Tianwen-1, China’s first Mars probe, lifted off on July 23, 2020 from the Wenchang Space Launch Center on Hainan, an island off China’s southeastern coast.

One of the payloads on the Mars orbiter, the high-resolution camera was developed by the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences to take fine observatory images of key areas on the surface of Mars. It also helps provide strong support for research into the planet’s topography, landforms, and geological structure.

On February 5 when Tianwen-1 has been in space for over half a year, the China National Space Administration published the first image of Mars captured by the high-resolution camera of Tianwen-1 at a distance of about 2.2 million kilometers from Mars. On March 4, the administration released panchromatic images taken by the high-resolution camera at a distance of 330 to 350 km above the surface of Mars, with a resolution of about 0.7 meters.

The first image of Mars taken by the high-resolution camera of the Tianwen-1 probe

A high-resolution image of Mars captured by the high-resolution camera of the Tianwen-1 probe

The high-resolution camera of the Tianwen-1 probe [IMAGE: CHANGCHUN INSTITUTE OF OPTICS, FINE MECHANICS AND PHYSICS, CHINESE ACADEMY OF SCIENCES]

The high-resolution camera of the Tianwen-1 probe adopts a long-focus off-axis three-mirror anastigmatic optical system, featuring strong light collection, full utilization of effective aperture, high optical transfer function, and strong stray light suppression. Its focal length is 4,640 mm, and the full field-of-view is 2 degrees horizontally and 0.7 degrees vertically.

The optical system adopts an advanced low-sensitivity design and uses off-axis higher-order aspheric mirrors with high gradient and large deviations to ensure aberration correction of the system and a large telephoto ratio.

In addition, the all-carbon optical-mechanical structure solves the contradiction between the camera’s long focal length technical indicators and lighter weight. The carbon fiber truss makes possible the high-precision position of optical components and the light weight structural design, bringing the total mass of the camera down to less than 43 kg.

The focal plane of the camera is equipped with three 5-band multispectral TDI CCD image sensors that are able to collect panchromatic, blue, green, red, and near infrared images as well as two domestic area array panchromatic CMOS image sensors, which allows both multispectral linear array push-broom imaging and full-range color array imaging. The camera has the ability to capture high-resolution panchromatic images, and to color blend images and video images of the surface of Mars.

Source: Changchun Institute of Optics,

Fine Mechanics and Physics,

Chinese Academy of Sciences