The Chinese have closed out 2014 with the launch of the Fengyun-2G (Fengyun-2-8) geostationary meteorological satellite using a Long March 3A (Chang Zheng 3A) rocket. The launch took place at 01:02 UTC on Wednesday from Pad LC2 at the Xichang Satellite Launch Center (XSLC).
Developed by the Shanghai Academy of Space Flight Technology (SAST) and China Academy of Space Technology (CAST), this meteorological satellite series has already seen the launch of five operational satellites.
One more satellite from the fleet is scheduled before the new Fengyun-4 satellites enters service, with the first launch of the next generation scheduled for December 2015.
Instruments on board Fengyun-2G are the DCS (Data Collection Service), the SEM (Space Environment Monitor), the S-VISSR (Stretched Visible and Infrared Spin Scan Radiometer) and the SXM (Solar X-ray Monitor).
The DCS provides operational collection services for data collection platforms (DCPs) within its field of view. The system is composed of three subsystems (Space Segment, DCP and ground-based NSMC).
The space segment of the DCS is a platform consisting of a UHF/S-band transponder, a mechanically despun S-band antenna, and UHF receive antenna. The data collection transponder operates in 401/468 MHz and the number of channels is 133, 100 of these channels are for domestic use and 33 international channels.
DCS offers a capability and a new digital S-band fax service (CCITT G3) for domestic distribution of charts and imagery. The deployed DCPs (Data Collection Platforms) in the ground segment are regionally stationary platforms installed on buoys, islands, rivers, mountains or ships.
The ground-based NSMC (National Satellite Meteorological Center) which collects and processes the DCP data and distributes it via GTS to the user community.
The SEM is a space weather instrument for charged particles at platform level. The instrument will count the number of electrons, protons and other charged particles hitting the platform.
The S-VISSR is an optomechanical system with scanning modes for normal scanning, optional scanning and single line scanning.
The telescope collects radiation during each scan and focuses it on the detectors in the focal plane using primary and secondary mirrors. The Si photodiode detector array has four elements mounted normal to the scan direction, providing 5 km wide instantaneous observation coverage on each scan line, matching the scan line width of the IR detectors with only one detector element.
The HgCdTe detectors are cooled by radiation coolers to a temperature of 100 K. A complete scan of 20º x 20º, covering the full Earth disk is obtained every 30 minutes by means of the spacecraft spin motion (100 rpm from E-W) and the step action (2500 steps from north to south) of the scan mirror.
The instrument will be used for determining the atmospheric temperature (column/profile), cloud liquid water (column/profile), cloud type, precipitation rate (liquid) at the surface, short-wave Earth surface bi-directional reflectance, sea surface temperature, ocean imagery, land surface temperature, vegetation type and land surface imagery.
FY-2G is also equipped with a solar X-ray detector for monitoring and early warning of solar flares (the Solar X-ray Monitor).
The development of the FY-2 geosynchronous meteorological satellite series began in the 1980s.
The first satellite was ready for launch in 1994. However, while the satellite was being loaded with propellant in the process facilities at the Xichang Satellite Launch Center, it exploded killing one technician and injuring 31 others.
The explosion destroyed the satellite and it took three years to prepare a replacement after the redesign of the propellant tank system.
The first FY-2 satellite to reach orbit, FY-2A Fengyun-2A (24834 1997-029A), was eventually launched by the Long March-3 (Y11) launcher from the LC1 launch platform at Xichang on 10 June 1997.
This satellite was operational until April 1998 when it began to suffer from problems. The control of the satellite was regained on December 1998, but the capabilities of the satellite were very limited with only six images a day. The satellite was later moved to 86.6 degrees East when meteorological operations ended.
In general the Fengyun-2 satellites are spin-stabilised satellites with a total mass of 1,369kg at launch (536kg dry mass).
