The project’s primary contributors were France (55%), Germany (21%), and Italy (7.6%), with the remaining work distributed among ten other participating countries.

While the rocket successfully launched, the mission experienced a partial failure when the upper stage malfunctioned and was not able to complete its final deorbit burn.

European officials defend the program, saying it provides crucial independent space access for its member states.

It will use more powerful P160C model solid rocket boosters and increase thrust of the Vinci engine in the upper stage to 200 kN.

The payload fairing, constructed by Beyond Gravity from a carbon fibre-polymer composite, is designed as a nose cone that splits vertically into two halves at the top of the Ariane 6 rocket.

Development funding from several European governments was secured by early 2016, and contracts were signed to begin detailed design and the build of test articles.

[25] In October 2020, the European Space Agency (ESA) formally requested an additional €230 million in funding from the countries sponsoring the project to complete development of the rocket and get the vehicle to its first test flight, which had slipped to the second quarter of 2022.

[37] The SpaceX Falcon 9 and the Chinese Long March 3B both launch smaller payloads but at lower prices, approximately $57 million and $72 million respectively as of early 2014, making the Falcon 9 launch of a midsize satellite competitive with the cost of the lower slot of a dual payload Ariane 5.

[37] In June 2014, Airbus and Safran surprised ESA by announcing a counter proposal for the Ariane 6 project: a 50/50 joint venture to develop the rocket, which would also involve buying out the French government's CNES interest in Arianespace.

The proposal also included simplification of the industrial and institutional organisation along with a better and cheaper version of the Vulcain 2 engine for the main stage.

[53] The horizontal assembly process was inspired by the Russian tradition for Soyuz and Proton launchers – which had more recently been applied to the American Delta IV and Falcon 9 boosters[54] – with a stated goal of halving production costs.

[56] Ariane 6 was to be the first large rocket to use a laser ignition system developed by Austria's Carinthian Research Center (CTR), that was previously deployed in automotive and turbine engines.

[58] Reorganisation of the industry behind a new launch vehicle, leading to the creation of Airbus Safran Launchers (ASL), also started a review by the French government into tax matters, and the European Commission over a possible conflict of interest if Airbus Defence and Space, a satellite manufacturer, were to purchase launches from ASL.

indicating that reusing the first stage was economically unviable as manufacturing ten rockets a year was cheaper and more feasible than recovery, refurbishment and loss of performance caused by reusability.

Rather than developing a way to reuse an entire first stage (like SpaceX), Airbus proposed a system where only high-value parts would be safely returned using a winged module at the bottom of the rocket stack.

Charmeau was non-committal about whether Prometheus (still only in the first few months of development) could be used as an expendable replacement for the Vulcain 2 in Ariane 6, or whether it was tied to the re-usable Adeline design, saying only that "We are cautious, and we prefer to speak when are sure of what we announce...

But certainly this engine could very well fit with the first stage of Ariane 6 one day", a decision on whether to proceed with Prometheus in an expendable or reusable role could be made between 2025 and 2030.

The Ariane NEXT initiative includes a reusable sounding rocket, Callisto, to test the performance of various fuels in new engine designs.

[69] In a January 2019 interview, Arianespace CEO Stéphane Israël said that the company would require four more institutional launches for Ariane 6 to sign a manufacturing contract.

In response, ESA representatives said the agency was working on shifting the 2022 launch of the Jupiter Icy Moons Explorer from Ariane 5 ECA to Ariane 64, further indicating that there are other institutional customers in Europe that must put their weight behind the project, such as the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) or the European Commission.

[73] Rocket components are transported by sea from Europe to the Guiana Space Centre aboard the Canopée, a cargo vessel that uses sails to assist with its propulsion, reducing fuel use.

[122] A major criticism of the Ariane 6 stems from its reliance on expendable technology at a time when competitors have demonstrated the economic advantages of reusability.

For example, SpaceX iteratively developed its Falcon 9 rocket, nearly doubling its payload capacity and making it partially reusable, lowering the company's costs to launch.

They point to geopolitical disruptions, such as losing access to Russian Soyuz-ST rockets, as evidence of the necessity for a self-reliant European capability.

Officials have also justified the rocket’s lack of reusability by arguing that the relatively low number of planned launches would make such a feature economically unviable.

[124][125] To support the programme, ESA's member states have agreed to subsidise the Ariane 6 with up to €340 million annually from its 16th to its 42nd flight, expected to occur by 2031.