J. T. Armstrong (Naval Research Laboratory), R. B. Hindsley (Naval Research Laboratory), S. R. Restaino (Naval Research Laboratory), J. A. Benson (U. S. Naval Observatory), D. J. Hutter (U. S. Naval Observatory), F. J. Vrba (U. S. Naval Observatory), R. T. Zavala (U. S. Naval Observatory), S. A. Gregory (Boeing LTS, Inc.), H. R. Schmitt (Interferometrics, Inc.)
Keywords: Instrumentation, Sensors & Systems
Abstract:
We report the interferometric detection of an earth-orbiting artificial satellite using optical interferometry. We targeted four geosynchronous communications satellites with the Navy Prototype Optical Interferometer (NPOI) near Flagstaff, AZ, and obtained interferometric fringes on one of them, DIRECTV-9S. We used an east-west 15.9-meter baseline of the NPOI and took data in 16 spectral channels covering the 500-850 nm wavelength range. Observations took place during the “glint season” of 28 February to 3 March 2008 and then again from 26 February to 4 March 2009, when the geometry of the solar panel arrays and the Sun’s position creates glints as bright as 2nd magnitude for a few minutes each night. Subsequent analysis shows that the fringe amplitudes are consistent with a size scale of the glinting area of less than 2 meters (50 nanoradians at GEO) in an east-west direction. This work shows that interferometric detection of satellites at visual wavelengths is possible, and suggests that a multi-baseline interferometer array tailored to the angular size and brightness of geosynchronous satellites could lead to images of these satellites.
Date of Conference: September 1-4. 2009
Track: Instrumentation, Sensors & Systems