The task as described on the official ESA Lunar Robotics Challenge website:

• Climb from a “landing site” to the rim of a lunar-like crater.
• Descend into the crater, negotiating an incline of about 40 degrees.
• Operate in sunlight on the crater’s rim, and in the dark interior of the crater.
• Reach the bottom of the 15 m deep crater.
• Locate and retrieve at least 100g of selected, visually distinctive, soil samples from the bottom of the crater.
• Return to the rim and the “landing site”.

The whole task is to be solved by a remotely operated mobile unit which is less than 100 kg in weight and less than 0.5 m³ in storage mode.

Operation concept

( click to enlarge )

Launching from the "landing site", the CESAR (Crater Exploration and SAmple Return) robot first has to climb the outer crater rim, which requires it to operate in directly enlighted areas.

After, it is to proceed into the interior of the crater, which requires the robot to descend on rough terrain in a possibly dark environment with a considerable downward slope of up to 40%.

In a third step, the vehicle has to be capable of collecting a sample volume of a half loose material such as particulated rock in a possibly completely dark environment and difficult terrain.

Not at least, the robot has to climb up the same difficult terrain as it descent on into the crater before and return the sample probe safely to the landing site, where it will be loaded into a transport vehicle and returned to earth.