While approaching Mars on 19 December 2003, Beagle 2 was released and started its 6-day journey to the planet’s surface. However, the attempts to communicate with it on 25 December 2003, the date of its expected touchdown, were not successful. The Beagle 2 mission was declared lost on 6 February 2004. In contrast, the Mars Express orbiter started science observations as planned in January 2004, and since then it has been delivering an incredible amount of scientific results.

The ‘Express’ part of the name highlights the fact that the spacecraft was built more quickly than any other comparable planetary mission. In fact, it took only five years from mission approval to launch.
 
Objectives
 
In addition to global studies of the surface, subsurface and atmosphere of Mars with unprecedented spatial and spectral resolution, the unifying theme of the Mars Express mission from orbit is the search for water in its various states, everywhere on the planet by all its seven instruments using different techniques.

Main achievements so far

• The High-Resolution Stereo Camera (HRSC) has shown breathtaking views of the planet from both hemispheres, indicating very young ages for both glacial and volcanic processes, from hundreds of thousands to a few million years old, respectively.
• • The Infrared Mineralogical Mapping Spectrometer (OMEGA) has provided unprecedented maps of water-ice and carbon dioxide-ice in the polar regions. It also determined that the presence of ‘phyllosilicate’ in some areas of the surface is a sign that abundant liquid water existed in the early history of Mars, while the presence of sulphates and iron oxides suggests a colder drier planet at later stages, with only episodic water on the surface.
• The subsurface sounding radar (MARSIS) identified the presence of water-ice deposits underground and revealed the fine layering of polar deposits. The radar has also been probing the upper atmospheric layer (the ionosphere) and shown interesting structures associated with localised magnetic fields in the Martian crust, which originate near the surface of Mars.
• The Planetary Fourier Spectrometer (PFS) has made the most complete map to date of the chemical composition of the atmosphere, indicating the presence of methane. If confirmed, this could indicate volcanic process that are still active today or even active biochemical processes. PFS also produced temperature maps from the surface up to an altitude of about 50 km.
• The Ultraviolet and Infrared Atmospheric Spectrometer (SPICAM) has provided the first complete vertical distribution of carbon dioxide in the atmosphere, discovered the existence of a nightglow as well as auroras at mid-latitudes, produced the first ozone map, and reported the detection of the highest clouds ever observed at Mars.
• The Energetic Atoms Analyser (ASPERA) has identified solar wind scavenging of the upper atmospheric layers as one of the main culprits of atmospheric degassing and ‘escape’. By introducing a novel measurement technique for energetic neutral atoms , this experiment is also exploring a new dimension in the solar wind interaction with planets that do not have a global magnetic field.
• The Radio Science Experiment (MaRS) has studied the surface roughness, indirectly probed the Martian interior by detecting gravity anomalies affecting the spacecraft orbit, and discovered a previously unknown variable ionospheric layer due to meteors entering and burning up in the atmosphere.

Launcher

A Soyuz rocket with a Fregat upper stage, provided by Starsem, the European/Russian launcher consortium.
 
Journey
 
Mars Express left Earth with a velocity of 10 800 km/hr and cruised through interplanetary space for six months before reaching Mars. Once at the Red Planet, it entered a large, elliptical ’capture’ orbit, from which it progressed into its operational orbit. The operational orbit is nearly polar, with an inclination of 86°.
 
Mission lifetime
 
The mission was originally planned for one Martian year (687 days). It has already been extended three times, and is now funded for operations until the end of 2014.

Spacecraft
 
Design

Mars Express is a honeycombed aluminium box, within which all the systems and the payload are fixed. Although this shell, known as the bus, was designed especially for the mission, off-the-shelf components were used wherever possible. Also, technology designed for Rosetta was reused. Both approaches have helped to keep the cost of building the spacecraft down.

Mass

1200 kg in total (including 113 kg of payload, 65 kg of lander, and about 430 kg of propellants).

Dimensions

1.5 by 1.8 by 1.4 m (excluding solar panels). With solar panels extended, Mars Express measures about 12 m across.

Industrial involvement

The prime contractor was Astrium, Toulouse (France), leading a consortium of 24 companies from ESA’s 15 Member States and the United States. Throughout Europe, about 1000 engineers and scientists were directly involved in the development of Mars Express.

What's on board?
 
High Resolution Stereo Camera - HRSC HRSC is mapping the surface of the planet in 3D, colour and with a resolution of about 10 m.

Principal Investigator: G. Neukum, Freie Universität, Berlin, Germany.

Energetic Neutral Atoms Analyser - ASPERA ASPERA measures the way particles in Mars’s tenuous atmosphere interact with the solar wind (energetic particles given off by the Sun). The data allow scientists to estimate how dense the Martian atmosphere was in the past.

Principal Investigator: R. Lundin, Swedish Institute of Space Physics, Kiruna, Sweden.

Planetary Fourier Spectrometer - PFS PFS measures the composition and temperature of the planet’s atmosphere and the way it varies with altitude.

Principal Investigator: V. Formisano, IFSI-CNR, Rome, Italy.

Visible and Infrared Mineralogical Mapping Spectrometer - OMEGA OMEGA is mapping the mineral composition of the surface of Mars.

Principal Investigator: J-P Bibring, Institut d'Astrophysique Spatiale, Orsay, France.

Subsurface Sounding Radar Altimeter - MARSIS Altimeter MARSIS is a 40 m-long antenna that uses high-frequency radio waves to study the subsurface of Mars down to a depth of a few kilometres. In addition, the radar probes the ionosphere.

Principal Investigator: G. Picardi, Università di Roma 'La Sapienza', Italy.

Radio Science Experiment - MaRS Experiment MaRS is monitoring the distortion of radio communications from Earth owing to the ionosphere and atmosphere of Mars. It also provides insights into the gravitational field of Mars, the surface roughness and the solar corona.

Principal Investigator: M. Pätzold, Institut für Geophysik und Meteorologie, Universität zu Koeln, Germany.

Ultraviolet and Infrared Atmospheric Spectrometer - SPICAM SPICAM is investigating the composition of the atmosphere. It focuses on the ozone and water vapour cycle.

Principal Investigator: J-L Bertaux, Service d'Aeronomie du CNRS, Verrières-le-Buisson, France.

Operations
 
Mission control is located at ESA’s European Space Operations Centre (ESOC), Darmstadt, Germany. Communications with the spacecraft take place via the 35 m-diameter dish at New Norcia, near Perth, Australia. Mars Express is delivering information from its science instruments and ’housekeeping’ data.

ESA Mission Manager: Fred Jansen
ESA Project Scientist: Agustin Chicarro
ESA Project Manager: Olivier Witasse



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