276th mission by Arianespace finished with success – both FM10 & FM11 Galileo satellites reached their planned orbit.

European Space Agency put this mission in the addition to Galileo launch schedule for 2016 thanks to decision of European Commission. Both satellites were contracted for OHB System as main contractor and for SSTL as payload contractor. ESA signed agreement with OHB-System GmbH and SSTL in 2010 for 14 satellites and next in 2012 for additional 8 spacecrafts. FM10 and FM11 are 13th and 14th satellites launched under Galileo program and first two of six planned for 2016.

Launch of the Soyuz-2.1b was scheduled for 08:48 GMT from ELS launch pad in Guiana Space Center. Launch Readiness was announced on Monday, 23 May 2016 and today early in the morning, at 05:26 GMT fueling process of the rocket was started. RG1 and LOX fully filled tanks of the Soyuz-2.1b at T-90′ (07:17 GMT). Starting countdown was planned for 6 minutes 10 seconds before start and begun according to plan. Previous weather forecasts which predicted heavy rain luckily seemed to be missed and weather in French Guiana let to set everything for “go” ten minutes before liftoff. Satellites remain inside ST fairing on atop of Fregat upper stage: they were installed symmetrically along center of the fairing. Between satellites special dispenser was attached which will deploy satellites to the opposite sides. ST version of the payload fairing is 4.1 m in diameter and almost 11.5 m of length. At T- 5′ start key was inserted and Fregat upper stage was switched to internal power. At T-00’34” service tower was retracted and at T-00’17” engines were ignited. Four RD-107A on boosters and single RD-108A in core started to work and reached at T-00’01” full thrust. At 08:49 GMT, one minute later then it was planned, Soyuz-2.1b with two Galileo satellites started to rise over ELS launch pad. At T+01’00” rocket reached altitude of 9 km and speed of 1440 km/h. At T+1’58” boosters separation was performed on altitude of 43 km, when rocket was flying with speed of 6480 km/h. Payload fairing was jettisoned on altitude of 113 km during flight with speed of 9576 km/h at T+3’41”. At T+4’47” first core stage was turned off and third stage started its RD-0124 engine; two seconds later it was separated from the second stage. Soyuz-2.1b started to enter in the range of CNES naval transportable control station remains on Atlantic. At T+4’49” stages were separated on altitude of 148 km with speed at 13608 km/h. Separation was performed 450 km from Guiana Space Center. At T+9’34” Fregat upper stage separated from the third stage and started ballistic flight on altitude of 174 km with speed at 26604 km/h. At T+10’22” Fregat started its engine for the first time during this mission. S5.92 engine, main propulsion of Fregat, was turned off at T+23’37” after reaching speed of 33660 km/h on altitude of 543 km. At T+03h38’35” Fregat performed second burn which lasted to T+03h42’57” during which it reached altitude of 23500 km. It was last burn before separation of the satellites. At least, at T+3h47’58” Fregat deployed both satellites on MEO circular orbit of 23567 km. Next satellites will start to reduce their speed (which was in the moment of deploying 9504 km/h) and gradually reach designated orbit with altitude of 23222 km with inclination at 57.394°.