TDP1 Ground System Design

Abstract

This paper illustrates the historical development of the TDP-1 ground segment, the system as implemented and operational experience, as well as an outlook to future programs. Aim of the project TDP-1 – Technology Demonstration Payload No.1 - is the demonstration of a data relay service, using an optical High Data Rate Inter-Satellite Link (ISL) between a Laser Communication Terminal (LCT) flown on a low earth orbiting satellite (LEO-LCT) and a second LCT (GEO-LCT) placed on the geostationary communication satellite AlphaSat (of INMARSAT) . The LCT planning system consists of one geostationary satellite (GEO) and up to five low orbiting satellites (LEO) which are also referred to as customers. The main task of GEO within this system is to serve as service provider for the LEOs and one optional optical ground station (OGS). The service consists of an optical data link between the Laser Communication Terminals (LCT) of the satellites (inter-satellite-link,ISL) and a link from a satellite to a ground station (space-to-ground-link, SGL). DLR’s Operations Center (GSOC) role in the TDP-1 program includes design, development and integration of ground infrastructure and operations of the satellites and ground stations. GSOC already gained experience operating Laser Terminals in test scenarios on the TerraSAR spacecraft. This knowledge was be used to develop the TDP-1 operations concept. One major task is the planning of the laser connections and the required coordination between all parties. This paper will illustrate the development from the first activities at GSOC in connection with laser data transfer through the design of the TDP-1 system to an outlook at the EDRS operations concept.