MARS EXPRESS - A challenge for European industry

Mars Express, the first European spacecraft to visit the planet Mars, was launched on 2nd June 2003 by a Starsem Soyuz rocket from the Baikonur Cosmodrome. Mars Express was built under EADS Astrium’s prime contractorship with the involvement of over 40 European companies. Starsem, a subsidiary of EADS (35%) and Arianespace (15%) is responsible for the marketing of the Soyuz rocket.

Mars Express will be the cheapest ever mission to Mars. The contract between ESA and Astrium was signed in March 1999. The cost of the satellite including in-flight operations support up to final commissioning in March 2004, is €84 million. 3 to 4 times cheaper than previous scientific missions to Mars.

The spacecraft, which will enable scientists to detect subterranean water on Mars, benefited from an exceptionally favourable launch window on 2nd June 2003 with Earth and Mars approaching their closest point, about 55 million kilometres, which only occurs every 17 years.

The Mars Express spacecraft must have a high level of autonomy as the distance from the Earth will be up to 2.5 times the distance between the Earth and the Sun and the one-way transmission time for communications signals can be up to 20 minutes. The spacecraft has to remain fully operational even during “opposition” and “conjunction” phases with the Sun, when, behind by the sun, there can be up to one month without any command, control or telemetry. In the case of on-board anomalies, the spacecraft must be able to detect the failure, isolate it and continue the mission.

Seven scientific instruments on board will perform numerous tasks: global high-resolution photogeology, global mineralogical mapping, global atmospheric circulation and mapping of the atmospheric composition, radar sounding of the subsurface structure down to the permafrost, study of surface-atmosphere interactions and interaction of the atmosphere with the interplanetary environment.

The orbiting spacecraft will circle the Red Planet for at least one Mars year, that is 687 terrestrial days whilst Beagle 2 has a nominal lifetime of 180 sols or about 6 months. Thereafter the orbiter mission will possibly be lengthened by a further Mars year. In this second phase the orbiter will function primarily as a relay station to transfer the data of other scientific Mars missions to Earth.

EADS Astrium is the Prime Contractor for both the Mars Express spacecraft and the Beagle 2 probe and is the supplier for the High Resolution Stereo Camera, one of the 7 scientific instruments.

EADS Astrium, as a multinational company, is moreover involved in the design and development of the software, in France, the propulsion system, in the UK, and the electrical system and the manufacturing of the Solar Arrays, in Germany. The company is responsible for the technical interface with the launcher and the industrial management of the scientific instruments developed by European and US laboratories. EADS Astrium also designed and manufactured the Beagle 2 lander, carried by the Mars Express spacecraft. Beagle 2 will be separated from the satellite on December 19th 2003 and will land on Mars on 25 December to collect and analyse soil and rock samples in situ.

EADS Space Transportation is the supplier of the Beagle 2 aeroshell and Starsem provided the launch services.

EADS Astrium is the leading satellites company in Europe. Its activities cover complete civil and military telecommunications and Earth Observation systems, Science and Navigation programmes, and all spacecraft avionics and equipment. EADS Astrium is wholly owned by EADS SPACE. In 2002 EADS SPACE had a turnover of €2.2 billion and 12,300 employees in France, Germany, the United Kingdom and Spain.

Technical Data Mars Express

The engine on Mars Express, located on the underside of the spacecraft will be used principally when the spacecraft reaches Mars, to decelerate it and steer it into its operational orbit. Course corrections can be achieved using the eight small manoeuvring thrusters, each of which produces a thrust of ten Newtons.

Two solar panels, which unfolded shortly after separation from the launcher, provide the spacecraft with electrical power. The solar arrays have an area of 11 m2 and produce an output of 650 watts. During the phases when the orbiter is eclipsed by Mars, the spacecraft will rely on power from three newly-developed lithium-ion batteries, which can later be recharged from the solar arrays.

Dimensions: 1.5 x 1.8 x 1.4 m Launch Mass(total): 1200 kg which includes Beagle 2: 74kg Propellant: 480 kg Payload 116 kg

Propulsion: Main engine Thrust: 400 N 8 Manoeuvring Thrusters: 10 N each

Power Supply: Solar Panels, Area 11.4 m3, Power 660 W, 3 Lithium-Ion Batteries: 22.5 Ah each.

Communication: Two-way communication in S and X-band Daily data transfer rate: 500 to 4300 Mbits

Launcher: Soyuz/Fregat