Mars Express will help answer questions concerning the creation and evolution of the Martian landscape by mapping the Martian sub-surface, surface, atmosphere and ionosphere from orbit.

The orbiter's payload, weighing about 116kg, consists of the following six instruments:

ASPERA

Energetic Neutral Atoms Analyser

ASPERA will study how the solar wind interacts with the Martian atmosphere, using a technique known as energetic neutral atom imaging, and thus throw light on the mechanisms by which water vapour and other gases could have escaped from Mars in the past.

HRSC

High / Super Resolution Stereo Colour Imager

The HSRC is a stereoscopic camera that will photgraph the Martian surface to reveal detail as small as 2m. The images will be used to produce a geological map showing the location of different minerals and rock types.

MaRS

Mars Radio Science Experiment

MaRS will use radio waves to study both the surface and atmosphere. It will measure local variations in gravity over the surface of Mars and will provide pressure and temperature profiles of the atmosphere.

MARSIS

Subsurface Sounding Radar / Altimeter

MARSIS will map the distribution of water and ice in the upper portions of the Martian crust to a depth of 3 to 5km, using techniques similar to oil prospecting on Earth. It will be able to distinguish between dry, frozen and wet soil.

OMEGA

IR Mineralogical Mapping Spectrometer

OMEGA will determine the mineral content of the Martian surface and the molecular composition of the atmosphere by analysing sunlight reflected from the surface and diffused through the atmosphere. OMEGA aims to contribute to our understanding of the structure of the Martian landscape and the role played by water over timescales ranging from seasons to billions of years.

PFS

Planetary Fourier Spectrometer

PFS will measure the global atmospheric distribution of water vapour and other minor constituents with greater accuracy than previous missions.

SPICAM

UV and IR Atmospheric Spectrometer

SPICAM will measure the composition of the Martian atmosphere over smaller volumes than the PFS instrument. It will use the technique of stellar occultation to measure the vertical profiles of CO2, temperature, ozone, aerosols and clouds.