<title>Microelectronics and photonics test bed dual-rate 1773 fiber optics data bus experiment</title>

Abstract

The dual-rate 1773 (DR1773) fiber optic data bus (FODB) experiment is one of twenty four space fight experiments on the Naval Research Laboratory's (NRL) microelectronics and photonics test bed (MPTB). MPTB is an NRL satellite payload that will be composed of modern technology microelectronics and photonic experiments. The Goddard Space Flight Center (GSFC) experiment on MPTB will evaluate the in-flight performance characteristics of the Society of Automotive Engineers (SAE) Aerospace Standard (AS) 1773 FODB in the space radiation environment. AS1773 is a passive star coupled FODB that operates at data rates of Mbps and 20 Mbps. This protocol is commonly referred to as 'dual-rate 1773 (DR1773).' Two different DR1773 fiber optic transceiver designs are tested on the experiment. These devices are the Boeing DR1773 and the SCI DR1773 transceiver. The transceiver devices on the experiment are implemented in a star coupled system and are tested at the higher 20 Mbps data rate. It is estimated that DR1773 at 20 Mbps will meet approximately 80% of NASA's current data rate requirements. DR1773's predecessor, Mil-Std-1773, is currently being flown on several NASA spacecraft. Mil-Std-1773 operates at a single rate of 1 Mbps. Because DR1773 is based on an existing bus protocol, incorporating DR 1773 into the NASA spacecraft program would be both time and cost effective. Success of the DR1773 experiment will provide valuable data on the DR1773 FODB space radiation performance as well as proof of concept for use of the DR1773 FODB for future NASA spacecraft systems.