Ariane-6

Ariane 62 is a medium-lift launch vehicle that carries two P120C boosters, while Ariane 64, a heavy-lift version, carries four. It has been designed to improve the affordability of space launches, offer a more flexible launch vehicle to adapt to changing commercial and government demands, and ensure European strategic autonomy in space by reducing reliance on commercial space services such as SpaceX. The Ariane-6 launcher is poised to play a crucial role in supporting European space operations, providing a significant increase in payload weight capacity through larger and more powerful boosters. The launcher also incorporates an upper stage engine that can re-ignite itself multiple times, improving the efficiency of each launch by allowing multiple payloads to be inserted in different orbits. Another key innovation has been the introduction of 3D printed parts which reduce production time, cost, and waste. 1) 3) 4) 6) 11)

Technical Specifications

The Ariane-6 rocket is 93 m tall and 5.4 m wide. Ariane 62 has a mass of 530,000 kg, not including payloads, while Ariane 64 has a mass of 860,000 kg. Shown below are the maximum payload masses deliverable to a range of Earth orbiting, lunar injection, and Earth escape missions (Table 1), as well as their associated orbital parameters (Table 2). 1) 6)

Propulsion System

The Ariane-6 propulsion system consists of three components, the P120C boosters, the upper liquid propulsion module (ULPM), and the lower liquid propulsion module (LLPM). The first stage, the LLPM, is fuelled by a liquid hydrogen (LH2) and liquid oxygen (LOX) mix. The stage has a diameter of 5.4 m, and carries 140,000 kg of propellant. The Vulcain 2.1 engine (shown in Figure 1 below) powers the Ariane-6 cryogenic main stage. It runs on a gas generator cycle whereby a small portion of propellant is burned in a separate combustion chamber to power the turbopumps, which feed the main propellants into the main combustion chamber.

The engine has a vacuum thrust of 1,371 kN and a specific impulse of 432 seconds. Specific impulse is a key measure of rocket engine efficiency, defined as the ratio of thrust to propellant consumption. The combustion pressure for the engine is 118.8 bar, with a mixing ratio of 6.03 for its LOX-LH2 propellant mix. The engine turbopumps have a rotation speed of 12,300 rpm for the LOX tank and 36,500 for the LH2 tanks, while the engine itself has a propellant flow rate of 326 kg/s. This stage of the Ariane-6 rocket has a burn time of 468 seconds. 3) 4) 5) 7) 10) 11) 15) 16)

The first stage of the Ariane-6 rocket is assisted by the P120C boosters. These boosters are newly developed solid fuel engines derived from the original Vega launcher’s P80 first stage, with each booster using the same carbon fibre structural casing made from pre-impregnated epoxy sheets through a process of filament winding and automatic fabric deposition. Each booster is 13.5 m long and 3.4 m wide, carrying 142,000 kg of propellant. The boosters use a solid propellant mix of hydroxyl-terminated polybutadiene, ammonium perchlorate and powdered aluminium. The dry mass of each P120C booster is 11,000 kg, of which 8,300 kg is the motor case. The boosters provide an average thrust of 4500 kN, with maximum thrust of 4650 kN and a specific impulse of 278.5 seconds. Each booster has a burn length of 135 seconds. 5) 8) 10) 12) 13)

The second stage of the Ariane-6 rocket is the Upper Liquid Propulsion Module (ULPM), which is powered by a single Vinci rocket engine. Vinci is a new-generation cryogenic engine that can be reignited, allowing each launcher to reach multiple orbits in a single launch. The engine carries 31,000 kg of a LOX/LH2 fuel mix and runs on an expander cycle. The expanding hydrogen flow drives the propellant pump turbines, meaning the engine does not require a second combustion chamber as ULPM does. The Vinci Engine provides a vacuum thrust of 180 kN, with specific impulse of 457.2 s and combustion pressure of 60 bar. For its LOX-LH2 fuel mix, it has a mixing ratio of 6:1 with a propellant flow rate of 34.1 kg/s for LOX and 5.59 kg/s for LH2. Vinci has a turbopump head rotation speed of 90,000 rpm and a turbopump oxidiser rotation speed of 18,000 rpm. 9) 10) 14)

Launch Capabilities

Ariane-6 features an adaptable payload structure, allowing it to cater multiple mission types, including:

• Single launch
• Dual launch
• Multiple launch
• Large scientific spacecraft
• Heavy missions
• Constellations

