SBIR Company Advances Future Space Computers Published Dec. 12, 2006 By Plans and Programs Directorate AFRL/XP WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- Onboard computers are the primary means of operating satellites that cost millions of dollars to build and launch; once in orbit, however, these computers are not easily repaired if problems arise. Furthermore, space-deployed hardware cannot tolerate data errors, since ordinary microchip performance degrades considerably outside the earth's atmosphere. The traditional method of building spacecraft computers therefore involves the fabrication of very expensive, specialized chips, which result in slow, power-hungry processors. Consequently, the Air Force's Military Satellite Communications program tasked AFRL with finding innovative solutions to these challenges. Under an AFRL Small Business Innovation Research (SBIR) contract, Space Micro, Inc. (San Diego, California), developed a strategy for using commercial microprocessors in space. To address the issues surrounding a commercial microprocessor's usage in space, Space Micro focused on the dual problems of single-event upsets (a type of radiation-induced data error) and single-event functional interrupt hang-ups, both of which contribute to the unreliable performance of commercial chips exposed to high-energy cosmic radiation. To resolve initial difficulties, the company investigated a way to utilize existing circuitry to perform on-the-fly recalculation (and checking) of computations associated with critical operations. This straightforward approach beats the alternative of running three processors in parallel and voting their outputs. In addition, it uses less hardware and power, because the necessary level of redundancy is easily activated and deactivated as needed. Space Micro also incorporated a radiation-hardened watchdog chip, which triggers an automatic processor reset if it detects a hang-up in the apparatus. This innovative solution simplifies the architecture by eliminating the need to synchronize multiple processors. The company's final product consists of a high-performance, fault-tolerant computer--known as Proton--that employs low-cost, commercially available parts. To date, over 50 satellite programs have inquired about this commercially based, inexpensive, low-power approach to space computing systems, with nine various delivery contracts awarded from the Air Force, Missile Defense Agency, National Aeronautics and Space Administration, and Defense Advanced Research Projects Agency. Space Micro's groundbreaking prototype has thus established its legacy as one of AFRL's most successful SBIR effort