Gaofen () is a series of Chinese high-resolution Earth imaging satellites launched as part of the China High-resolution Earth Observation System (CHEOS) program. CHEOS is a state-sponsored, civilian Earth-observation program used for agricultural, disaster, resource, and environmental monitoring. Proposed in 2006 and approved in 2010, the CHEOS program consists of the Gaofen series of space-based satellites, near-space and airborne systems such as airships and UAVs, ground systems that conduct data receipt, processing, calibration, and taskings, and a system of applications that fuse observation data with other sources to produce usable information and knowledge.
Although the first seven Gaofen satellites and their payloads have been heavily detailed, little to no details on Gaofen 8 and later satellites have been revealed prompting suggestions that Gaofen satellites may be dual purpose supporting both civilian and military missions.
In 2003, the China National Space Administration (CNSA) agreed with Roscosmos to share Gaofen data for data from Russia's Earth observation satellites of similar capability. This agreement was expanded in August 2021 when leaders from BRICS space agencies agreed to share space-based remote sensing data.
Notable satellites
Gaofen-5 Gaofen-5 has been lauded as the "flagship of the environment and atmosphere observation satellite in the CHEOS program". Launched on 8 May 2018 from Taiyuan Satellite Launch Center (TSLC) into Sun-synchronous orbit, Gaofen-5 carries six payloads: an Advanced Hyperspectral Imagery sensor (AHSI), Atmospheric Infrared Ultraspectral Sensor (AIUS), Directional Polarization Camera (DPC), Environment Monitoring Instrument (EMI), Greenhouse-gases Monitoring Instrument (GMI), and Visual and Infrared Multispectral Sensor (VIMS).
The Advanced Hyperspectral Imagery (AHSI) sensor payload aboard Gaofen-5 claims to be the first space-based hyperspectral imaging sensor utilizing both convex grating spectrophotometry and a three concentric-mirror (Offner) configuration. The AHSI uses spectrophotometry to measure the light spectra reflected, transmitted, or emitted by an imaged object to detect or identify objects on the ground. In civilian applications, the AHSI allows analysts to conduct environmental monitoring and resource discovery while in a military application would allow analysts to detect and identify an adversary's equipment or spot non-multi-spectral camouflage. AHSI has a 30 meter spatial resolution and 5 nanometer spectral resolution in the visible, near-infrared (NIR), and short-wave infrared (SWIR) wavelength ranges.
The Atmospheric Infrared Ultraspectral Sensor (AIUS) payload aboard Gaofen-5 is China's first hyperspectral occultation spectrometer meaning it measures the spectra of imaged atmospheric particles between the sensor and the Sun. AIUS allows scientists to monitor atmospheric circulation by tracing (water vapor), temperature, pressure, and various carbon and halogen-containing gas pollutants such as chlorofluorocarbons (CFCs), dinitrogen pentoxide, and chlorine nitrate. A Michelson interferometer, AIUS images wavelengths between 2.4 and 13.3 micrometers (near to mid-wave infrared) at a 0.3 centimeter resolution and a ±10° field of view.
Gaofen-5's Directional Polarimetric Camera (DPC) is China's first space-based multi-angle polarimetric camera. Prior to GF-5's launch, in September 2016, China had experimented with polarimetric imaging in 2016 aboard the Tiangong-2 space laboratory and launched its Cloud and Aerosol Polarimetric Imager (CAPI) aboard TanSat in December of that year. CAPI imaged clouds within 670 and 1640 nanometer channels but was restricted to fixed-angle imaging. The DPC aboard Gaofen-5 enables atmospheric spectroscopy in three polarized bands (90, 670, and 865 nm; polarized at 0°, 60°, and 120°) and five non-polarized bands (443, 565, 763, 765, and 910 nm), all wavelengths from green to near-infrared (NIR). A step motor rotates the 512 × 512 pixel charge-coupled device (CCD) imager ±50° providing a 1,850 km swath of imagery at 3.3 km resolution.
