50 years of ESA (1975-2025): Missions and projects

By pooling financial and intellectual resources, the ESA is able to realize projects that are unattainable for individual member states. ESA also works closely with European (DLR, NLR, CNES, etc.) and international space agencies (including NASA, the Japan Aerospace Exploration Agency (JAXA), and the Indian Space Research Organisation (ISRO)). Among other things, ESA is responsible for the development of the Ariane rockets, which are used to launch artificial satellites into space. A selection of the Ariane rockets and missions is discussed.

Guiana Space Centre (CSG)

The Centre Spatial Guyanais (CSG) at Kourou in French Guiana is the launch center of the European Space Agency (ESA). Among others, the Ariane rockets of ESA and Arianespace are launched from here. Kourou is located just 500 kilometers from the equator, making it the most favorably situated launch base in the world for many launches. Due to the Earth's rotation, a rocket gains an extra 460 meters per second of speed here when launching in an easterly direction. Furthermore, it is easier to place satellites into orbits above the equator from this location. An additional advantage of Kourou's location is that the launch runway is situated over the sea, ensuring there are no risks to the population in the event of a launch failure.

Map of the European launch base (Centre Spatial Guyanais of CSG) in Kourou, French Guiana. Source: NielsF, Pline / Wikipedia.

On December 24, 1979, the first Ariane 1 rocket was launched from launch pad ELA-1. This launch pad had been converted from its previous function as the launch pad for the Europa 2 to the Arianespace 1 and was later also adapted for Ariane 2 and Ariane 3 rockets. For the launch of the much larger Ariane 4 rockets, a new launch pad, ELA-2, was built, which was used on July 15, 1988, for the first launch of an Ariane 4.

A new platform, ELA-3, was built for launching Ariane 5 rockets. The first Ariane 5 was launched from this platform on June 4, 1996. The launch was a fiasco due to errors in the launch software, but many successful launches with Ariane 5 have been carried out since that period. The most famous of these was the launch of the James Webb Space Telescope on December 25, 2021.

In September 2021, the launch complex (ELA-4) for the launch of Ariane 6 opened. The main elements consist of the launch pad with two exhaust channels, the mobile portal, and the launch vehicle assembly building. The final integration of Ariane 6 takes place in the mobile portal, just as is the case with Soyuz and Vega.

Ariane rocket

The Ariane is a series of launch vehicles of the European Space Agency (ESA). In French, Ariane stands for Ariadne, the figure from Greek mythology. The rocket is named after this French name. The Ariane rockets are launched from the Centre Spatial Guyanais (CSG) at Kourou in Frans-Guyana.

Lancering Ariane 5 vanuit Kourou, Frans-Guyana.

The Europa Rocket was the first attempt by European countries in the 1970s to build their own launch vehicle. To this end, a number of European countries united in the European Launcher Development Organisation (ELDO) established the Europa Launcher Programme, but this program did not progress beyond the development stage. France subsequently started its own launch vehicle program. After the ELDO merged into the European Space Agency (ESA) in 1975, the project was taken over by ESA, resulting in the Ariane rocket.

An example is the Ariane 4 rocket family, which was used between June 15, 1988, and February 15, 2003. Development of the Ariane 4 began in 1983, and the first successful launch took place on June 15, 1988. In total, 104 successful missions and three failed launches were carried out with this version of the Ariane rockets. Compared to the Ariane 3, the payload capacity of the Ariane 4 was increased by 1700 kg to a maximum of 4800 kg at geostationary altitude. The record mass for the Ariane 4 at geostationary altitude stands at 4946 kg.

The rocket came in various variants; two to four additional booster rockets with solid-fuel or liquid-fuel engines could be attached to it. The complete launch system also consisted of a satellite carrier system called Spelda (derived from the French *Structure porteuse externe pour lancements doubles Ariane*), which allowed multiple satellites to be launched simultaneously.

Ariane 4 AR 40 was the base version, which consisted of three stages. The rocket was 58,4 m tall, with a diameter of 3,8 m, a launch mass of 245 tonnes, and a maximum payload of 2100 kg to geostationary altitude or 5000 kg to low orbit. The main power came from four Viking 5 engines, each delivering 667 kN of thrust. The second stage had a single Viking engine, and the third stage had a liquid oxygen/liquid hydrogen HM7 engine. The Ariane 4 AR 44L, with the maximum number of four additional booster rockets, consisted of four stages, had a launch mass of 470 tonnes, and a payload of 4730 kg to geostationary altitude or 7600 kg to low orbit.

