The objective of the activity is to develop and test in orbit a very low latency satellite communication system at altitudes between 200km and 300km. This will include the design and manufacturing of a small payload. The activity will include six months of operations to characterise the orbital environment and test the functionality, versatility and performance of the communicationlink in this orbital range.
Targeted Improvements: Enabling satellite communication systems in 200 km to 300 km orbits for very lowlatency (less than 10 ms) applications.
The satellite communication market is changing rapidly, exploring non-GEO opportunities and concepts. One of the concepts currently pursued is large constellations in low Earth orbit, often targeting a significant reduction in size, power consumption and mass of a satellite, as well as reduced communications latency. For some user applications, such as financial services, low latency is crucial. A latency of less than 10 ms would make the perceived quality of a satellite service very similar or even better to the experience of terrestrial broadband communications. In addition, this would facilitatetheintegration with 5G networks.
A latency of less than 10 ms could be achieved by Very Low Earth Orbit (VLEO) satellite systems operating at an altitude in the range of 200 - 300 km. These systems also bring other important advantages, such as 10 dB lower pathloss and much smaller beam diameters projected on the ground. Together, these enable high frequency telecom payloads that are capable of supporting a data rate of several Gigabit per second, whilst consuming only a few Watts of power. This low power requirement opens up the possibility of reusing technologies currently under development for terrestrial 5G applications (e.g. SiGe chips for thebase station mMIMO antennas).
System studies have confirmed the potential of this concept and at least one commercial entity has submitteda frequency filing for a VLEO system. First experience with VLEO satellites was gained with the ESA GOCE mission, which operatedfor4 years at an altitude of 260 km. However, there remain many challenges in implementing a VLEO telecommunication system. They were not addressed in previous missions and cannot be fully addressed outside of the operational environment. For example, the impact of the high relative speed, as seen from the user terminal, induces high-rate frequency variations due to the Doppler effect. Furthermore, the environmental effect of atomic oxygen on the spacecraft and its antennas, as well as tropospheric propagation phenomena (e.g.effects of scintillation in a fast-changing geometry), are still not fully understood.
In order to fully characterise the orbital environment and test the functionality, versatility and performance of a low latency communication link in this orbital range,a smallflexible payload will be designed, manufactured and launched. It will be mainly based on commercial-off-the-shelf elements for the platform, including a software defined radio combined with a dedicated direct radiating array with agile beam forming capabilities. The payload will be integrated into a 6U Cubesat capable of six months (target) of in-orbit operations at an altitude of 200 300 km.