First up, on September 7 at 03:01 UTC, a Chinese Long March 4C launched the Gaofen 5-02 satellite into a sun-synchronous orbit from the Taiyuan Satellite Launch Center in northeast China. Gaofen 5-02 is a replacement for the first Gaofen 5 satellite launched in 2018 under the China High Definition Earth Observation System, a constellation of Earth-observing satellites.

The first Gaofen 5 had six different instruments for measuring several different areas: atmospheric haze, air quality, climate change, and ozone measurement. These were the Advanced Hyperspectral Imager, the Visual and Infrared Multispectral Sensor, the Atmospheric Infrared Ultraspectral Sensor, the Greenhouse-gas Monitoring Instrument, the Environmental Monitoring Instrument, and the Directional Polarization Camera.

That’s a lot of sensors, but very simply, they are measuring different indicators related to air pollution and climate change. For example, there are sensors that measure ozone, atmospheric haze, and greenhouse gases including methane, nitrogen dioxide, and carbon dioxide.

One of the sensors called the Atmospheric Infrared Ultraspectral Sensor (AIUS) looks at the light from the Sun as it passes through the atmosphere where the Earth is occulting (or blocking) the Sun. As the satellite orbits the Earth, it can point the AIUS at the Sun and measure the light as it passes through different layers of the atmosphere. From this, it determines the temperature, pressure, and percentages of different gases such as water vapor, ozone, carbon dioxide, and nitrogen dioxide at different altitudes.

Gaofen 5-02 marked the 30th Chinese launch of the year.

More Information

CASC press release (Chinese)

PDF: Mission Overview GaoFen-5 (CEOS)

Gaofen 5 info page (Gunter’s Space Page)

Launch video