By David Shukman
BBC Science Correspondent, in Tenerife
The landscape is harsh, the air dry and the altitude challenging.
That's not how most people think of the holiday island of Tenerife, but for space scientists and engineers, the barren terrain here makes the ideal training ground for Europe's latest mission to the Red Planet.
Amid the rocks and dust of the slopes of the volcano El Teide, a team from the aerospace company EADS-Astrium has spent the past week testing a concept rover.
The engineers hope their work will be incorporated into a robot vehicle called ExoMars which the European Space Agency will launch to the Red Planet in 2011.
Roughly the size of a go-kart, the Astrium chassis is a gleaming six-wheeled device that embodies Europe's best hope so far of making a landing on Mars, and of unearthing evidence to answer the generations-old question, "was or is there life up there?"
Under a razor-sharp sky, I watched as the lightweight aluminium wheels scratched and pulled their way over lumps of lava - if one sticks, the other five take up the strain.
Off-road and off-planet
Top speed is only one-tenth of a mile per hour, but the aim is durability and the test runs so far show that broadly this machine is capable of operating not just off-road but also off-planet.
Not surprisingly there were hitches - nothing major but enough to grind the rover to a halt.
Sometimes the laptop that acts as the brain for the time being played up, sending error messages rather than commands to the electric motors. At one point, the batteries - borrowed from a golf buggy - ran low.
And at least once, the controller - the kind of thing usually seen in the hands of a teenage gamer - seemed to have no control at all.
The Sun was relentless and the wind was chilling, but the head of the rover project, Lester Waugh, never lost his temper.
With a toolbox in one hand and a penknife and sticky tape in the other, he and a colleague patched up the problems and kept the show on the road.
"I'm very enthused about this," he said. "We've come a very long way in the past 12 months. There's still a lot to do but we've got time."
These trials were designed to test the locomotive aspects of the rover - to assess how steep a slope it can tackle and how it copes with sand, gravel and rock.
Memories of Beagle 2
The final ExoMars rover will integrate a semi-autonomous navigation system and science packages - the instruments that would scan, drill and sample the Martian surface to hunt for signs of life.
If there's one cloud on the immaculate blue sky here, it's the memory of the ill-fated Beagle 2 mission, which crashed on Mars on Christmas Day 2003, the first and last British attempt to visit another planet.
The rover will carry a suite of scientific instruments
That craft was built by the same team now working on the concept rover. This time, says Lester Waugh, "we've got bigger margins, with more finance and more support. We're really confident".
Still, the risks are huge. Europe has a vision of landing humans on Mars in 30 years' time and this next mission is a key stepping stone.
For their scientists and engineers at Astrium, based in the Hertfordshire town of Stevenage, there's one phrase they don't want to hear: "Stevenage we have a problem."