Wolfspeed of Raleigh, NC, USA, a Cree Company that supplies gallium nitride on silicon carbide (GaN-on-SiC) high-electron-mobility transistors (HEMTs) and monolithic microwave integrated circuits (MMICs), has partnered with security and aerospace company Lockheed Martin of of Bethesda, MD, USA to provide GaN high-power amplifiers (HPAs) for the US Air Force's Space Fence, which aims to significantly improve the timeliness with which operators can detect space events that could potentially threaten GPS satellites or the International Space Station.
Scheduled to go online from Kwajalein Atoll in the Marshall Islands in 2018, Space Fence will accurately track the estimated 500,000 objects — such as spent rocket boosters, stray hardware, and other debris — that are floating in the same space as the satellites on which modern technology depends. Developed by Lockheed Martin in partnership with Space Military Command and the US Air Force Life Cycle Management Center/Space Command Control and Surveillance Division, Space Fence incorporates a scalable, solid-state S-band radar with a high frequency that is capable of detecting much smaller objects than the current system, and should thus improve accuracy, quicken response time, and expand surveillance coverage.
Having completed the critical design review and begun construction, Lockheed Martin's Space Fence team is currently focused on the production of technology that will bring the system online, and has recently reached a major design milestone by confirming the long-term reliability of Wolfspeed's GaN HPA technology, which is integral to meeting the project's efficiency and availability requirements and will allow Space Fence to track 10 times more space junk than the current system. After more than 5000 hours (nearly seven months) of accelerated stress testing, Lockheed Martin has demonstrated greater than 99% confidence that Wolfspeed's GaN HPAs will meet the long-term reliability goals for the Space Fence program.
"These test results represent the culmination of more than a decade of shared investment in GaN technology," says Steve Bruce, vice president, Advanced Systems at Lockheed Martin Mission Systems and Training. "GaN HPAs provide significant advantages for active phased-array radar systems like Space Fence, including higher power density, greater efficiency, and improved reliability over previous technologies," he adds.
"Our high-performance commercial GaN products have been fielded for many years in a variety of military and commercial applications, and the successful completion of this most recent reliability milestone further validates that GaN technology has matured enough to support the mission-critical 24/7/365 coverage required by the Space Fence system," says Wolfspeed's RF and microwave director Jim Milligan.
