BepiColombo –the Mission to Mercury

by Jamie Bradshaw

Scheduled to launch on October 19th, 2018, BepiColombo will become the third ever space probe to reach Mercury, the second to ever orbit Mercury, and the first mission to the planet that is not a NASA program.




BepiColombo is an ESA-JAXA joint mission to explore the planet Mercury, which is the least explored inner planet. It is named after Giuseppe “Bepi” Colombo (1920-1984), a scientist and mathematician at the University of Padua in Italy. He was the first scientist to come up with the interplanetary gravity assist manoeuvre, which was used in the 1974 Mariner 10 mission, the first probe ever sent to Mercury.

Artist's depiction of the BepiColombo mission, with the Mercury Planetary Orbiter (left) and Mercury Magnetospheric Orbiter (right (Wiki Commons)
The mission will send two probes to orbit Mercury for observations, called the MIO and the MPO. After launch, the probes will take 7 years to reach their destination, using ion thrusters and gravity assists. The probes will leave Earth in a hyperbolic orbit, and enter a solar orbit similar to that of Earths. After one and a half orbits, the probe and Earths orbits will intersect, allowing for a gravity assist and redirection towards Venus. The probe then has 2 flybys of Venus during its solar orbit, which adjusts the orbit enough for a Mercury flyby. After four flybys, the probe will be in a similar orbit to Mercury, at which point the probe will reduce its velocity with respect to Mercury over the course of the next 2 flybys, and then enter a polar orbit using chemical thrusters. Orbital height will then be decreased to observation height.

The MIO will be observing the magnetic fields and magnetosphere surrounding Mercury, and gathering data on the fields for further analysis on Earth. As magnetics are a speciality of the Japanese scientific community, JAXA, the Japanese space agency, have developed the MIO and will be responsible for controlling its operation once it reaches Mercury. The MPO, developed and controlled by the European Space Agency, will be attempting to determine the surface and internal chemical makeup of the planet. The large liquid iron core will be characterised, complete with gravitational and magnetic field mappings. In addition, the mission will attempt to check if there is ice in the polar regions of the planet, as some craters there are permanently in shadow, with no sunlight at all. Total surface mapping will be made possible by the polar orbit, as spacecraft in polar orbits, given time, pass over every part of a planet   ESA will also be providing the launch vehicle and be responsible for the orbital transfer between Earth, and the orbital insertion.




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