At a cost of ECU 150 m Mars Express is already the cheapest space mission ever proposed for the red planet. However, scientists on the committee are worried that if costs on Mars Express escalate, then other missions - such as PLANCK, a cosmology mission, and FIRST, an infrared telescope - will be threatened. The orbiter will carry seven scientific instrument including a high-resolution camera, a range of spectrometers, and a radar to penetrate below the surface. "Mars Express will confirm Europe's interest in a major target for space research in the new century, " said Roger Bonnet, ESA's director of science.

The orbital instruments are included in the cost of the mission. The committee also approved Beagle 2, a project led by the Open University in the UK, as the only appropriate lander proposal for Mars Express. However, the Beagle 2 team will have to raise £25 m (ECU 35.05 m) for the project, otherwise it will not be allowed on the mission.