April 12, 2011
Swirling thousands of miles above earth, military satellites provide critical capabilities to warfighters-which makes protecting them from collision with space debris, meteors and microsatellites a top priority. Until now, monitoring the deep regions of space has been difficult, with spots and gaps in coverage leaving these high-flying machines vulnerable. DARPA's newly developed Space Surveillance Telescope (SST) aims to change that, ushering in a new era of ground-based space surveillance technology to fill coverage gaps and offer an unprecedented wide-angle view of small objects in deep space.
"Currently we have a 'soda straw' view of deep space, where we can only see one narrow segment of space at a time," said Air Force Lt. Col. Travis Blake, DARPA's Space Surveillance Telescope program manager. "The Space Surveillance Telescope should give us a much wider 'windshield' view of deep space objects, significantly enhancing our space situational awareness."
The key to the SST is its innovative design, which allows the telescope to be much more compact than existing ground-based telescopes. Using a unique curved charge coupled device (CCD) technology, the SST doesn't require the long optics train of a more traditional telescope design. The design makes the SST less cumbersome on its moveable mount, enabling it to survey the sky rapidly. The telescope's mount uses advanced servo-control technology, making the SST one of the most agile telescopes of its size ever built.
"The SST will give us in a matter of nights the space surveillance data that current telescopes take weeks or months to provide," Blake added.
Beyond providing faster data collection, the SST is very sensitive to light, which allows it to see faint objects in deep space that currently are impossible to observe. The detection and tracking of faint objects requires a large aperture and fast optics. The SST uses a 3.5 meter primary mirror, which is large enough to achieve the desired sensitivity. The system is an f/1.0 optical design, with a large-area mosaic CCD camera constructed from the curved imagers and a high-speed shutter allowing for fast scanning at the high sensitivity.
The SST aims to provide a large expansion of the space objects catalog in the geosynchronous region of space, giving satellite operators a fuller picture of objects that could collide with satellites. In addition to detecting and tracking potential hazards in deep space, SST may also provide the science community a unique asset for astronomical surveys of stars and comets.
The SST achieved "first light," meaning the collection of its first images, earlier this year. DARPA's SST demonstration phase will continue to test and prove system functions and autonomous operations for detecting dim objects. DARPA's primary performers for the SST are the Massachusetts Institute of Technology's Lincoln Laboratories and L-3 Brashear Corporation.