Ariane 6 vs Ariane 5: Running in Place or a Step Forward?

Competition is the driver of progress, not only on Earth but also in space. Even if you are the leader in the payload launch market today, without constant technology improvements, you risk becoming an outsider.

This was the fate that befell ESA in 2023, when it delayed the upgrade of its flag launcher Ariane, causing a crisis in European access to space. In July 2024, the error was corrected and the long-awaited sixth version carried out its first mission. But can it become a worthy successor to the family?

In our recent article we compared the success odds of Ariane 6 vs Space X Starship and Falcon 9, and they were not in favour of the ESA rocket. Today, we will conduct a comparative analysis of the Ariane 6 Vs Ariane 5 improvements to finally answer the question of what is Ariane 6: running in circles or a step forward?

What is Ariane 5?

The history of European launch vehicles dates back to 1979. That was when the European Space Agency proved its right to be an independent entity in the space services market by introducing the first rocket modification 1 to the world. 17 years later, the titanic work of aerospace engineers and technicians from 20 European countries transformed into one of the most successful launch vehicles in the world, Ariane 5. Its creation took 10 years and cost a record 7 billion US dollars. For comparison, the projects of the same class of rockets Atlas V from Lockheed Martin and Delta 4 from Boeing cost 0.5 and 2 billion dollars. But unlike them, the fifth rocket modification had to be developed practically from scratch. It looked adventurous, but it justified itself.

The main improvements over the fourth version, which was nearly fault-less at the time, were a reduction in the number of stages, the addition of side solid boosters to increase thrust, the ability to re-ignite the second stage engine, and most importantly, a reduction in launch costs by an average of 20%.

Initially, Ariane5 had been intended for launching the Hermes manned spacecraft, but this idea was abandoned, and the launcher was used exclusively for unmanned missions. At the same time, the rocket was constantly being improved. Over 20 years, ArianeGroup released five versions of the rocket (G, G+, GS, ECA, ES), each of which included certain improvements.

In particular, thanks to various payload container options, the rocket could simultaneously launch two-three satellites and up to eight microsatellites into orbit. It was also used to deliver cargo to the ISS using automated cargo vehicles (ATVs), and in 2021, it launched the famous James Webb telescope into orbit.

During its 27 years of operation, the rocket made 117 launches, of which only two were completely unsuccessful (one of them the first) and three were partially unsuccessful. The launcher was most often used in the ECA (Evolution Cryotechnique type A) version with a cryogenic first stage to launch a 10.8-tonne payload into geostationary transfer orbit.

Despite the successful statistics, the launcher had two significant drawbacks that predetermined its future fate — low payload capacity for a heavy lift vehicle and high launch cost. ESA understood that this rocket could not compete with new American launchers, and decided to release Ariane 6.

Why did developing Ariane 6 take so long?

Ariane 5 was supposed to be replaced by Ariane 6 back in 2020, but a cocktail of epidemics, wars, inflation, and poor planning led to a delay that knocked ESA out of the leading launchers’ cohort.

The fifth version was not only technologically outdated, it could not meet ESA’s ambitions to double the annual number of launches (from 6 to 12). Traditionally, it launched only from Kourou and required long technical gaps between launches. The sixth version was designed to address this and other shortcomings, but it was developed too slowly. In addition to the above-mentioned problems, during the rocket’s qualification phase, Arianespace engineers discovered a number of problems that had to be fixed before launch.
As a result, the final decommission took place in 2023, and ESA had to rely on Space X to deliver European satellites into orbit for almost another year while waiting for the sixth  rocket version. On July 9, 2024, Ariane 6 finally completed its first commercial mission, and now ESA is pinning all its hopes on it. Let’s take a look at the Ariane 5 vs Ariane 6 specs comparison table to find out how justified these hopes are.

Ariane 5 vs Ariane 6: main features  

So was the substitution worth it?

So, Ariane 6 vs 5 is not a radically new invention, as was the case with the fifth and fourth versions, but it has received a number of significant improvements. The payload mass has been almost doubled, and the launch cost has been reduced by 40%. Besides, the option to launch payloads on a translunar trajectory has been added, done with a clear aim at Europe’s participation in the new lunar programme Artemis.

It would seem that ESA has made an obvious step forward, but Ariane 6 problems can already be seen. The lack of reusability, like Space X Falcon 9, archaic boosters with toxic fuel, and a clearly underestimated launch cost. ESA has fundamentally rejected the idea of reusable Ariane 6, emphasizing that with 10-12 launches per year, there is no point in spending money on a retrieving first stage. As for the launch cost of 70 and 90 million for different modifications, Pacome Revillon, CEO of the consulting company Novaspace, calls this figure too optimistic and believes that the lower limit will exceed 100 million euros.

However, ESA does not even try to deny its miscalculations. Tony Tolker-Nielsen, the head of the Ariane6 programme, openly stated that the rocket “6 is no longer competitive with Falcon 9, this we have to face.” On the other hand, ESA astronaut Thomas Pesquet emphasised the rocket’s importance for the European launch market. “No matter how you look at it,” Pesquet said before the carrier’s first launch, “this rocket is fundamental for Europe’s autonomous access to space. Space has become so important that we simply can’t let others launch our own satellites.”

So, if the business case for replacing the fifth version with Ariane 6 used to be obvious, now it is based on space geopolitics. And while companies like Space X are bringing us closer to the stars by leaps and bounds, the European space industry continues to run in circles and doesn’t seem too concerned about it.

References and Additional Information:

• Ariane 6 overview https://www.esa.int/Enabling_Support/Space_Transportation/Launch_vehicles/Ariane_6_overview
• Ariane 6 https://www.Arianespace.com/vehicle/Ariane-6/
• Orbital rockets https://nextspaceflight.com/rockets/
• Ariane 5 The heavy launcher  https://www.Arianespace.com/vehicle/Ariane-5/
• Ariane 5 https://www.esa.int/Enabling_Support/Space_Transportation/Launch_vehicles/Ariane_5