INSAT-3DR – finally on orbit !

Indian meteorological satellite, INSAT-3DR, was launched today on atop of GSLV Mark II from Satish Dhawan Space Center T-1 launch pad.

INSAT-3DR is replacement satellite for previous INSAT spacecraft; launched on July 25 2013 on atop Ariane 5 ECA, Insat-3D, suffered for anomaly during deploying one of its solar panels. Fortunately specialists and engineers from ground control center managed to bring satellite to operational life, but ISRO (Indian space agency) decided to intensify efforts to create replacement for INSAT-3D. This time second from three planned INSAT satellites was planned to be launched with Indian rocket, GSLV, to GTO orbit with GEO as designated orbit. Final orbital parameters are: altitude of 36000 km with designated orbital slot at 74° east.

Originally planned for 10:40 GMT launch was delayed for around 40 minutes. Mission covered delivering INSAT-3DR to altitude of 250 km. At 11:17 GMT automatic countdown sequence started. At 11:21 GMT weighing 415 t and long for 49 m rocket started to lift off. At T+1'40" rocket reached altitude of 30000 m. Nine seconds later first stage of GSLV Mark II, equipped with solid fueled with HTPB S139 engine, stopped providing 4600 kN of thrust. All four liquid fueled with N2O4/UDMH boosters (each giving 760 kN of thrust) powered by L40H engines were shut down at T+2'29". Three seconds later, at T+3'00", rocket passed 90 km of altitude with speed of 9700 km/h; few seconds later it reached space after crossing Karaman’s line. At T+2'31' first and second stage were separated. Second stage was fired at T+2'31" and its single GS2 Vikas liquid fuel (N2O4/UDMH) engine with thrust at 800 kN started to work. Payload fairing long for 7.8 meters with diameter at 3.4 meters was jettisoned at T+3'48". Vikas engine was burning until T+4'30" when it was shut down. Three seconds later it was separated from upper cryogenic stage, which was ignited at T+4'35". Fueled with LH2/LOX CE-7.5 engine started to provide 75 kN of thrust. At T+16'15" upper stage was shut down and at T+17'23" satellite was deployed on altitude of 240 km.

INSAT-3DR is meteorological and SAR satellite designed by ISRO basing on I-2K bus. Satellite weighs 2011 kg and will remain on orbit for at least ten years. Selection of its main onboard devices was determined by purpose of the satellite; spacecraft is equipped with Data Relay Transponder for receiving data from the ground on C band; along with Search and Rescue Transponder device both instruments will serve as relay for alerts and data from ground (DRT) and sea (SAR). Next SAR and DRT will transmit data and signals to mission control center. Sounder operating on 18 channels (from short wave infrared to long wave infrared) will provide data on atmosphere, humidity and ozone level. Multi-spectral imager working on 6 channels will provide detailed images every 26 minutes to give necessary data on winds, clouds or sea temperature. INSAT-3DR is powered by two deployable solar arrays, which are providing peak power of 1700 W (onboard instruments requires 1164 W). Satellite weighs 2011 kg with dry mass at 907 kg and propellant mass at 1250 kg. Apogee Kick Motor which will be utilized for reaching GEO orbit is providing thrust at 440 N. Frame of the satellite is made of aluminum alloy, carbon fiber and reinforced plastics. Satellite will be controlled from mission control center located in Bangalore.