On-board switching and on-board processing for telecommunications satellites covers a wide range of capabilities, from a straightforward RF switch for carrier routing to selected downlink transmitter ports to the complex baseband switches with autonomous on-board control with direct user access.

In all countries visited, the panel found a hesitancy to commit to full OBS with autonomous on-board control. Most believe the costs and risks involved outweigh the benefits. However, thro ughout Europe and Japan there is a steady, evolutionary movement in this direction. The move to SCPC uplinks with TDMA downlinks with ground-controlled but on-board implementation of baseband switching of thousands of circuits is being implemented on sev eral experimental spacecraft.

Both the European and Japanese industries have demonstrated capabilities to design, develop, and manufacture equipment to accomplish state-of-the-art on-board processing and switching systems. Both have proceeded furth er in this direction than has the U.S. The launch of ACTS will demonstrate the primary U.S. commitment in this area. ACTS does rival European and Japanese capabilities. However, ACTS is a singular thrust where the European and Japanese have several pro grams: COMETS, ETS-VI, N-STAR, ITALSAT F1, ITALSAT F2, and ARTEMIS, to name the major efforts.

In summary, the state-of-the-art in manufacturing capabilities for on-board processing and switching appears to be about the same in the three industrial r egions discussed. However, the breadth of the European and Japanese efforts indicates that both are slightly ahead of the U.S. in this vital area and gaining.

Published: July 1993; WTEC Hyper- Librarian