There are many reasons why Mars excels at destroying expensive equipment. For one thing, its entire surface is made of partially-magnetized dust. For another, Mars possesses just enough atmosphere so that the dust floats and coats photographic lenses. At the same time, it doesn’t have enough of an atmosphere to protect electronics from ultraviolet radiation. The trace gases and humidity in the air it does have contaminate all but the most tightly sealed instruments. Mars’ frigid temperatures, low pressures and rapidly changing winds push landers to their operational limits. To build equipment that functions well under these conditions, we need testing environments on Earth that duplicate Mars’ many imperfections as perfectly as possible.
In their article, "Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars," Jesus Sobrado and his colleagues at the Center for Astrobiology in Madrid explained how they created the world’s best testbed for Martian expedition equipment. While other chambers may integrate two or three of the factors that make life difficult on Mars, the Center for Astrobiology’s simulator offers almost all of the red planet’s challenging variables. These includes not only low pressures and temperatures, but also dust, wind, relative humidity, atmospheric gases and even radiation.