itself is expected to arrive on the next cargo ship.