Here's a babelfish translation of a french report about Mars Express discovering light in the Martian night.

PARIS (AFP) - light in the Martian night, due to the presence of nitric oxide molecules, has been just detected by one of the instruments of the European probe March-Express train, in orbit for one year around "red planet", announced to Friday in the Science review an international team of researchers. The cartography of this light output, underlines the person in charge for the team, Bertaux Jean-Wolf, of the National Scientific Research Center (CNRS - France) is of importance in particular from the point of view of future Martian missions: by refining the comprehension of the circulation of the atmosphere and the climate of Mars, it makes it possible to consider, for the loads which will be sent to the surface of Mars, the use of the atmospheric technique of braking (or aérocapture), therefore missions at lower costs. It is known for a long time that the Earth's atmosphere spontaneously emits light in the night sky, but never up to now no light had been detected in the night of Mars, if it is not weak "clearly of Phobos" (one of the satellites of Mars), Martian equivalent of our moonlight. The phenomenon recorded by the ultraviolet spectrometer and infra-red SPICAM, explains Jean-Wolf Bertaux, its person in charge, is the same one as that which had been observed and explained twenty-six years ago on Venus: side day of planet, the ultraviolet solar radiation dissociates the carbon dioxide molecules (CO2), principal constituting atmosphere of Mars, and the nitrogen molecules (N2). Each nitrogen atom combines then with an oxygen atom to form the nitric oxide molecule (or nitric oxyde, NO). In the upper atmosphere of planet (with more than 120 kilometers of altitude), there is, on the side day, a production continuous, but weak, nitrogen and oxygen atoms. During their slow descent in the atmosphere, when their concentration increases, these atoms end up recombining and thus forming, around 70 km of altitude, the light observed by SPICAM. This emission, noted the researchers, is intense in the area of the South Pole of Mars. It was then the full winter for this pole (thus the permanent frozen night), season during which 30% of all the atmosphere of Mars condense on the ground, to form a cap of one meter thickness dry ice. This area, advance Bertaux Jean-Wolf and its colleagues, would act as vacuum cleaner, the air frozen on the ground having to be replaced by horizontal winds but also by a vertical descent. "It is this vertical descent, which also exists on Earth, in the night of the polar winter, that the light output observed would trace." Currently, the models of general circulation of the atmosphere, such those which use the weather services to predict time on Earth, also exist for the planet Mars, but, by quasi total lack of measurements, they are still dubious for the upper atmosphere, there where the orbital operations of the future machines Martians could take place. Thanks to measurements of SPICAM, such "economic" operations more, thanks to the technique of atmospheric braking, can be considered.