Ariane 5 retires: its best missions

On July 5, the last Ariane 5 will launch from Europe’s spaceport in Kourou. This heavy launcher, a flagship of the European space industry, has provided Europe’s access to space since 1997. After this hundred and seventeenth launch, Ariane 5 will retire. It will soon be replaced by Ariane 6, which is more powerful and more versatile while being less expensive, with a first launch scheduled for the end of 2023.

Ariane 5, thanks to its enormous capacity and its precision, has made it possible to send many international missions into space, both in the field of telecommunications and in the observation and exploration of the universe.

Here is our “top 8” missions sent by Ariane 5.

On April 14, 2023, the European mission JUICE (Jupiter Icy Moon Explorer) set off on an Ariane 5, which is to join Jupiter and its icy moons in eight years to study them and answer big questions: What are the conditions who preside over the formation of the planets and the emergence of life? How did the solar system originate?

After more than 20 years of work, NASA and its partners, ESA and CSA, watched with immense relief as Ariane 5 launched the James Webb Space Telescope with pinpoint accuracy on December 25, 2021 – a great Christmas gift for anyone. the international scientific community.

Often referred to as the successor to the iconic Hubble space telescope, the James-Webb is rather complementary to it. By observing in the infrared with excellent image quality, it finally gives scientists access to the very distant universe, the seat of the formation of the first objects… As well as to closer and smaller objects such as interstellar clouds. , where stars are formed but which are opaque to Hubble, exoplanets and even an unprecedented vision of objects in our solar system.

NASA is already thinking about the future large space observatory that will be built on the Webb’s shoulders: the Habitable Worlds Observatory.

On October 19, 2018, BepiColombo was thrown out of the Earth’s gravity field by an Ariane 5 rocket.

She then embarked on a 7-year cruise to the planet Mercury, during which she will revolve 18 times around the sun, relying on the force of attraction of the Earth (once), Venus (twice), and Mercury itself (6 times). These overflights have already enabled him to capture new images on the fly.

At the end of the journey, two probes, one European and one Japanese, will be inserted into orbit around Mercury on December 20, 2025. They will jointly study its magnetic field, the existence of which, on such a small planet, is an enigma. The composition of its very thin atmosphere will tell us about the formation of the protosolar disk: Was Mercury born closest to our star by a process of accretion or further away, before migrating towards it?

The craters of the polar regions will be scrutinized with great attention: the deepest of them could harbor water ice brought by comets. To solve these mysteries, thanks to four layers of multi-ply insulating blankets and radiators protected by Venetian blinds, it will be necessary to withstand external temperatures of 450°C and radiation from the nearby sun.

Providing a global positioning service, Galileo is based on a constellation of 30 satellites orbiting at an altitude of 23,222 km. It displays an accuracy of less than one meter anywhere on the planet. This program allows Europe to be independent in the field of satellite navigation (Global Navigation Satellite System), in parallel with the American GPS system, the Russian GLONASS system and the Chinese BEIDOU system.

Thanks to three launches from 2016 to 2018, Ariane 5 put twelve Galileo satellites into orbit, which currently represents half of the operational satellites. The other half of the constellation was also orbited by Arianespace from Kourou with Soyuz rockets before 2016 and in 2020. This increased Ariane 5 orbiting capacity enabled the accelerated speed populating of the Galileo constellation in for the provision of operational services which were initiated at the end of 2016.

The Ariane rocket has been adapted to launch four Galileo satellites simultaneously: the “Ariane 5 Evolution Storage” version allows the re-ignition of the upper stage and therefore an injection of the satellites very close to the final orbit. This capability was essential given the limited amount of propellant that these satellites can carry.

There are ten first-generation Galileo satellites to be placed in orbit – the future Ariane 6 should contribute to this.

Ariane 5 succeeded on a mission of capital importance for Europe on May 14, 2009: the launch of not one, but two ESA telescopes, Herschel and Planck telescopes, respectively dedicated to the study of the cold universe. and the cosmic microwave background.

Equipped with the largest monolithic space mirror to date (diameter of 3.5 meters) and ultra-cooled sensors, Herschel observes cold radiation sources for three years to explore, for example, interstellar dust clouds and their dynamics, the history of star formation in galaxies over the ages.

The radiation observed by Herschel is inaccessible to ground-based telescopes, and the mission, completed in 2013, has therefore brought a harvest of results and sumptuous images: clouds of water brought twenty-five years earlier into the Jupiter’s atmosphere by the collision of comet Shoemaker-Levy 9, star nurseries within filaments of dust and gas, cradles for the formation of planets and comets around other stars, the omnipresence of water in the universe.

Herschel’s success is such that the international scientific community is now working to find a successor. NASA, which had contributed to Herschel, should issue a dedicated mission call in 2023.

To resupply the International Space Station, ESA has designed a dedicated spacecraft: the European Automated Transfer Vehicle, or “ATV”. It can carry up to eight tonnes of equipment (oxygen, fuel, drinking water, food, scientific equipment) and made five flights between 2008 and 2015.

On March 2, 2004, aboard an Ariane 5 in its G version, the European probe Rosetta left Earth for a 10-year journey, bound for comet Tchoury – whose real name was 67P/Churyumov-Gerasimenko.

For this ten-year journey, with more than four laps around the Sun, Rosetta carries two tons of fuel, or two thirds of its total mass.

The Rosetta mission to comet Churyumov-Gerasimenko. Source: CNES.

In August 2014, Rosetta finally arrived near Tchoury. She will study it for two and a half years and drop a small lander, Philae, on November 14, 2014. These analyzes revealed that the comet, far from being a “dirty snowball” as described by Fred Whipple, consists of equal parts of ice (mainly water), organic matter and silicate minerals. Rosetta analyzed more than sixty molecules, including the amino acid glycine.

From this mission, we will remember that the water of the Earth probably does not come from comets, but that the carbonaceous molecules, they, would perhaps have a cometary origin.

On December 10, 1999, during its first commercial flight, Ariane 5 placed a revolutionary telescope into a high elliptical orbit. Sized to completely fill the fairing of Ariane 5, it will remain the largest telescope ever launched into space until 2021, and was only recently dethroned by the famous James-Webb space telescope.

XMM-Newton is dedicated to the observation of X-radiation in the universe, coming from black holes in the act of material accretion, from stars at the end of their life or going through cataclysmic episodes, from hot gases bathing the clusters from galaxies, neutron stars, to the aurora borealis of the giant planets of our solar system.

Equipped with three telescopes capable of focusing and measuring X-rays – ultra-energetic radiation that is particularly difficult to deflect and stop, XMM-Newton floods the scientific community with images and spectra of several hundred thousand cosmic sources. The mission was for a long time the most productive of ESA’s scientific missions, in terms of scientific publications – until the advent of Gaia in 2018. Today, XMM-Newton is still working perfectly.

Francis Rocard, Planetologist, Head of Solar System Exploration Programs, National Center for Space Studies (CNES); Jean MARECHAL, Navigation and Localization Program Manager, National Center for Space Studies (CNES); Olivier Joie-La Marle, Head of the Universe Sciences Program, National Center for Space Studies (CNES) and Pierre Bousquet, Deputy Deputy Director of Exploration and Human Flight Projects, National Center for Space Studies (CNES)

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