Soyuz-2.1b delivers Glonass-52M satellite from Plesetsk Cosmodrome

Glonass-52M navigation satellite was delivered today on September 22, 2017, to orbit from Launch Site 43/4 at Plesetsk Cosmodrome in Northern Russia.

Soyuz-2.1b combined with Fregat-M delivered Glonass-52M to 191000 km orbit inclined  64.8 degrees toward the Equator. Satellite was correctly deployed and will join constellation of 23 operational satellites, which are virtually remaining technically unchanged since first launch in 2005. It is worth to remind that GLONASS requires 24 satellites on orbit to offer full range of services worldwide; as 13 satellites already exceeded their planned operational life it is possible that additional launches of Glonass-M spacecrafts are possible even this year.

Weighing 1415 kg Glonass-52M will replace GLONASS-M-715 satellite which was launched on December 24, 2006 and finished its service for after over a decade on June, 26, 2017. Glonass-52M will serve for at least 7 years and help in keeping GLONASS operational. Still just as all M generation spacecrafts, it was not designed for longer missions on orbit.

Glonass-M are made by Reshetnev Information Satellite Systems (NPO Prikladnoi Mekhaniki) and are equipped with L band transponder (25 channels on 1602.5625 - 1615.5 MHz and 1240 - 1260 MHz frequencies with 0.5625 MHz intervals) and 3 cesium clocks with laser ranging device. Spacecraft from M generation is powered by two deployable solar arrays and NiH2 onboard batteries providing 1250 W of power. Glonass-M series is predecessor of Glonass-K1 and Glonass-K2 satellites, which are stilled under development process delayed majorly due the American sanctions after Crimea annexation.

Launch was performed at 02:32 UTC from Launch Site 43/4 at Plesetsk Cosmodrome. just after launch rocket set its course to southeast. After two minutes of flight all four boosters separated correctly and at T+2'45" rocket jettisoned its payload fairing. Core stage of the rocket separated after third stage started to ignite its engine around T+4'45". It was operating until T+9'22" when Fregat-M upper stage was deployed. Upper stage performed series of 3 burns and deployed Glonass-52M directly on Medium Earth Orbit at T+3h30'.

Soyuz-2.1B rocket with  Fregat-M upper stage is proven launch vehicle for Glonass satellite. It was used for the first time for Glonass-M mission in 2011. It is liquid fueled (LOX/Kerosene) rocket with four strap-on boosters. Length is 46 m with mass at 308000 kg. Each booster is equipped with single RD-107A with thrust at 838.5 kN and burns 44413 kg of propellant. Core stage is powered by one RD-108A with thrust at 792.5 kN and fueled with 90100 kg of propellant. Second core stage is equipped in one RD-0124 generating thrust at 297.9 kN and if fueled with 25400 kg. For final injecting into orbit during this mission Fregat-M upper stage was used. It weighs 902 kg and takes 5600 kg of N2O4/UDMH propellant for one S5.92 engine which gives 19.85 kN of thrust. GTO payload capacity with Fregat-M upper stage is 3250 kg.