FY-2B (26382 2000-032A) was launched at 1150 UTC on June 25, 2000 by the Long March-3 (Y12) rocket from the LC1 launch platform from the Xichang launch centre. FY-2B operated at 86.6 degrees East.
The last satellite of the original FY-2 series, FY-2C (28451 2004-042A) was launched at 0120 UTC on October 19, 2001 by the Long March-3A (Y9) rocket from the LC3 launch platform at Xichang. This satellite operated on the original location of 105 degrees East. The three first satellites are now retired.
FY-2D (29640 2006-053A) was launched by the CZ-3A (Y11) on December 8, 2006 and FY-2E (33463 2008-066A) was launched on December 23, 2008 by the Long March-3A (Y20) launch vehicle. The FY-2D is operational at 86.6 degrees East while FY-2E is operational at 105 degrees East.
Fengyun-2F (38049 2012-002A) was launched by the Long March-3A (Y22) launch vehicle on January 13, 2012.
The Long March 3A is a three-stage liquid launch vehicle, which has inherited the mature technology of the Chang Zheng-3. An upgraded liquid hydrogen and liquid oxygen cryogenic third stage has been developed to enable CZ-3A performing greater geostationary transfer orbit (GTO) capability.
The rocket is equipped with a more flexible and sophisticated control system which supports substantial attitude adjustments to orient the payloads before spacecraft separation and provides adjustable satellite spin-up rotation rate. It has paved the way for the development of Chang Zheng-3B and Chang Zheng-3C, and become the basic type of GTO launch vehicles.
The Long March 3A is mainly used for GTO missions; it also can be used for LEO, SSO and polar orbit missions, as well as dual-launch and multiple-launch missions.
The launch capability to GTO is 2,650 kg, while the lift-off mass is 241,000 kg.
The first stage and second stage of the rocket employ storable propellants, i.e. unsymmetrical dimethyl hydrazine (UDMH) and nitrogen tetroxide (N2O4), and the third stage uses cryogenic propellants, i.e. liquid hydrogen (LH2) and liquid oxygen (LOX).
On the first stage the Long March 3A uses a DaFY6-2 engine with 2961.6 kN of thrust, while the second stage is equipped with a DaFY20-1 main engine (742 kN) and four DaFY21-1 vernier engines (11.8 kN each). The third stage is equipped with two YF-75 engines (78.5 kN each).
The fairing diameter of the Long March 3A is 3.35 meters and has a length of 8.89 meters.
The launch success rate of the Long March 3A is 100 percent since its maiden flight on February 8, 1994 when it successfully launched two experimental satellites (the Shijian-4 and the Kuafu-1, a DFH-3 model). It was awarded the “Gold Launch Vehicle” title by China Aerospace Science and Technology Corporation in June 2007.
The Xichang Satellite Launch Centre is situated in the Sichuan Province, south-western China and is the country’s launch site for geosynchronous orbital launches.
Equipped with two launch pads (LC2 and LC3), the centre has a dedicated railway and highway lead directly to the launch site. The Command and Control Centre is located seven kilometres south-west of the launch pad, providing flight and safety control during launch rehearsal and launch.
Down range Tracking and Control stations of the launch center are located in Xichang City and Yibin City of Sichuan Province, and Guiyang City of Guizhou Province. Each of them houses tracking and measurement equipment for the powered phase of a launch vehicle flight.
Other facilities on the Xichang Satellite Launch Centre are the Launch Control Centre, propellant fuelling systems, communications systems for launch command, telephone and data communications for users, and support equipment for meteorological monitoring and forecasting.
During 1993-1994 Xi Chang underwent extensive modernization and expansion, in part due to the requirements of the CZ-3 launcher family and in part to meet commercial customer needs.
The first launch from Xichang took place at 12:25UTC on January 29, 1984, when the Long March (Y1) was launched the Shiyan Weixing (14670 1984-008A) communications satellite into orbit.
(Images via Chinese Media and space.skyrocket.de)