As the inaugural flight of Ariane 6Ariane 6 approaches rapidly, scheduled for the end of June, Futura had the opportunity to speak with Toni Tolker-Nielsen, the Director of Space Transportation at ESA. At the core of this discussion is the technical analysis of the Ariane 6 program and the challenges faced throughout its eventful development. Dive into the behind-the-scenes of this emblematic project and discover Toni Tolker-Nielsen’s fascinating insights on innovations, technical difficulties, and future prospects for space transportation.
Futura: From a technical standpoint, how do you view the Ariane 6 program?
Toni Tolker-Nielsen: From a technical perspective, although the overall architecture of Ariane 6 is similar to Ariane 5, several major differences should be highlighted. Firstly, the boosters differ from the Ariane 5Ariane 5 EAPs in terms of their smaller size and reduced weight. Derived from the Vega P80, these boosters (P120) are used in both the Ariane 62 version with two boosters and the Ariane 64 version with four boosters, as well as Vega CVega C as the main stage. The P120 is also the largest monolithic solid propellant engine in the world.
Another significant difference between Ariane 6 and Ariane 5 lies in its brand-new upper stage equipped with the restartable Vinci engine. This stage allows Ariane 6 to undertake missions that were previously impossible for Ariane 5.
I also want to emphasize the involvement of 13 countries in the Ariane 6 venture, as well as the fact that this launcher was designed for industrialization right from the beginning of its development, which was not the case for Ariane 5.
Futura: The delays and technical challenges encountered during the launcher’s development can be analyzed in various ways. How do you analyze them?
Toni Tolker-Nielsen: Since the development of a launcher of this scale occurs approximately every 30 years in Europe, it is inevitable to lose some of the acquired expertise, which then needs to be regained. This results in delays in the program’s launch. Additionally, inherent difficulties in any new development have also been faced.
Futura: From your perspective, what were the main technical issues encountered?
Toni Tolker-Nielsen: We encountered two main issues.This was the case with the development of cryogenic arms that connect the launcher to the launch pad. These arms are designed to supply the upper stage tanks with liquid hydrogen and liquid oxygen. The 13-meter-long cryogenic arms of Ariane 6 are larger than those of Ariane 5 which were 10 meters long. Unlike the cryogenic arms of Ariane 5, which were retracted before the Vulcain engine ignition, those of Ariane 6 remain connected to the launcher until liftoff. Moreover, they have been designed to retract extremely quickly to avoid any collision with the launcher during liftoff.
On the launcher side, we faced difficulties with the opto-pyrotechnic system, which replaces the traditional pyrotechnic systems used on Ariane 5. The use of laser power transmission caused many issues in the development of this optical system.
Regarding delays in the development of a launcher, Toni Tolker-Nielsen mentioned the importance of ensuring the availability of necessary technologies with a maturity level of 6 on the TRL scale at the beginning of any development project. This was not the case for the opto-pyrotechnic detonator, leading to consequences.
It is worth noting that the development strategy for Ariane 6 is based on qualifying the launcher under ground conditions before its first flight. Before the inaugural flight, all components and subsystems are thoroughly tested, validated, and modeled, covering each phase of the flight through a series of extensive tests on all elements of the launcher, including combined tests that lasted nine months. While this process takes time, it ensures a rigorous approach to qualify the launcher before its first flight. This differs from SpaceX’s approach, which relies on qualification flights for its launchers. It took SpaceX about a decade to progress from Falcon 1 to Falcon 9.
Toni Tolker-Nielsen emphasized the importance of quickly evaluating the maturity of technologies for effective technological risk management.
Significant Events Leading to the Decision to Subsidize Ariane 6 Operational Activity
Toni Tolker-Nielsen: Originally, the Ariane 6 program was aimed at operating without subsidies, unlike Ariane 5, which was funded with 120 million euros per year. However, during development, the situation changed due to increased competition, notably with SpaceX’s Falcon 9. When designing Ariane 6 in 2014, we based the launcher’s sizing and industrial organization on costs from that period. Unfortunately, the Falcon 9’s market prices significantly dropped due to the reuse of main stages, making it more competitive. Additionally, the rapid inflation in 2022 and 2023 was not accounted for in Arianespace’s commercial offers, impacting the launcher’s costs. This led to the decision to subsidize Ariane 6 with 300 million per year, operating nine launchers annually.