Satellites Since the program's start in 2013, the People's Republic of China has launched 32 Gaofen-series satellites with only one launch failure. Jilin-1 satellites described as 'Gaofen' are not part of the government's Gaofen series, rather are described as having high resolution (). Designation Launch date(UTC)PayloadsOrbit Orbital apsis Inclination SCN COSPAR ID Launch vehicle Launch site Status Gaofen 1 26 April 20132m PAN, 8m MSI, 4x 16m WFV MSISSO 632.8 km × 662.7 km98.1° 39150 Long March 2D Jiuquan SLC Gaofen 219 August 20140.8m PAN, 3.2m MSISSO630.5 km × 638.0 km97.7°40118Long March 4BTaiyuan SLCGaofen 826 June 2015EOSSO501.7 km × 504.5 km97.6°40701Long March 4BTaiyuan SLCGaofen 9-0114 September 2015EOSSO624.5 km × 671.3 km97.8°40894Long March 2DJiuquan SLCGaofen 428 December 201550m VIS, 400m MWIRGEO35,782.4 km × 35,806.4 km0.1°41194Long March 3BXichang SLCGaofen 39 August 2016C-band SARSSO757.9 km × 758.8 km98.4°41727Long March 4CTaiyuan SLCGaofen 1031 August 2016UnknownSSO (planned)N/AN/AN/A2016-F01Long March 4CTaiyuan SLCGaofen 1-02 31 March 20182m PAN, 8m MSI, 4x 16m WFV MSISSO 645.4 km × 649.0 km97.9° 43259 Long March 4C Taiyuan SLCGaofen 1-03 31 March 20182m PAN, 8m MSI, 4x 16m WFV MSISSO 642.9 km × 651.9 km97.9° 43260 Long March 4C Taiyuan SLCGaofen 1-04 31 March 20182m PAN, 8m MSI, 4x 16m WFV MSISSO 644.3 km × 650.5 km97.9° 43262 Long March 4C Taiyuan SLCGaofen 5 8 May 2018303km POL MSI, 0.3cm HSI, 30m HSISSO 706.2 km × 707.0 km98.3° 43461 Long March 4C Taiyuan SLCGaofen 6 2 June 2018MSISSO 641.0 km × 654.3 km97.9° 43484 Long March 2D Jiuquan SLCGaofen 11-0131 July 2018EOSSO493.1 km × 512.5 km97.6°43585Long March 4BTaiyuan SLCGaofen 10R4 October 2019UnknownSSO632.0 km × 634.4 km97.9°44622Long March 4CTaiyuan SLCGaofen 73 November 20192x 0.8m PAN, 2.5m MSISSO500.7 km × 517.9 km97.4°44703Long March 4BTaiyuan SLCGaofen 1227 November 2019SARSSO634.4 km × 636.5 km97.9°44819Long March 4CTaiyuan SLCGaofen 9-02 31 May 2020EOSSO 493.9 km × 511.3 km97.4° 45625 Long March 2D Jiuquan SLCGaofen 9-03 17 June 2020EOSSO 491.5 km × 513.9 km97.4° 45794 Long March 2D Jiuquan SLCGaofen DUOMO 3 July 2020EOSSO 635.5 km × 657.6 km97.9° 45856 Long March 4B Taiyuan SLCGaofen 9-046 August 2020EOSSO497.9 km × 506.4 km94.4°46025Long March 2DJiuquan SLCGaofen 9-0523 August 2020EOSSO493.5 km × 511.9 km97.4°46232Long March 2DJiuquan SLCGaofen 11-027 September 2020EOSSO500.7 km × 505.2 km97.4°46396Long March 4BTaiyuan SLCGaofen 1311 October 202050m VIS, 400m MWIRGEO35,782.5 km × 35,806.1 km0.2°46610Long March 3BXichang SLCGaofen 146 December 2020EOSSO492.9 km × 198.4 km97.4°47231Long March 3B/G5Xichang SLCGaofen 12-0230 March 2021SARSSO634.7 km × 636.6 km97.9°48079Long March 4CJiuquan SLCGaofen 5-027 September 2021303km POL MSI, 0.3cm HSI, 30m HSISSO705.4 km × 710.2 km98.2°49122Long March 4CTaiyuan SLCGaofen 11-03 20 November 2021 EOSSO 498.6 km × 504.8 km97.4° 49492 Long March 4B Taiyuan SLCGaofen 3-0222 November 2021C-band SARSSO757.5 km × 759.2 km98.4°49495Long March 4CJiuquan SLCGaofen 3-03 6 April 2022C-band SARSSO 757.8 km × 758.9 km98.4° 52200 Long March 4C Jiuquan SLCGaofen 12-0327 June 2022SARSSO633.3 km × 367.1 km98.0°52912Long March 4CJiuquan SLCGaofen 5-01A 8 December 2022HSISSO706.1 km × 709.0 km98.1°54640 Long March 2DTaiyuan SLCGaofen 11-04 27 December 2022EOSSO 498.6 km × 504.8 km97.4°54818 Long March 4BTaiyuan SLCGaofen 13-0217 March 2023UnknownGTO35,788.4 km × 35,802.1 km3.0°55912 Long March 3B/EXichang SLCGaofen 12-0420 August 2023SARSSO626 km × 630 km97.9°57654Long March 4CJiuquan SLCGaofen 11-05 19 July 2024EOSSOLong March 4BTaiyuan SLCGaofen 12-0515 October 2024SARSSOLong March 4CJiuquan SLCTable data sourced from previously cited references, CelesTrak, N2YO, NASA, and the U.S. Space Force
See also
Yaogan Jilin-1 Shijian China Siwei Fengyun
References