Giotto (1985/1986)

Giotto was ESA's first 'deep space' mission and aimed to study Halley's Comet. The probe was named after the Italian painter Giotto di Bondone, who was likely inspired by the appearance of Halley's Comet in 1304 for his work "Adoration of the Magi".

The probe was shaped like a cylinder with a diameter of 1,85 meters, a total length of 2,85 meters, and weighed 960 kg. It was launched on July 2, 1985, aboard an Ariane 1 rocket from the Centre Spatial Guyanais near Kourou (French Guiana). Initially, Giotto was placed in a geostationary orbit. After circling our planet three times, Giotto's engine was started to place the probe into an interplanetary orbit, allowing it to fly past Halley's Comet in March 1986. The probe passed the nucleus at a distance of only 596 km (a record for that time). The images showed the nucleus of a comet for the first time, and data from the instruments indicated, among other things, that the comet was formed 4,5 billion years ago from condensing ice that created interstellar dust particles. The exact position of the comet nucleus and the approach course to be followed could be optimized using camera images from the Russian probes Vega 1 and 2, which served as scouts for Giotto.

Huygens (1997)

Huygens is a space probe of the ESA. This space probe was launched on October 15, 1997. Its final destination was Titan, Saturn's largest moon. The space probe was named after the discoverer of Titan, the Dutch astronomer. Christiaan Huygens, he discovered this moon in 1655.

The space probe was attached to the American space probe Cassini-Huygens, which entered an orbit around Saturn in July 2004 and conducts research there. Cassini-Huygens is the largest interplanetary space probe ever built (2004). The Cassini-Huygens combination weighs 5,6 tons.

The Huygens probe had a diameter of 2,7 meters with the shield and 1,3 meters without it. The hard shield protected the vulnerable probe from the extreme temperatures that occurred during descent into Titan's atmosphere.

In 2005, ESA's Huygens probe parachuted through the atmosphere of Saturn's largest moon to land on the surface of TitanThe Open University led the Huygens Surface Science Package, which included a sensor built by the British that became the first Huygens component to touch the surface of Titan. The image on the stamp was created en route to this historic encounter.

Illuminated by the sun behind it, the beautiful icy rings of Saturn photographed by the Cassini probe. Cassini-Huygens has radically changed our knowledge of it and discovered new rings and moons. British universities and industry have contributed to many of the instruments on both parts of the mission.

Rosetta (2004/2014)

Rosetta was a space probe funded by the ESA. Rosetta was placed in orbit around Comet 67P/Churyumov-Gerasimenko in 2014 to study it. In the first years after its launch in 2004, Rosetta orbited the Sun several times. During these orbits, it passed Earth and Mars several times and used a gravitational slingshot to gain speed. Afterward, the space probe went into “hibernation” for several years, until a few months before reaching its final destination.

A crossing with Mars, during which no sunlight could be captured, was not foreseen but became inevitable in late February 2007 when the planned launch had to be postponed. As a result, batteries had to power the systems, even though they were not designed for this. There was no contact between the probe and Earth for fifteen minutes. During the flyby, the probe was located about 250 kilometers above the red planet.

Rosetta reached an orbit around the comet in 2014 and conducted research for two years. The probe also studied how the comet's coma (the “tail”) developed as it approached the Sun. On November 12, a lander named Philae detached from the spacecraft with the goal of landing on the comet. Shortly after 16:30 PM Central European Time, Philae landed on the comet and sent a confirmation message that was received on Earth half an hour later. To prevent the lander from bouncing back into space after landing due to the comet's very low gravity, Philae was intended to anchor itself to the surface immediately after landing using three ice screws and two harpoons. However, Philae bounced back twice; neither the ice screws nor the harpoons functioned as expected.

On its way to an encounter with Comet Churyumov-Gerasimenko, the ESA probe Rosetta made a close encounter with the asteroid. Lutetia, located in the asteroid belt between the orbits of Mars and Jupiter. Rosetta reached the small, rhombus-shaped asteroid at a distance of only 800 kilometers.

The Rosetta space probe is named after the Rosetta Stone, which was found in 1799 near the Egyptian town of Rosetta. This stone formed an important key to deciphering Egyptian hieroglyphs.