Astrium to fly with BepiColombo

Astrium is set to build the Mercury probe BepiColombo on behalf of the European Space Agency (ESA) following the signing of a contract worth €350.9m.

BepiColombo is scheduled to leave Earth in 2013 and is considered to be the most sophisticated scientific mission in the history of European space exploration to date.

BepiColombo will consist of three modules: a European orbiter, a Japanese orbiter and a transfer module carrying the two spacecraft to Mercury. The complete unit will have a height of approximately 5m and a mass of about three tonnes, of which about 50% is propellant.

The European ‘Mercury Planetary Orbiter’ (MPO) will be equipped with eleven scientific instruments. Flying in a polar orbit, it will study Mercury for at least a year, imaging the planet’s surface, generating height profiles, and collecting data on Mercury’s composition and atmosphere. The Japanese ‘Mercury Magnetospheric Orbiter’ (MMO) will investigate the planet’s magnetic field with its five on-board instruments.

Astrium in Germany leads an industrial team whose core members include Astrium Ltd in the UK and Thales Alenia Space in Italy. Astrium in Friedrichshafen is responsible for the entire three-section spacecraft, Including attitude and orbit control design and development. The integration of the engineering model of BepiColombo will take place in Friedrichshafen.

Astrium in the UK is responsible for the structure of the entire spacecraft including the launch vehicle adapter, the complex mission analysis that will require numerous swing-bys of the Earth, the moon, and Venus in its six-year flight plan, and also the two chemical propulsion systems and the ion propulsion system.

Astrium in France will develop the on-board software, building on experience gained from the Rosetta, Mars Express and Venus Express probes that are already in space.

Challenges

One of the greatest challenges facing Astrium engineers is that of preparing BepiColombo for the extreme temperatures it will encounter. Close to Mercury, solar radiation is up to ten times stronger than on Earth, with temperatures of up to 470^oC on the planet’s surface.

Experts at Astrium will use a variety of techniques to protect the electronics and scientific instruments from the extreme heat including a newly designed insulating blanket made of a combination of glass fibre, titanium film and ceramic fibres, and a radiator to release the heat from the probe’s interior into space.

The combination of a conventional chemical propulsion system with an ion propulsion system will provide the required thrust on BepiColombo’s journey. Several swing-by manoeuvres are planned in order to propel the probe out of Earth’s orbit and into its planned trajectory. During these manoeuvres, BepiColombo will be accelerated using the gravity fields of the Moon, then decelerated by Earth and Venus. After two further swing-by manoeuvres at Mercury, BepiColombo will reach its destination in 2019 and enter into a polar orbit.

Scheduled to explore Mercury for at least 12 months, the spacecraft’s mission may be extended by a further year.