The Ariane-6 fairing is 20 m tall, with an external diameter of 5.4 m, allowing it to launch any mission currently in service. The dual launch payload structure comes in three different lengths, 7.8 m, 8.8 m and 9.8 m, to meet different customer needs. The launch vehicle can also support missions of multiple small satellites, from cubesats to minisatellites up to 400 kg, and offers a rideshare service on both Ariane 62 and Ariane 64 launches that utilises spare capacity alongside primary missions. Additionally, Ariane-6 is capable of carrying heavy missions and large scientific spacecraft heavier than 20,000 kg with a single dedicated launch, and its dispenser structures can be modified to accommodate entire constellations of smallsats or microsatellites. 1) 10)

Mission Status

• July 9, 2024: Ariane-6’s maiden flight successfully launched from French Guiana at 16:00 local time. All phases of the launch were successfully enacted, resulting in the successful deployment of nine nine CubeSat rideshare payloads in a 600 km orbit. 2)

• October 10, 2020: The P120C booster underwent its final static fire test at the European spaceport in French Guiana. The test was the third such conducted, and resulted in the qualification of the design for the Ariane-6 rocket. 5) 8) 13)
• July, 2019: The Vulcain 2.1 engine has completed its qualification process with a final static firing test. The test lasted 11 minutes, with the engine running for 13,786 seconds over the course of the process. 7) 15)
• October 12, 2018: The final tests of the Vinci engine were carried out, completing its qualification process. This process entailed 148 tests in which the Vinci engine ran for 52,156 seconds. 14)

References

1) “Ariane 6.” Arianespace, URL: https://www.arianespace.com/vehicle/ariane-6/

2) “Ariane 6: post-launch update.” 31 July 2024, URL: https://www.esa.int/Enabling_Support/Space_Transportation/Ariane/Ariane_6_post-launch_update

3) “ArianeGroup explains how Ariane 6 rockets are built.” Ariane Group, URL:  https://www.ariane.group/en/news_kid/how-do-you-build-ariane-6-rockets/

4) ArianeSpace. “Ariane 6 User's Manual.” May 2016, URL: https://web.archive.org/web/20170214115631/http://www.arianespace.com/wp-content/uploads/2017/02/Ariane6_Users-Manual_February2017.pdf

5) Bergin, Chris. “Static Fire test for Europe's P120C rocket motor,” NASASpaceFlight.com, 16 July 2018, URL: https://www.nasaspaceflight.com/2018/07/static-fire-test-europes-p120c-rocket-motor/

6) “ESA - Ariane 6 overview.” European Space Agency, URL: https://www.esa.int/Enabling_Support/Space_Transportation/Launch_vehicles/Ariane_6_overview

7) “ESA - Vulcain 2.1.” European Space Agency, 24 October 2017, URL: https://www.esa.int/ESA_Multimedia/Images/2017/10/Vulcain_2.1

8) “Final hot firing proves P120C booster for Ariane 6.” European Space Agency, 8 October 2020, URL: https://www.esa.int/Enabling_Support/Space_Transportation/Ariane/Final_hot_firing_proves_P120C_booster_for_Ariane_6

9) “Gas Generator Cycle.” The Space Techie, 9 July 2021, URL: https://www.thespacetechie.com/gas-generator-cycle/

10) “In Depth - Ariane 62.” Arianespace, URL: https://www.arianespace.com/vehicle/ariane-6/in-depth-ariane-62/?stage=lowerstage

11) “Mission Profile - Ariane 62.” Arianespace, 15 June 2021, URL: https://www.arianespace.com/vehicle/ariane-6/mission-profile-ariane-62/

12) Rocket Science. “ESA-developed P120C solid rocket motor enters production.” 1 April 2022, URL: https://www.spacedaily.com/reports/ESA_developed_P120C_solid_rocket_motor_enters_production_999.html

13) “Successful first test firing for the P120C solid rocket motor for Ariane 6 and Vega-C - ArianeGroup.” Ariane Group, 16 July 2018, URL: https://www.ariane.group/en/news/successful-first-test-firing-for-the-p120c-solid-rocket-motor-for-ariane-6-and-vega-c/

14) “VINCI® ENGINE.” Ariane Group, URL: https://web.archive.org/web/20240718044120/https://www.ariane.group/wp-content/uploads/2020/06/VINCI_2020_04_DS_EN_Eng_Web.pdf 

15) “VULCAIN®2.1 ENGINE.” Ariane Group, URL: https://web.archive.org/web/20240726002959/https://www.ariane.group/wp-content/uploads/2020/06/VULCAIN2.1_2020_04_PS_EN_Web.pdf 

16) “The Vulcain 2.1 Engine: Powering Europe's Ariane 6 Rocket into the Future.” New Space Economy, 13 May 2024, URL: https://newspaceeconomy.ca/2024/05/13/the-vulcain-2-1-engine-powering-europes-ariane-6-rocket-into-the-future

17) “Flying first on Ariane 6,” ESA Ariane, URL: https://www.esa.int/Enabling_Support/Space_Transportation/Ariane/Flying_first_on_Ariane_6