Wide Field-of-View Curved Focal Plane Array.

摘要

MIT Lincoln Laboratory has demonstrated the first digital, wide field-of-view (FOV), curved focal plane array. This unique device corrects for the inherent aberrations of mirrors and lenses in optical systems, and thus enables wide FOV surveillance of space. The curved focal plane was developed for the Defense Advanced Research Projects Agency's (DARPA) Space Surveillance Telescope (SST), a new, very wide FOV, ground-based, space surveillance system. The SST is a novel, three-mirror, Mersenne-Schmidt f/1 telescope design that retains its inherent field, or Petzval, curvature. This design choice produces a much larger FOV than the FOV of a conventional telescope while providing sufficient sensitivity to detect faint targets. The combination of wide FOV and sensitivity enabled by the curved focal plane array makes SST the nation's premier detector and tracker of objects in deep space. The SST's 3.5 m primary light-collecting aperture provides an order of magnitude improvement in detection sensitivity over current optics that employ flat charge-coupled devices (CCDs). DARPA initiated the SST program in 2002 to enhance the capabilities that could be offered to the U.S. Space Surveillance Network (SSN). The SSN is a worldwide network of radars and optical telescopes that provides tracking and custody of resident space objects. Ground-based optical telescope sites are the backbone of U.S. surveillance of so-called deep-space objects, i.e., those located out to altitudes of 36,000 km. What motivated interest in a more capable system was the advancement of satellite technologies into the microsatellite scale. Such payloads pose a collision danger to critical communication, military, and weather satellites, particularly in deep space. However, the SSN's assets have, until now, lacked the necessary sensitivity and FOV to detect and track very small objects in deep space.