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About TanSat

TanSat. Copyright: MOST, CAS, CMA.

The TanSat mission is one of the Earth Observation projects managed by the Ministry of Science and Technology of China. The principal goal of this project is to detect and monitor carbon dioxide (CO2) in the atmosphere.

The primary research goal of the TanSat mission is to monitor the variation of CO2 on a seasonal scale, but the mission is also improving knowledge of the distribution of CO2 on a global scale, understanding how it contributes to climate change.

The satellite hosts two instruments:

  • ACGS (Atmospheric Carbon-dioxide Grating Spectrometer), dedicated to measurements of the near-infrared absorption by CO2
  • CAPI (Cloud Aerosol Polarization Imager), devoted to studying cloud and aerosols in high-resolution. Data from the instrument can be used to compensate for errors in the measurement of CO2.
TanSat mission details
Date of launch03:22 on 22 December 2016 (GMT+8)
Mission StatusOperational (extended)
Orbit Height700 km
Orbit TypeSun-synchronous
Orbit Period90 minutes
Orbit Repeat Cycle16 days
Onboard sensors provided under TPMCAPI, ACGS

TanSat Objectives

The main objective of the TanSat mission is to retrieve and monitor the atmosphere column-averaged CO2 dry air mole fraction (XCO2) with precisions of 1% (4 ppm) on national and global scales.

TanSat Instruments

The TanSat satellite carries two instruments: ACGS (Atmospheric Carbon-dioxide Grating Spectrometer), and CAPI (Cloud Aerosol Polarization Imager), both dedicated to global CO2 detection and monitoring.

The instruments can observe in three acquisition modes, with the same data sampling rate: nadir, ocean glint and surface target.

Atmospheric Carbon-dioxide Grating Spectrometer (ACGS)
Number of Channels2000
Observation ModeNadir, glint, target
Swath20 km
Spatial Resolution3 km along track, 2 km cross track
Bands (spectral range)758-776 nm, 1594-1624 nm, 2041-2081 nm


Cloud Aerosol Polarization Imager (CAPI)
Number of Channels5
Observation ModeNadir, glint, target
Swath375 km
Bands (central wavelength)380 nm, 670 nm, 870 nm, 1375 nm, 1640 nm
Spatial Resolution250 m (at 380, 670, 870 nm), 1000 m (at 1375, 1640 nm)
Polarization angles0°, 60°, 120°, at 670 nm and 1640 nm

The TanSat mission also performs a regular calibration, in four different modes: dark current, lamp, solar viewing for spectral and radiometric calibration; moreover, for the radiometric calibration, CAPI instrument uses lunar viewing.



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