Today in the morning hours one of the less known version of Ariane 5 was launched. Version known as “ES” was launched for the sixth time from Guiana Space Center, this time with four Galileo navigational satellites: FM-14, FM-15, FM16 and FM-17. It was last mission under Galileo program this year and one from last missions by Arianespace in 2016.
Launch was performed in the morning hours local time (13:06 UTC) and was sixth mission of special version of Ariane 5 ES rocket. Designed mainly for delivering to Low Earth Orbit ESA Automated Transfer Vehicles (ATV) with supplies for International Space Station, has capacity of 21000 kg for LEO missions. This space was today filled with four satellites designed to operate under Galileo navigation system with designated MEO orbit with apogee at 22900 km and inclination at 54.57°. Four spacecrafts were result of cooperation of two contractors chosen by ESA: German OHB-System GmbH and British SSTL. First FOC was launched in 2014 and until now these weighing 716 kg with wingspan of arrays over 14 m (fuselage is cube with dimensions of 2.7 m x 1.2 m x 1.1 m) satellites are in fact only payload which has been delivered to orbit under Galileo program in last two years. OHB prepared bus for FOC series and SSTL (second contractor) was responsible for creating navigational equipment. Satellites are equipped with two deployable solar arrays and onboard batteries providing enough power during 12 years of planned operational life. Eight NARC-1 1 N hydrazine monofueled thrusters by Moog are responsible for keeping satellite on the correct orbit and are controlled by 3 axis attitude control system. Satellites are equipped with SAR additional transponder; navigational equipment are: two rubidium , two hydrogen maser atomic clocks and L band transponder for generating navigational signal.
Ninth Arianespace mission in 2016 started with begun of countdown procedure at 00:58 UTC. All test procedures along with fueling passed without any problems; weather forecasts were also favorable; at T-6′ synchronized sequence has started started. One minute later tanks filled into flight level and pressurization started. Water curtains preventing from noise were turned on and four minutes before launch guidance systems were switched to flight mode. Finally at 13:08 weighing 770 t and long for 50.5 m rocket started to raise over Guiana Space Center. Two minutes later both solid fueled EAP boosters long for 31.6 m were jettisoned and one minute later payload fairing separated. Thrust was decreased from 13000 kN at the T=0 to 1390 kN generated only by single Vulcan-2 engine in 180 t first stage long for 31 m. At T+5′ rocket was already on altitude of 137 km and was heading West over Atlantic. At T+9’15” first stage was cut off and separated from second stage powered by single 29 kN Aestus engine fueled with MMH and Nitrogen tetroxide. Weighing 1.9 t and long for 3.36 m stage started its flight to MEO. After ten minutes engine was cut off for the first time and upper stage started ballistic flight. At 16:34 UTC is resumed operating and after 6 minutes it was cut off for good. Four minutes later first pair of FOC was deployed and at 17:06 UTC last two satellites separated from upper stage of Ariane 5 ES.