On July 5, 2023, Arianespace’s Ariane 5 launched for the final time, closing out the rocket’s long tenure that began with its first launch in 1996. This heavy-lift launch vehicle was a workhorse for both the European and global space communities, launching payloads to Low Earth Orbit (LEO) and Geostationary Transfer Orbit (GTO). Its 117 launches over more than 20 years boasted a 96 percent success rate, making Ariane 5 one of the more reliable launchers on the market. 

Ariane 5’s history was central to the story of 21st century spaceflight, and indeed, the rocket drew from a long history stretching back decades. The work for the first Ariane launcher—Ariane 1—began in the mid-1970s, when western European countries increasingly sought to integrate their spaceflight ventures, leading to the founding of the European Space Agency (ESA).  

One of ESA’s early projects—building on the long-time French priority—was the development of a European launch vehicle. Such a rocket would give Europe independent access to space, and thereby lower its reliance on the two superpowers, most often the United States. The French space agency (CNES, National Centre for Space Studies, Centre national d'études spatiales) and industry partners from France and other European states including Sweden and West Germany developed Ariane 1. ESA then formed the private company Arianespace to manage the commercialization of the Ariane rocket program. This organization made Ariane an early player in the history of commercial launchers. 

Ariane 1 was followed by updated versions Ariane 2, 3, and 4. The series enjoyed notable success, launching half of global commercial satellites at the time. Work on Ariane 5 began in January 1985, and its first launch took place in 1996. Like its predecessors, Ariane 5 introduced improvements over Ariane 4. Most importantly, it could launch a heavier payload at lower costs. 

The design of Ariane 5 consisted of two side boosters attached to a two-stage liquid-fuel launcher. The boosters burned for 130 seconds before separation and provided over 90 percent of the launcher’s total thrust in early flight. During launch and the initial ascent, a single Vulcain 2 engine also fired, burning propellants housed in the first stage. After stage one separation, the upper stage was powered by an HM7B engine, the same upper-stage engine as Ariane 4. Ariane 5 could launch payloads weighing more than 22 tons (20 metric tons) to LEO and 11 tons (10 metric tons) to GTO. 

Ariane 5 launched at a cadence of around a half dozen times per year, mostly delivering communications satellites to GTO. At times, Ariane 5 was also chosen to launch missions beyond GTO. In 2004, an Ariane 5 launched Rosetta and its Philae lander to an Earth escape orbit, setting them on their way for a journey to the comet 67P/Churyumov–Gerasimenko, on which Philae ultimately landed. Ariane 5 also launched two space telescopes to the second Lagrangian point (L2), which provides a stable orbit with unobstructed views out into the universe. The first was ESA’s Herschel Space Observatory. The second was the James Webb Space Telescope, the largest optical telescope in space, which launched in December 2021. Ariane 5’s penultimate payload contained Juice (Jupiter Icy Moons Explorer), which launched in April 2023 on a mission to study three of Jupiter’s moons thought to have liquid water—Ganymede, Callisto, and Europa. 

The retirement of Ariane 5 leaves a gap in ESA’s launch capabilities, which will be filled by Ariane 6. It is currently expected to launch for the first time in 2024. In development since the 2010s, Ariane 6 promises a lower launch cost than its predecessor. It will have two versions—Ariane 62 for institutional missions and Ariane 64 for the commercial market. An upgraded Vulcain 2.1 engine and a new Vinci engine will power the liquid-fuel stages. Planned Ariane 6 launches include the Earth Return Orbiter for the NASA-ESA Mars Sample Return Mission.