Photometric and spectral analysis of MPC object J002E3

Abstract

In September 2002, an amateur astronomer discovered a rapidly moving object that initially appeared to be a near-Earth asteroid. Analysis of the observations by the Minor Planet Center established that the object, identified as J002E3, was in a geocentric rather than heliocentric orbit. This extremely unusual orbit prompted a flurry of observational and analytic interest. Detailed analysis of incoming position observations at the JPL Near-Earth Object Program Office determined that the object was in an unstable, 42-day period orbit about the Earth. They concluded that this orbital behavior was inconsistent with a natural solar system body like an asteroid but was very consistent with a man-made body launched from the Earth. Their analysis of the orbital characteristics and the timeline pointed to the upper S-IVB stage of the Apollo 12 launch in November 1969. The measured spectra of J002E3 match white paint better than asteroid surface materials, and the measured photometric characteristics indicate that J002E3 does not appear to be an asteroid. The objective of this study is to determine if the observed lightcurves of J002E3 match those expected for a cylindrical rocket upper stage. The identification of J002E3 as an artificial satellite placed it within the research interests of the Air Force Research Laboratory Maui Optical and Supercomputing (AMOS) Site. The charter of this facility is the development and application of electro-optical imaging and non-imaging techniques for the identification of artificial, Earth-orbiting spacecraft. Photometric and high-resolution visible spectral observations of J002E3 were made using sensors on the 3.67-meter Advanced Electro-Optical System (AEOS) telescope and are in quantitative agreement with the astronomical observations. Detailed analyses of these observations were conducted with application of algorithms designed for use with artificial satellites. The configuration, size, and dynamics of J002E3 have been determined using photometric lightcurves. The high-resolution visible spectra are compared to the spectra of aged white paint observed on other rocket bodies. This paper presents the results of these analyses and compares them to results for artificial objects.