Posted 18 October 2018 in Blog, Space.
BepiColombo will allow scientists to develop a better understanding of the formation and evolution of the solar system. The mission is scheduled to launch aboard an Ariane 5 from Europe’s Spaceport in Kourou, French Guiana, on October 20, 2018.

BepiColombo is the first European mission to Mercury, the smallest and least explored planet in the inner solar system. The mission will build on the legacy of NASA’s Messenger, which orbited the planet between 2011 and 2015 and seems to have raised more questions than answers.

Due to its small size, scientists believed Mercury’s iron core would have cooled and solidified, in contrast to the Earth’s. However, measurements by Messenger revealed that the planet has a magnetic field, which indicates a liquid interior. BepiColombo will make measurements designed to reveal the planet’s internal structure in greater detail.

The spacecraft will also monitor the planet’s polar regions to investigate the presence of water ice in Mercury’s permanently shadowed craters. Measuring the exact chemical composition of the ice could help find out its origins. One of the theories that the spacecraft will try to solve is whether the ice derives from comets impacting the planet’s surface.

An ESA diagram to show the scientific themes explored using BepiColombo

A joint ESA-JAXA mission to Mercury

To cope with the extreme temperatures, BepiColombo counts on antennas, solar arrays, sun sensors, and multilayer insulation and has temperature-resistant outer layers and protective coatings. All of them have undergone significant testing at the European Space Research and Technology Centre to prove that they can withstand the violent shaking occurring during launch, the harsh radiation environment of space, and the high temperatures that will be encountered close to the Sun once orbiting Mercury. About 70 per cent of the technology needed for the mission had to be developed from scratch. To tackle such challenges, the European Space Agency (ESA) teamed up with the Japan Aerospace Exploration Agency (JAXA).

The mission consists of two scientific orbiters: ESA’S Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO). The European orbiter is carrying 11 specially designed instruments, and the Japanese counterpart has five; all of them are set to explore Mercury’s crater-pocked surface, enigmatic magnetism, and tenuous, vestigial atmosphere.

An ESA diagram to show the timeline of events as BepiColomo approaches Mercury

A 7-year journey

A big challenge for the mission is the Sun’s enormous gravity, which makes it difficult to place a spacecraft into a stable orbit around Mercury – even more, energy is needed than sending a mission to Pluto.

After launch, BepiColombo has to constantly brake against the gravitational pull of the Sun. Once launched, the spacecraft will have a 7.2-year cruise. The length of the journey is not because Mercury is so far away but because the spacecraft needs to be going slowly enough to enter a stable orbit. This is a particular problem for Mercury, with its extremely thin atmosphere.

To be able to tackle this, BepiColombo will perform a cleverly choreographed series of fly-bys—one by Earth, two by Venus and six by Mercury—designed to slow it down.

Watch BepiColombo launch live

Watch the launch live on October 20 from 03:15 CEST through the ESA web broadcast.