Wake Shielf Facility

Mission Profile

Wake Shield Facility (WSF) was a NASA-funded stainless steel disk measuring 3.7 meters in diameter, designed to fly as a free-flyer deployed from the Space Shuttle to grow ultra-pure semiconductor thin films in the ultra-high vacuum environment created in its wake. First flown in February 1994 aboard STS-60, WSF used the molecular flow shadow region behind the disk — where the density is a billion times lower than that achievable in ground-based labs — to deposit gallium arsenide and other compound semiconductor films with exceptional crystal quality. Three WSF missions demonstrated thin film growth rates superior to any ground laboratory, with potential applications in high-speed computing and telecommunications devices. The program pioneered commercial use of Shuttle free-flying attached payloads for materials processing.