Long March 3C with BD-2-G7 on atop launched !

Yesterday at 15:30 GMT Chinese rocket Long March 3C delivered to orbit BD-2-G7 navigation satellite.

Rocket was launched from Xichang Satellite Center from Launch Complex 2 at 15:30 GMT (23:30 local time). It was 229th launch of Long March rocket and 23rd launch of Beidou satellite in the history of program. Satellite belongs to second generation of Beidou system spacecrafts which is also known under Compass name. System is developed by China since first conceptual works in 1983 and is planned as competitor for GLONASS and GPS; it was started as local navigation system operating in China and it was gradually extended to be offered in Asia. At the moment it is covering with its range 120° of Northern Hemisphere, in 2020 it is planned to reach global coverage with constellation of 35 satellites. At the moment system is used by China and Pakistani armed forces where it won competition with GLONASS and GPS. Parameters offered commercially by Compass is accuracy at 10 m with speed of 0.2 m/s; accuracy for military purposes is higher with assumed accuracy up to 10 cm. Navigation signal is transmitted using following frequencies: 1195.14-1219.14 MHz, 1256.52-1280.52 MHz, 1559.05-1563.15 MHz and 1587.69-1591.79 MHz. BD-2-G7 launch was confirmed by USSTRATCOM; individual number for satellite is 41586, orbit parameters were confirmed as 219 km x 34574 km with inclination at 19.28°.

Satellite launched yesterday has codename BD-2-G7 and is seventh satellite from second generation of Compass satellites. First BD-2 satellite was launched in 2009 but successfully operating BD-2 satellite was launched in 2010. BD-2-G7 like every BD-2 satellite was launched on atop of Long March 3C rocket from Xichang Satellite Center. BD-2 satellites are manufactured and designed by China Association for Science and Technology basing on DFH-3 bus. Weight of the BD-2-G7 is approximately 4600 kg with estimated operational life at 8 years. It is equipped with two deployable solar arrays and onboard batteries providing 6800 w of power. Propulsion is thruster able to generate 490 N of thrust. Fuselage of satellite before deploying solar arrays has 2.2 m x 1.7 m x 2.0 m. Payload is dedicated strictly to supporting Beidou navigation; it includes phased array antenna for navigation signals transmission, an S and L Band dish antenna, a C band ranging antenna and a laser retroreflector for orbit positioning.

Long March 3C rocket, developed and manufactured by China Academy of Launch Vehicle Technology is operating from Xichang Satellite Center from Launch Complex 2. Rocket is long for 54.8 m with diameter at 3.35 m and mass of 345000 kg. Payload capacity for GTO missions is up to 3800 kg and could be extended to 3900 kg in C/E version. C/E is slightly extended comparing to C version; it has longer boosters and first stage with larger fuel tanks. Since maiden flight performed in 2010, rocket was used for 13 missions with success ratio at 100%.  It is equipped with two boosters fueled with N2O4/UDMH and powered with single YF-25 engine each. Thrust of each booster is 740.4 kN and fuel load is 41100 kg. First stage is powered by 4 YF-21C liquid fueled engines each burning 171800 kg of N2O4/UDMH. YF-21C engines are generating thrust at 2961.6 kN. Stage is long for 23.27 m with diameter at 3.35 m. Second stage is powered by combination of central YF-24E (742 kN) and four stabilizing YF-23C (47.1 kN) engines fueled with N2O4/UDMH. It has diameter at 3.35 m and length of 12.92 m and its tanks hold 49400 kg of propellant.  Third stage is fueled with 18200 kg of LH2/LOX and its propulsion is based on single YF-75 engine generating thrust at 167.17 kN. Third stage diameter is slightly smaller and is exactly 3 m in diameter with 12.387 m of length.