Illustration: NASA/WIkipedia

ESA launches spacecraft on 9 billion kilometre journey into space

Wednesday 24 Oct 18


Kristian Pedersen
DTU Space
+45 20 11 74 77

Smallest planet in the solar system

Mercury is the smallest planet in our solar system and one closest to the Sun.

It consists of a barren and wasted stony desert with lots of craters with temperatures varying between 450°C during the day and -170 °C at night. As Mercury has no atmosphere, all heat flows into space at night.

Mercury’s radius at its equator is 2,440 kilometres compared to Earth’s 6,378 kilometres. The distance to the Sun is 0.387 compared to the Earth’s distance (Earth = 1). The distance to Earth alternates between 77 and 222 million kilometres.
DTU Space was at the launch, when ESA’s unique mission to Mercury was sent into space on Saturday morning on a journey to map the planet.

Shortly after 3.45 a.m on Saturday morning, an unmanned craft from the European Space Agency, ESA embarked on an epic journey. The craft BepiColombo will over the next seven years cover nine billion kilometres in order to reach mercury—the smallest planet in our solar system and the one closest to the Sun.

“There were applauses and cheers as BepiColombo launched successfully. We at DTU are not directly involved, but it is an exciting mission that will conduct the most comprehensive studies of Mercury so far,” says Director of DTU Space, Professor Kristian Pedersen.

The craft is now in on one of the most complex space flights ever carried out by ESA from the mission control centre ESOC in the German city of Darmstadt.

Danish equipment onboard
BepiColombo is an international collaboration led by ESA and the Japanese space agency JAXA.

DTU Space has been involved in the preliminary studies for the mission, among other things concerning a proposal for a magnetometer system.

The Danish company Terma has developed the power supply for the missions’ transport module.

First European mission
BepiColombo is the first European mission to Mercury, which is one of the least explored planets in the solar system.

The mission consists of two crafts, which will circle around the planet and conduct measurements in order to map the planet’ composition, magnetic field, atmosphere, dynamic features, and history, among other things. And it will shed light on how planets are generally formed close to their ‘mother stars’, which will add to our understanding of the universe and the formation of our solar system.

"Now we just hope that BepiColombo will get through its long journey out there safely."
Professor Kritian Pedersen, DTU Space

On its way out there, the craft will take several trips around other planets to use their gravitational powers to move into position for its trip around Earth, past Venus twice, and six times around Mercury. 

Sun challenging the mission
The Sun’s enormous gravitational force is another challenge which must be taken into account. This force pulls the craft, making it difficult to keep it in a stable orbit around Mercury.

And then there is the heat from the Sun. Mercury’s surface temperatures vary from about minus 170°C to over 400°C. The equipment on BepiColombo is therefore protected behind a heat shield that can tolerate 500°C.

But this will only be relevant in a few years, when the majority of the nine billion kilometres is close to being accomplished.

“Now we just hope that BepiColombo will get through its long journey out there safely,” says Kristian Pedersen.

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