Glenn Rakow, SpaceWire Development Lead, Goddard Space Flight Center

Glenn Rakow is the Development Lead for SpaceWire, a high-speed communications protocol for space-flight electronics originally developed in 1999 by the European Space Agency (ESA). Under Rakow’s leadership, the SpaceWire standard was developed into a network of nodes and routers interconnected through bi-directional, high-speed serial links, making the system more modular, flexible and reusable. In 2004 Rakow was named the recipient of Goddard’s James Kerley Award for his innovation and contributions to technology transfer.

NASA Tech Briefs: What is SpaceWire technology and how does it work?

Glenn Rakow: SpaceWire describes a spacecraft’s onboard data bus that was standardized by the European Space Agency under European Cooperation for Space Standardization. Basically, it’s a method for interconnecting spacecraft components similar to the way Ethernet hooks up computers in the office, except it’s optimized for the space environment. We care a lot about mass and power, so much so that we had to deviate from commercial standards to optimize it for those parameters. Not only power and weight, but we also want to optimize it for flexibility.

So again, it’s a European standard that we have been participating in the development of from the get-go, and it’s become kind of the de facto standard now, at least for high-speed data bus or networks for onboard spacecraft in the U.S., and it’s actually becoming the standard for ESA and the Russian Federal Space Agency, for which the acronym is ROSCOSMOS. They’re basically using it as well for most of their applications.

NTB: As you’ve noted SpaceWire was developed by the Europeans around 1999. How did you get involved with the technology?

Rakow: Actually I was involved with it back then as well. I was kind of independently looking at a previous IEEE standard, which was the precursor to SpaceWire called IEEE 1355. I had started looking at that back in 1998, but that standard had a lot of problems. It was basically not well defined and you couldn’t have given it to two independent people and developed a product that was compatible between those individuals. It had some inconsistencies and some vagueness that didn’t permit a solid design that could work with independent groups.

So basically I started working with that one and clarifying it while the Europeans were doing the same, and we had met and compared notes, and we basically had similar assumptions. I had a design based on my assumptions, and they had one, and there were some slight differences, so what I did was I adopted the differences in favor of ESA and we pretty much had SpaceWire from a very early stage. Before it was standardized we had a design that was up and running. We actually flew the first version of it on a mission called SWIFT, which is a gamma ray burst alert telescope. It catches gamma rays, which are very fleeting events, and quickly reports the detection of a gamma ray in less than a minute so that observers from around the world can quickly look up in the sky and see the gamma ray burst. So we flew the first version of it on SWIFT.

NTB: That was in 2004, correct?

Rakow: It was launched in 2004, but we actually developed it in 2000, 2001. The development cycles of these things are typically 3 or 4 years, so we had the development of it working well before 2004.

NTB: Is it currently being used on any other missions?

Rakow: That’s the only mission that’s currently on orbit from our side. We have boards and systems at the flight level for JWST – the James Webb Space Telescope. We’ve been developing the technology for that mission for years and we have prototypes and flight units working and integrated into the system. It’s to be launched in 2013. The technology is far enough advanced that we have flight units that have it in them.