Nanosatellites

6 I-2eCommunications

Nicolas Appel¹, Sebastian Rückerl¹, Martin Langer^1,2, and Rolf-Dieter Klein³

¹Institute of Astronautics, Technical University of Munich, Garching, Germany

²Orbital Oracle Technologies GmbH, Gilching, Germany

³Multimedia Studio Rolf-Dieter Klein, München, Germany

6.1 Introduction

The communication subsystems are among the most critical parts of satellites, as they provide the only access to the spacecraft. During the satellite's operations, the communication links are used for commanding, retrieving telemetry, tracking and ranging, and tasks such as applying software updates. Additionally, communication links relay and broadcast signals and downlinking payload data. The architecture of each communication link depends on its destined application. Figure 6.1 shows the two common types of nanosatellite communication links: space-to-ground links and intersatellite links. Space-to-ground communication is the default for virtually all communication services provided by satellites. Intersatellite links are an emerging technology among nanosatellites, as a means to coordinate and relay data within satellite swarms and constellations.

The space segment involved in both scenarios consists of a radio module and one or more antennas. The radio module is the active part of the space segment and provides the translation from digital baseband signals to high-frequency signals and vice versa. Most nanosatellite radio modules provide both receiver and transmitter functionalities ...