Artemis will test communications between satellites and provide a practical demonstration of the reception of data from other satellites in orbit and their onward transmission to users in Europe. Satellites in low Earth orbit (LEO) that are used to gather information about the environment are restricted in their ability to communicate with the ground, but Artemis will make it possible to replay data from a LEO satellite to the same ground station in Europe while it flies over a large portion of the globe.

Artemis has a data-relay payload which comprises two complementary elements, both capable of providing direct communications between satellites in orbit. It can communicate with other spacecraft using either radio with a laser beam. The laser communications terminal, known as SILEX (Semiconductor Laser Inter-satellite Link Experiment), is a world first. Developed by ESA, this technology is of prime interest for future constellations of communications satellites in LEO that will need to communicate with each other. Laser beam communication offers very high data rates, less power consumption and interference, and lightweight terminals compared to conventional radio waves. The more advanced radio data-relay payload and laser data-relay SILEX payload carried by Artemis will build on this.

Artemis will carry a payload known as LLM (L-band Land Mobile) which will provide mobile communications services throughout western Europe and neighbouring regions, including the Mediterranean, the Middle East and parts of Russia. The LLM payload has four coverage beams, one that will extend over the entire area and three (known as spot beams) that focus on specific parts.  The versatility offered by the three spot beams will be further enhanced by the LLM’s capability to allocate bandwidth, power and frequencies across the four beams in response to changing communications demands.

One of the payloads on Artemis is designed to test satellite-based navigation technology and ultimately it is envisaged this will help in establishing a European system.