Fourth time was lucky for Arianespace and ESA. Sentinel-1B after breathtaking launch reached designated orbit and confirmed its perfect condition.
Arianespace gave all of us beautiful spectacle with spectacular VS14 flight, first launch of the Soyuz-2.1a from Guiana Space Center in 2016. After two attempts were halted due the poor weather condition and third was cancelled after problems with Inertial Measurement Unit (IMU). This time everything went perfect. Weather, which still seemed to be not ideal with heavy clouds and wind, did not interrupt launch procedure. Soyuz rocket with Sentinel-1B encapsulated with MICROSCOPE scientific satellite belonging to CNES and three Cubesat satellites (OUFTI-1, E-st@r-2 and AAUSAT-4) chosen under program “Fly your satellite” was fueled at 20:33 GMT. It is worth to mention how payload was mounted inside fairing. On the top Sentinel-1B took its place; MICROSCOPE was placed under the Sentinel surrounded with support construction (ASAP-S with integrated deploying device for Cubesat satellites) and below three Cubesats were attached in special container.
After 19 minutes at 20:52 GMT rocket was already prepared for being switched to internal power and four minutes later countdown sequence was started. At 21:01 GMT Soyuz switched to internal power. Strongback was pushed away at T-36″ and just before liftoff, all five engines (four RD-107A on boosters and one central RD-108A engine) started to perform last engine check and gave opportunity to cancel start if something wrong would be spotted. At 21:02:13 GMT rocket started to liftoff; boosters which are set to give most of the thrust which is needed for start, would worked for about 118 s while central engine worked for 286 s. At T+51″ rocket reached speed of sound with cloud around fairing when reaching sound barrier. After all LOX and Kerosene was burned, boosters separated successfully at T+1″21″. At T+1’51” rocket reached altitude of 38 km with speed at 1,51 km/s and ground control center started to prepare for jettisoning payload fairing. At T+3’31” payload fairing was jettisoned on altitude of 125 km when rocket was flying with speed at 2,42 km/s. At T+4’47” with speed at 3,47 km/s and altitude of 198 km Soyuz performed cut off of the central engine of the second stage (boosters are considered as the first stage) after reaching distance of 417 km from launch pad to the north-east direction. At T+4’50” second stage was separated and third stage started its RD-0110 engine. At T+8’41” third stage was shut down and separation was performed on altitude of 415 km with speed of 5.77 km/s, over 1500 km from launch pad. After reaching distance of 1801 km over northern Canada on altitude of 513 km Fregat upper stage started its S5.92 engine fueled with N2O4 and UDMH, at T+9,52 km/s. Fregat and Sentinel-1B became acquired by Saint-Hubert ground station. Correct orbit altitude for Sentinel-1B -704 km – was reached at T+19’51”; Fregat entered to phase when everything is prepared for shutting down engine and deploying satellite. At T+20’19” after reaching speed of 7,57 km/s, Fregat turned his engine off and started ballistic flight scheduled for 3’20”. Fregat started performing maneuvers to set Sentinel-1b in correct position to the Sun before separation. After maneuvers Fregat was positioned with engine nozzle toward the Sun. Separation was performed at T+23’37”, on altitude of 706 km, 6977 km from Guiana Space Center. Satellite started its mission which will last for at least seven years. For Guiana Space Center it was the end work with Sentinel-1B – it became under control of ESOC in Darmstadt in Germany. At T+26′ first signals from satellite were received by ground station in Svalbard, Norway – Sentinel-1B is operating correctly. Next step in the Sentinel-1B mission is to deploy radar antenna and solar arrays which is scheduled for around 07:00 GMT.
This is not the end of busy day in Guiana Space Center. Additional payload – MICROSCOPE satellite and three Cubesats are waiting to be deployed. To perform separation it is necessary to correct orbit – Fregat started second burn at T+2h0’05”. After 11000 km of space journey, over South Indian Ocean, Fregat deployed OUFTI-1, E-st@r-2 and AAUSAT-4 at T+2h52′. After two minutes ASAP-S was separated from Fregat. Next step was starting Fregat for the third and fourth time: at T+3h32’35” and T+3h57’46”. At T+4h00’33” Fregat still continued its ballistic flight after third and fourth. Few seconds later MICROSCOPE was correctly separated on altitude of 716 km after it has flown over 13000 km. VS14 finished with success!