ESA’s Sample Acquisition Field Experiment with a Rover (SAFER) has completed six “Martian days” of tests roaming Chile’s Atacama Desert. Nicknamed "Bridget," the prototype of the space agency’s ExoMars rover is part of a program to gain experience in building and operating planetary rovers in anticipation of the 2018 ESA Mars mission.
Bridget was built by Astrium in Stevenage, UK, and designed using ExoMars as a reference mission. It was equipped with three prototype instruments for exploring the Atacama, which is the driest, most lifeless spot on Earth, and an analog for the harsh Martian environment.
The instrument package consisted of a panoramic camera, a close-up imager, and a ground-penetrating radar. The final ExoMars rover will also include a robotic drill for collecting soil samples, which Bridget lacks, so this was simulated by a support team falling back on a pick and shovel. This was done not only to collect soil samples for Bridget to study, but also to corroborate the findings of the ground radar.
Though a ground crew was on hand, the test itself was controlled from the Remote Control Centre (RCC) at the Satellite Applications Catapult facility in Harwell, UK, where scientists and engineers followed the rover using a large video wall that displayed data from the rover mixed with 3D maps that were made using a UAV to simulate images taken from an orbiter. The idea was to create conditions where the RCC has to rely on data similar to what would come back from a real Mars mission. This was taken to the point of the ground crew using a broom to remove their footprints, so they couldn't be used as navigational clues by mission control.
"SAFER’s purpose is really to build up experience in rover field testing, so the remote team worked as realistically as possible," says Michel van Winnendael, who oversaw the test for ESA. "They had to plan good observation points for the instruments and safe paths for navigation. Once a plan was prepared it was dispatched to the local team in the field who then forwarded it to the rover, while trying to remain as ‘invisible’ as possible for the remote operators."
According to ESA, using the Atacama provided a strong element of realism as the rover had to contend with high winds, dust devils, and projecting rocks. In addition, the local geology proved similar to what the team expect to find on the Red Planet. "At our second simulated drill location the field team found a layer of rock starting at a depth of 60 cm," says Sev Gunes-Lasnet, project manager for RAL Space. "This comes close to the kind of features the team was looking for: analogues for locations on Mars which could hold traces of past or present life."
The video below shows the 3D representation of the test area as seen from the RCC.