Providing ultra-high accuracy automatic ground test equipment to monitor the integrity and performance of the Ariane 6 fiber optic control system network
In 2014 the Ariane 6 development program was launched in response to SpaceX’s aggressive commercial strategy with the objective for the European Space Agency to maintain a leadership position that was suddenly challenged. A cost saving target of 50% on every flight compared to Ariane 5 was set for Ariane 6. This should be achieved thanks to a restructured organization and several key innovations. One of the important technical innovations is the use of opto-pyrotechnics for the control of key phases of the launch.
IDQ has been involved in the program since 2017 to develop custom and high performance ground test equipment capable to perform integrity and performance monitoring of the entire fiber optic network of Ariane 6 control system’s associated with the opto-pyrotechnic system.
The pyrotechnic control system onboard Ariane 6 is a technological breakthrough. The unique all-optical fiber-optic based opto-pyrotechnic control and command system provides higher performance and significant cost-savings.
In space, pyrotechnic techniques are utilized in both launchers and satellites and are traditionally based on electro-pyrotechnic devices with primary explosives. Such devices are used to trigger the different phases of a flight, from ignition to booster and stage separation, and all the way to passivation and even mission neutralization.
The all optical opto-pyrotechnic system onboard Ariane 6 offers significant cost reductions in terms of integration and procurement as well as a safer working environment on the assembly sites and launch pad. It uses high-power laser diodes connected to low-energy optical detonators via a fiber optic network. The devices are also relatively simple, very light, and compact, thus saving significant weight and costs, whilst providing highly reliable near-instantaneous response with very little input energy. It is the first time opto-pyrotechnics has been successfully integrated and used on a European space launcher.
Fiber optics brings other important advantages. Optical fibers can be easily tested, e.g. their transmission performance can be accurately measured. And, they are totally immune to electro-magnetic perturbations.
One of the challenges encountered on Ariane 5 and previous programs is that the use of conventional electro-pyrotechnics requires very strict and complex safety measures, making the launcher assembly and testing phases hazardous, lengthy and eventually very costly. The immunity of optical fibers to electro-magnetic perturbations greatly reduces the incident risk level, with fewer constraints regarding the access to sites.
Optical time domain reflectometry (OTDR) is an attractive technique for such test & measurement, as it provides integrity information, and insertion and back-reflection loss profiles, with high spatial resolution and event/failure localization.
Advantages of opto-pyro technique
- Reduced acquisition cost (fiber optic cables versus copper wires)
- Reduced total mass and volume
- Simple to handle and faster to install
- Immunity to electromagnetic interference (EMI and ESD)
- Safer, non hazardous testing possibilities
But the measurement performance requirements imposed by the opto-pyro application are impossible to meet with conventional OTDR systems: centimeter scale spatial resolution, presence of multiple lossy connectors, free space optical safety barrier, quasi real-time measurement and strict limitation on laser power due to optical detonators at the end of each line. Sensitivity requirements are about two orders of magnitude higher than what commercially available OTDR systems can achieve.
And this is where IDQ got involved.
The solution: Ultra-high resolution and autonomous OTDR-based integrity monitoring system
Since its inception ID Quantique has been involved in the development and application of single-photon detection and photon counting technologies and applications. Thanks to this unique expertise and know-how, ID Quantique was contracted by ArianeGroup in 2017 to develop a custom and dedicated ground test equipment for integrity and performance monitoring of the Ariane 6 fiber optic control system network based on a photon counting OTDR technique, the only option meeting ESA high performance requirements.
For this project, IDQ teams used the IDQ’s ID281 SNSPD (Superconducting Nanowire Single-photon Detector) as the foundation of the photon-counting OTDR system. The technology of IDQ’s Time Contoller Series electronics and Picosecond Pulsed Laser source were integrated in the system to achieve the required sensitivity and spatial resolution together with a multiple channel switch to automatically scan all the channels of the complex opto-pyro fiber optic network in a few seconds per channel. Control and analytical software was specially developed to both control the measurement and perform an analysis of the recorded back-scattered profiles with respect to preset channel configuration including, attenuation thresholds by segment and back-reflection. The software allows automatic detection and localization of any abnormal loss, fiber attenuation or back-reflection documented in an automatically generated test report.
A complete multi-channel turnkey solution with control software
| Ultra-fast semiconductor pulsed laser |
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| ID281 Superconducting Nanowire Single-Photon detection (SNSPD) |
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| Photon counting and timing electronics |
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| Dedicated control software |
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The turn-key solution guarantees:
- End-to-end validation of the entire optical pyro-lines
- Quasi real-time measurement
- Automatic testing and performance analysis with no human intervention
- Ultra-high resolution (centimeter scale spatial resolution) and unrivalled dynamic range (>70 dB)
- Completely safe operation (zero risk with optical detonators)
- Real-time identification of integrity problems and system performance
- Fully compliant with drastic launch pad safety requirements
What were the requirements?
A turnkey solution with a measurement accuracy unachievable by traditional means (centimeter spatial resolution), integrating ultra fast detection of integrity issues. The monitoring solution needed to be designed for automated tests with minimum to no human intervention and to provide automatically generated test report (pass/fail) with problem identification and localization.
What are the advantages of Single-photon technologies?
Single-photon detection, and here more specifically SNSPD, is the essential enabling technology for such high-performance OTDR as it provides the ultimate light detection sensitivity, high timing accuracy, short dead time, and a high dynamic range.
Where is the solution used?
The IDQ ground test equipment is used in Kourou as well as in the different Ariane 6 assembly sites in Europe.
Successful first launch of Ariane 6 on July 9th 2024
Ariane 6 completed its first flight, from the Guiana space center. A huge success for the European space sector. ID Quantique is very proud to be a part of this revolutionary project, which marks the first full industrial application of IDQ’s SNSPDs.
