China conducted its 16th orbital launch of the year by orbiting the third satellite on its Environmental Protection & Disaster Monitoring Constellation. The Huanjing-1C (Environment-1C) satellite was launched at 23:00 UTC on Sunday from the Taiyuan Satellite Launch Center’s LC9 Launch Platform using the Long March 2C (Chang Zheng-2C) launch vehicle.
This was the 171st successful Chinese orbital launch, the 171st launch of a Chang Zheng launch vehicle, the 41st successful orbital launch from Taiyuan and the fifth launch from Taiyuan this year.
The HJ-1 satellites are a network of Earth observing satellites owned by the National Committee for Disaster Reduction and State Environmental Protection Administration of China, with the objective to establish an operational Earth observing system for disaster monitoring and mitigation using remote sensing technology and to improve the efficiency of disaster mitigation and relief.
The main application fields for China are environmental monitoring and prediction, solid waste monitoring, disaster monitoring and prediction (flood, drought, typhoon and wind damage, sand storm, earthquake, land creep, frost and grassland fires, coal fires, crop pest monitoring, ocean disaster monitoring). The program was ratified in 2003 by the Chinese authorities.
In May 2007, the China National Space Administration became the member of the International Charter ‘Space and Major Disasters’, a joint initiative that works to provide emergency response satellite data free of charge to those affected by disasters anywhere in the world.
Each member of the International Charter ‘Space and Major Disasters’ has demonstrated its commitment to use its space assets when it is most needed, when disasters of natural and human origin strike the world’s communities, or wreak havoc on the environment.
The first stage of the program is comprised of three minisatellites, usually referred to as the 2+1 constellation. The second stage of the program will consist of a total of eight spacecraft (four with optical payloads and four with SAR payloads, the 4+4 constellation). Originally, the launch of all the satellites was to be accomplished by 2012 through international cooperation.
The first stage implementation includes three small satellites (2+1 constellation). The spacecraft of the constellation are referred to as HJ-1A, HJ-1B, and HJ-1C. The HJ-1A and HJ-1B satellites were launched at 03:25UTC on September 6, 2008, by the Chang Zheng-2C/SMA (Y1) launch vehicle from the Taiyuan Satellite Launch Center.
HJ-1A is an optical satellite with a CCD camera and an infrared camera while HJ-1B is equipped with a CCD camera and a hyperspectral camera on board. Each spacecraft has a launch mass of 470 kg, with a size of 1.2 m x 1.1 m x 1.03 m, and a design life of three years.
The satellites were based on the CAST-968B bus of DFHSat (DFH Satellite Co Ltd.) of CAST (China Academy of Space Technology) and by the China Aerospace Science and Technology Corporation. Both satellites are 3-axis stabilized.
The HJ-1C satellite is a spacecraft with an S-band (ТКСА-6К collapsible mesh parabolic antenna) SAR payload based on the CAST-2000 (CAST-968B). The satellite will have a Sun-synchronous circular dawn-dusk orbit, at an altitude of 500 km, 97.3 degrees inclination and a 94 minutes orbital period, with a local time on descending node at 6:00 hours.
The satellite predicted operational life is three years. This is the first civil Synthetic Aperture Radar (SAR) system
The mass of the spacecraft is 890 kg, including 200 kg of its SAR payload. The communications of its payload data will use CCSDS standard to format compressed raw data and its auxiliary data. On board the satellite has 40 Gbit of storage capacity and the transmission is made via X-band downlink with QPSK modulation. The downlink data rate is of 2 x 160 Mbit/s.
Power supply is made by using a solar array with 7.5 m2 using GaAS/Ge solar cells capable of delivering a power of 1.1 kW (BOL) and 0.8 kW (EOL). Power is stored on two batteries (40Ah).
The S-band SAR instrument was developed with the assistance of NPO Mashinostroyenia & Vega Corp. from Russia. The SAR instrument has a 3.13 GHz (S-band) center frequency, corresponding to a wavelength of 9.6 cm, giving a spatial resolution of 20 meters, with a swath width of 100 km.
The SAR instrument will be capable of a two mode operation: Scan Mode and Strip Mode. On Scan Mode it will be able to get a 15 to 25 meter resolution with a swath of 95 to 105 km. The Strip Mode it will be able to get a 4 to 6 meter resolution with a swath of 35 to 40 km.
Other satellites were launched together with Huanjing-1C, the XY Xinyan-1 and the FN-1 Fengniao-1A/B pair.
The Xinyan-1 was build by the Aerospace DFH Development Limited of Shenzhen, the recently established spin-off of CAST’s mini-satellite department. The small satellite will test various components such as China-built microwave switches, a lighter user communication terminal and more accurate thermostats to be used of future satellites.
Also known by NewTech-1 (New Technology Demonstration Satellite), the XY-1 is the first new space technology in-orbit demonstration project developed by enterprises in China and used for in-orbit test demonstration of many new technologies.
The FN-1 Fengniao-1A/B (HummerSat-1) satellites represent the first realization of a new generic micro/minisatellite development of DFHSat (DFH Satellite Co. Ltd.).
The overall objective of the mission is to provide a technology demonstration as well as to test observation capabilities within the spacecraft class of 80-250 kg of total mass envelop (micro/minisatellite), for a number of different missions and applications, including support scenarios of constellations and formation flight (with intersatellite crosslink, relative navigation, guidance and control).
The FN-1 mission concept consists of two satellites, the FN-1A with a launch mass of about 160 kg, as the principal spacecraft of the formation, and a microsatellite, the FN-1B with a mass of 30 kg. Both satellites are launch as a uniform body.
On orbit, FN-1B will be deployed to form a two-spacecraft formation with the main spacecraft. Both spacecraft are in contact with a crosslink for information exchange and the enactment of required orbit manoeuvres. However, all ground communications with the formation is only via the mother spacecraft.
The goal of the mission is to demonstrate the newly developed CAST-mini bus and CAST-micro bus designs in space, in particular to validate their functional capabilities and technologies introduced, and to demonstrate the capability of close formation flying technologies such as relative navigation, guidance and control, intersatellite crosslink, and command.
The Fengniao-1A uses a new modular bus concept, referred to as CAST-mini, which is of CAST-968 and CAST-2000 platform heritage. The CAST-mini bus consists of a cylindrical (octagonal) body with face-mounted solar panels and two deployable T-form solar wings, oriented in the ±Y axis.
The spacecraft body has a size of 785 mm in diameter and 1032 mm in height. Thermal control is provided by passive means (radiator) and assisted by active means (heater) when needed. The satellite has a design life of three years. It is 3-axis stabilized with an Earth-pointing orientation, providing medium pointing and pointing-stability accuracies.
Fengniao-1B is a new microsatellite development of DFHSat. The objectives are to test the new modular platform capabilities in space and to use the spacecraft for formation flying demonstrations with FN-1A. The satellite bus features also an octagonal shape (as the mother spacecraft) with dimensions of 400 mm in diameter and 175 mm in height.
The surface-mounted solar cells (GaAs) provide an average power of ~ 5 W. Orbit and attitude control is provided with RCS (Reaction Control Subsystem) using 12 thrusters (each with 30 mN).
Relative orbit measurements between the two satellites are provided with a differential GPS (DGPS) receiver.
