The capability to orient Mars Express makes it possible to implement a great diversity of observations modes, in particular nadir and limb (fig 1). During day and night limb’s observations, 4 out of 7 MEX instruments (the spectrometers: SPICAM[1], OMEGA [2], PFS [3] and the high-resolution camera HRSC [4]) work together to provide spectra (.12 μm to 45 μm) of the Martian atmosphere (dust and clouds detached layers, day and night emissions), at each altitude step, with the associated image. Until now, the data reduction of observations of the limb from each Mars Express instrument had been done separately. Examples of the potential of each data set are given in Figures 2,3,4,5). We present here a database which makes it possible to retrieve...