The National Aeronautics and Space Administration (NASA, Washington, DC) and aerospace manufacturer BAE Systems (Rockville, MD) have developed a standard communications protocol for spacecraft electronics.
Called SpaceWire, the new standard is based on a communications protocol developed in 1999 by the European Space Agency. SpaceWire answers a long-standing spaceflight problem: No standard high-speed communications protocol existed for flight electronics. As a result, electronic equipment onboard spacecraft, such as processing units and computers, were custom-made on a project-by-project basis, resulting in long development times, high costs and elevated project risk.
SpaceWire was developed as a network of nodes and routers interconnected through bidirectional, high-speed serial links. The flexibility, modularity and reusability of SpaceWire will help limit the custom-design problem.
According to researchers at NASA's Goddard Space Flight Center, SpaceWire allows aerospace companies to standardize their designs. "SpaceWire lets you create one design that you can go to every time, for every mission," says the center's Glenn Rakow, lead developer for the SpaceWire project.
According to Rakow, the SpaceWire standard offers many advantages over other commercial protocols. "In a nutshell, it's flexible," explains Rakow.
For example, compared to Ethernet networks with preset link rates, SpaceWire offers flexible link rates, saving power and providing more options for high-speed applications. In addition, the standard is topology-independent, meaning that connections between routers or network fabrics can be fashioned in nearly any way that suits the design's needs. Finally, SpaceWire doesn't define a rigid data-packet structure. "It's very scaled down and simple, so it gives the system engineer a lot of flexibility in developing additional protocols," says Rakow.
While the standard is tailored to space-flight systems, the technology behind it may benefit ground applications as well. "SpaceWire technology development can be beneficial for wider U.S. industry and government use," explains Rakow. "The more people we get using it, the more ideas we'll have. Industry has expertise that NASA doesn't have and vice versa, and that exchange will benefit the SpaceWire standard."