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Emerald: An Experimental Mission in Robust Distributed Space Systems

Distributed space systems are often cited as a means of enabling vast performance increases ranging from enhanced mission capabilities to radical reductions in operations cost. To explore this concept, Stanford University and Santa Clara University have initiated development of a simple, low cost, two-satellite mission known as Emerald. The Emerald mission has several on-orbit goals. First, it will verify an array of component-level technologies necessary for enabling highly capable and robust distributed space systems. Second, it will combine these technologies to experiment with simple closed loop relative positioning, distributed control, and autonomous operation. Third, it will validate the distributed space system concept by assessing how these capabilities improve a baseline scientific investigation involving lightning-induced atmospheric phenomena. The Emerald bus design is based on a heritage Stanford University design, a 15-kilogram, modular hexagonal vehicle relying heavily on commercial off-the-shelf components. Emerald is being funded through the AFOSR/DARPA University Nanosatellite Program, and a Space Shuttle launch in 2001 is being planned. This paper will discuss the Emerald team’s programmatic and on-orbit objectives, the conceptual design of the Emerald spacecraft, and the development approach adopted by the university team.