BepiColombo: the extraordinary thermal protection of the probe that will study Mercury


In the night between Friday and Saturday, Arianespace launched BepiColombo on the planet Mercury that will reach after seven years of space travel. Because of the proximity of the planet to the Sun, the probe will evolve into a very hot environment that had to be taken into consideration at the time of its conception. The thermal protection of the satellite, a real challenge of the mission, was carried out by Thales Alenia Space. Paolo Musi, the head of scientific programs, explains how the probe will be protected from radiation and the heat of the sun.

Not surprisingly, this architecture, built around a main cryogenic stage, combines simplicity and robustness with a limited number of propulsive elements, while offering … "data-image =" https: //fr.cdn.v5 .futura- / buildsv6 / images / midioriginal / 4/8/5 / 485c816643_50034508_ariane-5-image.jpg "data-url =" / sciences / definitions / univers-ariane-5-3455 / "data-more =" More information ">Ariane 5 successfully launched the BepiColombo probe to chemistry: mercury, a chemical element
Mercury is the neighboring element of gold in the periodic table of elements and a favorite of alchemists. It has the distinction of being the only metal … "data-image =" jpg "data-url =" / sciences / definitions / astronomy-mercury-3722 / "data-more =" Read more ">mercury. The satellite, with a launch mass of 4,081 kg, was injected into an orbit in astronomy
In astronomy, the orbit designates the closed trajectory followed by a celestial body around another celestial body periodically, under the influence of … "data-image =" https: //fr.cdn.v5 / buildsv6 / images / midioriginal / 9/2 / e / 92eefd02ac_49145_iss-earth-sun-nasa-s-marshall-space-flight-center-flickr-cc-nc-20.jpg "data-url = "/ sciences / definitions / universe-orbit-873 /" data-more = "More information">orbit hyperbolic release, with as parameters a velocity having a direction and an intensity is represented by a vector, the velocity vector. Relative velocity is the velocity of one body relative to another or relative to a reference point. "Data-image =" 3/1/9 / 319daf63f4_77541_leibniz-dp.jpg "data-url =" / sciences / definitions / physics-speed-324 / "data-more =" Read the definition ">speed in the infinity of 3,475 meters per second and a declination of – 3.8 degrees. It will take seven years for the probe and nine gravitational assistance maneuvers (one around the globe structure … "data-image =" / midioriginal /8/4/e/84ff7edce5_123534_terre-apollo8.jpg "data-url =" / planet / definitions / structure-earth-land-4725 / "data-more =" More information ">land, two around Venus and you are around Mercury) to reach the planet Mercury and to orbit around.

Upon arrival near Mercury, the probe BepiColombo it will be subjected to a radiative environment so intense that the satellite will experience temperatures above 350 ° C with local exposures of the antenna reflector at more than 400 ° C.

To protect itself from these temperatures, which could dissolve any component or instrument of the probe, Airbus Defense & Space entrusted Thales Alenia Space with the realization of the thermal protection of the satellite, " the true challenge of the mission Explains Paolo Musi, the head of Thales Alenia Space's scientific programs. It is designed to guarantee a temperature range of operation of the electronics inside the satellite, less than 40 ° C when the satellite is exposed to a flow of heat from the Sun more than 14 kilowatts / m2, about 10 times the solar flux observed in the Earth's orbit "In these environmental conditions, the outer surface of the satellite will exceed 400 degrees Celsius "Added to this constraint is another, all the exhibited materials will also have" resist the intense ultraviolet radiation and the flow of solar charged particles without degradation ".

Resist extreme temperatures: the true challenge of the mission

The success of the mission depends in part on the proper functioning of this thermal control system, " which keeps all components and instruments within an acceptable range of temperatures below 40 degrees Celsius "Thales Alenia Space has therefore developed highly innovative specific technical solutions such as external multilayer insulation, ceramic, dielectric coatings and high temperature mechanisms for the external antenna and solar panels.

At the same time, near Mercury and the Sun is the closest star to the Earth, from which it is about 150 million kilometers. The Sun is 8.5 kparsec from the center of the Milky Way. In the classification of stars, the sun is a star of type G2.
The mass … "data-image =" "data-url =" / sciences / definitions / universe-sun-3727 / "data-more =" More information ">Sun, the European MPO orbit (Planetary Orbit of Mercuryr) is the form that " will suffer the strongest thermal stress Compared to the MMO hormone (Magnetospheric mercury orbit), supplied by Japan. The DFO will revolve around Mercury in a low elliptical low orbit, at an altitude of 480 km to 1,500 km, while the Japanese MMO will be positioned in a polar elliptical orbit, 600 km for 11,800 km. To effectively protect the MPO orbit from light and solar radiation, it is equipped with all sides, except one, of an external multilayer insulation (MLI) of a thickness of about 60 mm, specially designed for BepiColombo, with an external thermal shield in Nextel and titanium sheets ".

On the side of the DFO that will never see the Sun, Thales Alenia Space has not installed the insulation but a thermal radiator, designed to dissipate the heat produced internally from the equipment outside the orbit but also the one that succeeds in sneaking from the MLI "However good, this multi-layered insulation still allows the heat to pass through the satellite, which adds to the calories produced by the instruments and the on-board electronics. the operation requires a temperature range between 0 and 40 degrees Celsius ".

As for the external elements, such as the antenna reflector, which will be directly exposed to the sun, they are protected by special white coatings, " ceramic or dielectric materials "Despite these reflective coatings, they the temperature will exceed 400 degrees Celsius "!