Could Ariane 6 Have a Shorter Operational Lifespan Compared to Ariane 5?
Toni Tolker-Nielsen: It’s challenging to predict the operational lifespan of Ariane 6 compared to Ariane 5. We faced similar issues with Ariane 5 when the first Ariane 5 failed in 2002. At that time, operational challenges were encountered with this launcher, while Ariane 4 dominated the market. There were doubts about the success of Ariane 5 initially. Eventually, the launcher became a market leader for commercial satellite launches into geostationary transfer orbit. In 20 years, I believe Ariane 6 will shine as brightly as Ariane 5 did.
Are There Improvements and Evolutions Planned for Ariane 6?
Toni Tolker-Nielsen: Absolutely. In collaboration with ArianeGroup, we are working on optimizing the Ariane 6 launcher. The competitiveness and adaptability of this launcher will be crucial to ensure its sustainability in the market, especially for mega-constellation launches. Planned improvements include increasing booster capacity from 120 tons.Ariane 6: a stage capable of bringing satellites to within the last kilometer of their position
Futura: Will Ariane 6 follow the model of Ariane 5, with identical launchers throughout extended series, or will it be able to evolve gradually over the course of its operation, like SpaceX’s Falcon 9 (especially for the first models)?
Toni Tolker-Nielsen: Like Ariane 5, the first series will be identical. However, small improvement programs are already planned to integrate the lessons learned from the launcher’s early flights. More concretely, it is envisaged that following the launcher’s commissioning, if the measurements confirm our expectations, it may be possible to eliminate the thermal protection between the heat flows of the thrusters and the Vulcain 2 nozzle, which could result in a saving of around a hundred kilograms.
Futura: Are the performances of the Ariane 6 launchers those planned when the program was launched, or have they been subject to revisions that make them different today?
Toni Tolker-Nielsen: No, they are the same up to the Ariane 6 block 2 version which could be in service from the end of 2025. Two flights are planned for 2024, followed by six flights for the year 2025 with the current version of Ariane 6.
Futura: Do you think the two versions of Ariane 6 will be sufficient to meet the needs of European institutional satellites?
Toni Tolker-Nielsen: Yes. For some exploration missions, such as missions to the Moon, Ariane 6 capabilities do not fully meet the identified needs. Currently, Ariane 6 can transport up to 9.9 tonnes to a transfer orbit towards the Moon. For example, increasing this capacity to around 12 tonnes would facilitate the launch of our lunar lander, Argonaut, which aims to deliver 1.5 tonnes of payload to the Moon.
Futura: Is a third version (which could be a smart stage, for example) being considered?
Toni Tolker-Nielsen: It is currently premature to make a decision. During our discussions with Daniel Neuenschwander, former head of launchers.Within the Agency, a consensus has been reached. We will consider the possibility of investing in significant modifications to the upper stages later on to achieve the planned 12-ton performance.
**Futura: With the expected boom in the space economy, what is your view on the future of space transportation (excluding manned flights)?**
**Toni Tolker-Nielsen:** We have examined several scenarios, and one that stands out involves using low Earth orbit as a hub for exchanging to higher orbits, including around the Moon and Mars, using space tugs to transport satellites to their destination. These spacecraft will not only be limited to transport services but will also be used for orbital services such as refueling. These space hubs can be compared to commercial port activities where containers are transported from one port to another before being distributed to their final destination by trucks or trains. The same concept is envisioned for space. Due to the high launch frequency expected, the launchers servicing these space hubs will need to perform recurring missions and be reusable. We are shifting paradigms with a high launch cadence, requiring a circular and sustainable economy. This implies that we will no longer use single-use launchers.
**Futura: Any final words?**
**Toni Tolker-Nielsen:** Building launchers is above all a passion. Projects like the development of Ariane 6 only come about once every 30 years in Europe! Developing a new launcher is an adventure in itself. Today, we are confidently approaching the final stretch after a decade of effort.
I also want to highlight that the Ariane launchers were designed within the European Space Agency. This initiative has not only provided Europe with autonomous access to space for the past 45 years but has also contributed to the development of a space and satellite industry that positions Europe as a leader in various markets, such as dual launches, launches into geostationary transfer orbit (GTO), and satellite construction for telecommunications. It has also boosted the growth of the European space industry in many other areas, such as Earth observation, navigation, scientific research, space sciences, and robotic exploration. The European space industry owes a lot to the Ariane program.