NASA-LMT: Orbital Object Detection via CCD Drift-Matching Mode            


A demonstration of the detection of an orbiting object via the drift-matching (DM) mode of CCD operation.

The CCD has been set such that its read direction and read rate exactly match the orbital parameters of a

catalogued object. In this example, the object is Satellite Number 14344 which is a piece of SL-8 debris with

a RCS derived diameter of 12.5 cm. When crossing through the LMT FOV, the object was at an altitude of

775 km with an angular velocity of 0.5833 degrees/sec, a position angle of motion of 74 degrees and a solar

phase angle of 68 degrees. The CCD was oriented accordingly and then read at the corresponding rate. The

object signal photons were then able to accumulate on only several pixels rather than streak through the FOV.

The vertical streaks are background stars which are virtually stationary at this high read rate and short effective

exposure time of 0.585 seconds. Based upon the measured net flux above background (1900 ADU) coupled with

the assumption of a 0.1 albedo and a specular phase function, the object optical cross-section (OCS) based diameter

is approximately 5.12 cm.  This white light image was acquired with the LSP 2K CCD with 16x16 binning in order

to accommodate the high angular rate and consequent short readout time.