On July 29 at 04:01 UTC, a Chinese Long March 2D launched the Tianhui 1-04 satellite into a Sun-synchronous orbit from the Jiuquan Satellite Launch Center. Tianhui 1 is a military-operated constellation of stereoscopic mapping satellites capable of taking a three-dimensional image with a ground resolution of five meters. The satellite also contains a multispectral imaging infrared sensor. Both cameras take pictures with a swath width of 60 kilometers. The satellite’s mission was described as being mainly used for scientific experimental research, land use and resources monitoring and mapping, and other tasks.

Most people have stereoscopic vision, meaning that they can see in three dimensions, thanks to two eyes, and thus discern where things are located spatially. This is because their two eyes are slightly separated horizontally. Each eye sees a slightly different image, but the brain combines the two images allowing the brain to perceive three dimensions. This can be done with satellite imagery, too, either with two different satellites passing overhead a target in coordination or with one satellite with a pair of cameras. This kind of data is useful when you want to know if that nice green bike path through green fields happens to have a couple of killer hills in the middle. With normal imaging, that hill might just surprise you.

More Information

CASC press release (Chinese)

Tianhui info page (Gunter’s Space Page)

Launch video