A World of Possibilities: introducing the Skyline S2 Laser Communication Terminal for HAPS platforms

In October of 2023, at the International Conference on Space Optical Systems and Applications (ICSOS), Remco van den Breeje presented the Skyline S2 Laser Communication Terminal (LCT) to the world for the first time along with a paper on the development of the product. Skyline S2- a collaborative development by Airbus NL, VDL and TNO for AALTO’s High-Altitude Pseudo-Satellite (HAPS), called Zephyr- will deliver a robust and secure connection in a compact form, ideal for communication in industries and communities focussing on topics varying from disasters response to scientific research. Skyline S2 is part of Airbus Netherlands’ laser communication activities.

A world of possibilities

The Skyline S2 LCT will enable a 1 Gbit/s inter-Zephyr bi-directional link, spanning distances of up to 100 km. The design is a novel compact 40 mm aperture LCT and it is the first to meet the requirements concerning mass, size and power consumption that come with flying on a light-weight HAPS. As such, it will revolutionize connectivity: a network of Zephyrs with Skyline S2 LCTs could provide on-demand coverage in remote or disaster-stricken areas where regular communication infrastructure is lacking or disrupted. Moreover, HAPS platforms can be used to fill in gaps in satellite communications coverage to ensure 24/7 connectivity when needed. 

Tackling a broad range of challenges

The paper presented at the ICSOS focuses on the early stages of development in which a number of technological challenges had to be tackled while designing the LCT. These range from pointing and acquisition challenges and size, weight and power restrictions on a HAPS, to the stratospheric environment, where temperatures can range from -40 to -80 degrees Celsius. Furthermore, the paper shows the lab tests done in parallel that provided useful input to the design process. The results of these tests are also what ultimately supported the decision to announce Skyline S2 to all, because they confirmed that a smart configuration of laser communication technology on an innovative Zephyr platform could open up all kinds of possibilities in the world of connectivity.

Skyline S2 lab test setup

What is next

Once funding is secured, the next step is to take verified and qualified Skyline S2 LCTs on two Zephyr to the sky and perform inter-flight trials. These trials may potentially lead to extending the 100 km distance and the data transfer rate between Zephyr platforms. Looking ahead, we envision a network of inter-connected Zephyrs and interoperability with other platforms, including Low Earth Orbit (LEO) satellites.