Feb 10 2010
Ball Aerospace & Technologies Corp. has successfully completed stray light testing of the Operational Land Imager (OLI) telescope assembly for NASA's Landsat Data Continuity Mission.
The first of its kind stray light test was conducted at Ball's new Stray Light Test Facility (SLTF) in Boulder, Colorado. The OLI instrument will provide 15-meter (49ft.) panchromatic and 30m multi-spectral earth-imaging spatial-resolution capability for the eighth mission in the Landsat satellite series. Control of stray light is critical to the quality of the OLI data product, requiring a level of testing no other earth remote sensing instrument of this caliber has undergone. The test included Point Source Rejection Ratio scans obtained over a wide range of angles and for four telescope configurations: open earth-view port, open and closed solar cal port and aperture shutter closed. Demonstrating sensitivity over 10 orders of magnitude, the quality and repeatability of the data proved that the OLI telescope has excellent margin on all on-orbit stray light requirements.
Ball's new SLTF is a Class 5 clean room designed to eliminate undesired sources of background light and to emphasize superior contamination control of the test environment. The double cylindrical chamber reflects the specular light away from the instrument under test. As the facility interior is nearly all black, illumination sources can be either a solar simulator or discrete laser wavelengths collimated into an 18-inch diameter beam. The facility is designed to test a wide variety of instruments up to approximately 2 meters per side and weighing up to 1,100 pounds over a wide range of elevation and azimuth angles.
"The universal value of the Landsat program is inestimable," said David L. Taylor, president and CEO of Ball Aerospace. "Testing of OLI in Ball's stray light facility brings us closer to delivering an instrument that will continue NASA's longest continuous imagery data record of our planet."
The Landsat program is a series of Earth-observing satellite missions jointly managed by NASA and the U.S. Geological Survey. For more than 36 years, Landsat satellites have continuously and consistently collected images of Earth, creating a historical archive unmatched in quality, detail, coverage and length. The Ball Aerospace OLI instrument, slated to launch in late 2012, includes a 185km swath allowing the entire globe to be imaged every 16 days. The multispectral imagery is gathered for applications that include agricultural monitoring, natural resource management, land-use planning and climate science.
Source: http://www.ballaerospace.com/page.jsp?page=1