Issue 84

China Launches Two Tianhui-5 Remote Sensing Satellites

31 Oct 2023: China launched a modified LM-6A from Taiyuan Satellite Launch Center carrying the Tianhui-5A and 5B remote sensing satellites. According to official sources, the satellites entered their intended orbits and “will be used for geographic mapping, land resource survey, scientific experiments and other…

31 Oct 2023: China launched a modified LM-6A from Taiyuan Satellite Launch Center carrying the Tianhui-5A and 5B remote sensing satellites. According to official sources, the satellites entered their intended orbits and “will be used for geographic mapping, land resource survey, scientific experiments and other missions,” Launch Video.

Tianhui translates to “sky-drawing” and is a series of unclassified cartography satellites operated by the China Aerospace Science and Technology Corporation (CAST).

-The Long March 6A has taller payload fairings, ~2 m taller than LM-6 Y1/2. This is the first time the LM-6A has been used to launch Tianhui satellites.

-The two Tianhui-5 mapping satellites are in a 606 x 607 km x 97.8° Sun-sync orbit.

-Tianhui-5A/B’s altitude is greater than all other Tianhui satellites with the exception of Tianhui-6A/B (launched in March 2023). Tianhui-6A/B are in an 888 × 880 km orbit with an inclination of 99°.

– Tianhui-5A/B orbit is similar to that of the Tianhui 6A & 6B pair, all four satellites will probably work together to produce 3D radar imaging

– The Tianhui constellation consists of 14 satellites. China has launched 11 since 2019.

– The four Tianhui-1 spacecraft operate independently, and are equipped with three separate Earth observation cameras: a panchromatic camera (5m), a panchromatic CCD camera (2m) and a multi-spectral imager (10m).

Tianhui-2 satellites were China’s first microwave surveying satellite system based on synthetic aperture radar (SAR) technology. TH-2 satellites operate in the X-band, with a 3 m resolution. In May 2023, China maneuvered Tianhui 2-02A & 02B to within 1 km of one another.

– Tianhui 2-02A moved into proximity with 2-02B, after making multiple altitude changes, whereas the SMA for 2-02B remained unchanged.

– Tianhui-4A/B, 6A/B – and now 5A/B satellites (Tianhui-3 does not exist yet) – operate in formations of two, and are also likely SAR capable.

– Known Yaogan SAR satellites operate with apogees between 484 – 694 km, and Gaofen SAR satellites range 626 – 749 km. Commercial SAR imager Capella operates satellites between 399 – 491 km.

Long March 6A and Long March 6 launch vehicles

Tianhui-5 satellite animation

Tianhui-5 mission patch

Tianhui-6A/B and Tianhui-5A/B