The mosaic was created using data from Mars Express’s High Resolution Stereo Camera (HRSC).
HRSC normally photographs Mars’s surface from an altitude of about 300 km – the closest the spacecraft gets to Mars in its elliptical orbit – with the resulting images covering areas about 50 km across. However, the mosaic presented here uses a slightly different approach. To view the planet more widely, HRSC gathered 90 images at higher altitudes (of 4000 to 10 000 km), thus capturing areas of around 2500 km wide. These images were then put together to form a full global view.
Such large-scale images are typically obtained to observe weather patterns on Mars – but even in the absence of atmospheric phenomena they offer wonderful views of the planet’s surface.