Always closer to the sun

Although these thermal protections have been specially developed for BepiColombo, some of the technological and design solutions will be " useful to Solar Orbiter heat shield that we will achieve "However, the Solar Orbiter heat shield required a change of technology. because the probe will be even closer to the Sun than BepiColombo and can reach temperatures up to 550 degrees Celsius "Solar Orbiter will arrive in fact at 42 million kilometers from the Sun against only 58 million kilometers for BepiColombo!

What to remember

  • Mercury is the smallest and least explored telluric planet in our solar system.
  • The arrival of BepiColombo around Mercury is expected by the end of 2025, after a seven-year journey and nine gravitational assists (one around the Earth, two around Venus and six around Mercury).
  • Due to the proximity of Mercury to the Sun, the BepiColombo probe is equipped with a specific thermal protection by Thales Alenia Space.

BepiColombo: launch of a new probe to unlock the secrets of Mercury

Article of Rémy Decourt published on 10/19/2018

In the night between Friday and Saturday, Arianespace is responsible for the commercial operations of … "data-more =" / sciences / definitions / univers-arianespace-3453 / "data-more =" More information ">Arianespace it will inject BepiColombo into a hyperbolic release orbit for a meeting with the planet Mercury that will reach after seven years of space travel. This spacecraft of the European Space Agency is a gateway to space for Europe. Its mission is to shape the development of European space capabilities and … "data-image =" / f /09f0b05e28_50034401_logo-esa-fs.jpg "data-url =" / sciences / definitions / univers-esa-2466 / "data-more =" More information ">ESA and Jaxa is the first mission of these two agencies in Mercury. It is an interdisciplinary mission that aims to send two space probes to Mercury, the maximum little planet of our Solar system and also the least explored.

After the successful launch of Satellite Eolo study of windArianespace is preparing to launch, on Friday night to Saturday, the BepiColombo probe in Mercury. If for Aeolus, Arianespace had used In general, a launcher is made up of different phases (rocket or composite rocket).
Each phase includes: • one or two tanks (fuel and oxidizer) or … "data-more =" / sciences / definitions / universe-launcher-2059 / "data-more =" More information ">thrower Vega to inject it into a low orbit around the Earth, to put BepiColombo on the road to Mercure, Arianespace will use an Ariane 5 ECA, which has just completed its penny launch.

The launch, scheduled for Saturday, October 20 at exactly 3:45:28, Paris time, so at night from Friday to Saturday, is follow live on the ESA website.

This probe is a joint mission between European and Japanese space agencies. It was built by Airbus Defense & Space, head of a consortium of 83 companies from 16 countries, with Thales Alenia Space as the main industrial partner providing the main thermal control technologies that represent the real challenge. the mission.

In fact, it must be known that because of the near Mercure in the sun, about 58 million kilometers, BepiColombo will have to withstand extreme temperatures. It will be exposed to temperatures of 300 ° C with local exposures of the antenna reflector at 400 ° C while instruments and electronics are designed to operate at temperatures between 0 ° C and 40 ° C C. We will have the opportunity to return to it in more detail.

BepiColombo has the distinction of being composed of several modules (three of which are provided by Europe):

  • MPO orbit (Mercury Planetary Orbiter), with its 11 tools dedicated to global cartography and the study of the surface of Mercury, with regard to its shape, its internal structure, its geology, the science of the Earth
    Geology is a scientific discipline focused on the outer layers of the Earth, in particular on their structure, … "data-image =" midioriginal / 3 / d / 7 / 3d738ba741_45745_def-geology-bonacherajf-flickr.jpg "data-url =" / planet / definitions / structure-earth-geology-13943 / "data-more =" More information ">geology, its composition and its craters, and its atmosphere ;
  • the sun shield, to protect the machine from about 350 ° C near Mercury;
  • the MTM transfer module (Mercury Transfer Module), intended to bring the two orbitants to the Mercury region. It will provide power and propulsion for the Terra-Mercury trip;
  • the MMO orbiter (Mercury Magnetospheric Orbiter), supplied by Japan, is optimized to study the Mercury environment. It will study magnetic field, magnet and field … "data-image =" jpg "data-url =" / sciences / definitions / physics-magnetic field-3878 / "data-more =" More information ">magnetic field of Mercury and the vestiges of its atmosphere thanks to its five instruments.

A journey of seven years before unveiling the secrets of a surprisingly unknown planet

The arrival of BepiColombo around Mercury is expected by the end of 2025, after a seven-year journey, when BepiColombo, after dropping the MTM, will be subject to the gravitational field of the planet. A scientific mission of a will therefore begin duration year, with a possible extension of a further year with, as main scientific objective, the conduct of a systematic and in-depth observation of the planet, including the analysis of its surface and its magnetosphere. The goal of the launch of Ariane 5 (VA-245) is to inject BepiColombo into a hyperbolic release orbit for an appointment with the planet Mercury with as parameters an infinite speed of 3.475 meters per second and a declination of – 3.8 degrees.

BepiColombo will also try to better understand the history of its magnetic field and its volcano: what is the difference between lava and magma?
The morphologies created … "data-image =" "data-url =" / planet / definitions / volcanology-volcanism-972 / "data-more =" More information ">volcanism as well as water ice deposits that have been found at the bottom of many craters. Remarkable feature, it will be the first probe around this planet to be able to permanently aim at nadirthat is vertically, exactly below it.

To learn more about the technical difficulties of the mission and the details of the scientific objectives, we invite you to reread theinterview with François Leblanc, Latmos planetologist and scientific leader of one of the instruments, completed in July 2017.

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