Exploring the red planet from orbit and on the ground

A panoramic view of the interior of Victoria Crater on Mars. This image was taken by the NASA rover Mars Opportunity in late September 2006. The opposite slopes of the crater are clearly visible along with a dune field at the bottom. Image: NASA/JPL-Caltech Scientists have used the NASA probe Mars Reconnaissance Orbiter to image the robotic rover Opportunity on the edge of Victoria Crater. The view means astronomers have the chance to directly compare ground- and space-based images to decide where the rover should go next.

An image of the Victoria Crater on Mars from the Mars Reconnaissance Orbiter spacecraft taken on 3 October 2006. The probe was almost 300 km above the 2.5 km diameter crater. As well as the slopes of the crater rim, a dune field of Martian dust can be seen in the centre. Image: NASA/JPL/UA Victoria Crater is about 2.5 km across and was chosen as a target because it contains many exposed layers of rocks, which are a record of geological (or areological – the Martian equivalent) history.

Opportunity landed in early 2004 and has spent more than two and a half years driving around the Martian surface under the control of Earth-based planetary scientists. In that time it has covered a distance of 9 km.

Images from Opportunity give a dramatic view of the interior of the crater, including a field of dust dunes at the bottom. The images from Mars Reconnaissance Orbiter show the same site and Opportunity can be seen at the ‘Duck Bay’ site, an alcove on the crater rim.

A portion of an image of Victoria Crater taken by the spacecraft Mars Reconnaissance Orbiter. The rover Opportunity can be seen along with the tracks that it made as it drove to its position on the crater rim. Image: NASA/JPL/UA Now NASA scientists have a hard decision to make. They may choose to drive Opportunity into Victoria Crater to take a closer look at the layers of rock it contains. This is a risky manoeuvre. If the slopes of the crater are made of loose material the rover may struggle to drive out again. But even if this happens, Opportunity and Spirit (the twin rover in Gusev Crater on the other side of the planet) have performed far beyond expectations – their original lifespan was expected to be just 100 Earth days.