Mars Express Credit - ESA

The European Space Agency's Mars Express orbiter, designed to be built more quickly than any other comparable planetary mission, was a resounding success. The Beagle 2 Mars lander was released from Mars Express on approach to the Red Planet, but did not return any data.

Prime contractor was Astrium, Toulouse, France, leading a consortium of 24 companies from 15 European countries and the United States. The Beagle lander was developed by the University of Leicester, UK. Launch mass of 1120 kg consisted of the 113 kg orbiter and 60 kg lander.

The Orbiter's instruments included:

• High Resolution Stereo Camera (HRSC), designed to image the entire surface of Mars at high resolution (10 meters/pixel) and selected areas at super resolution (2 meters/pixel)
• Energetic Neutral Atoms Analyzer (ASPERA), which ASPERA measured ions, electrons and energetic neutral atoms in the outer atmosphere, to reveal the numbers of oxygen and hydrogen atoms (the constituents of water) interacting with the solar wind and the regions of such interaction.
• Planetary Fourier Spectrometer (PFS), designed to determine the composition of the Martian atmosphere from the wavelengths of sunlight (in the range 1.2-45 microns) absorbed by molecules in the atmosphere and from the infrared radiation they emit. It measured the vertical pressure and temperature profile of carbon dioxide which made up 95% of the Martian atmosphere, and looked for minor constituents including water, carbon monoxide, methane and formaldehyde.
• Visible and Infra Red Mineralogical Mapping Spectrometer (OMEGA), designed to produce a map of the mineral composition of the surface at 100 meter resolution. It measured the visible and infrared light reflected from the planet's surface in the wavelength range 0.5-5.2 microns.
• Sub-Surface Sounding Radar Altimeter (MARSIS), designed to map the sub-surface structure to a depth of a few kilometers. The instrument's 40-metre long antenna sent low frequency radio waves towards the planet, which reflected from any surface they encounter.
• Mars Radio Science Experiment (MaRS), which used the radio signals that convey data and instructions between the spacecraft and Earth to probe the planet's ionosphere, atmosphere, surface and interior.
• Ultraviolet and Infrared Atmospheric Spectrometer (SPICAM), designed to determine the composition of the atmosphere from the wavelengths of light absorbed by the constituent gases. The ultraviolet (UV) sensor measured ozone, which absorbed 250-nanometre light, and the infrared (IR) sensor measured water vapor, which absorbed 1.38 micron light.

Spacecraft operations were conducted from the European Space Operations Centre (ESOC), Darmstadt, Germany, via the ESA ground station in New Norcia, near Perth, Australia. The spacecraft was designed for two Martian years of operation (3.7 earth years).

The Beagle 2 lander was planned to: