Optical detection of rapidly moving objects in space

We compare the sensitivity of photon-counting and charged-coupled-device (CCD) imagers for rapidly moving objects. Our test case involves the detection of small objects in space, seen against a diffuse zodiacal light background, as observed from a space platform. We contrast photoncounting detectors, with excellent time resolution and negligible readout noise, against CCDs with a significantly larger quantum efficiency. For fast moving objects and small fields of view, the photon-counting detectors are able to detect significantly smaller targets, with the added benefit of providing angle-angle-time metric information in addition to high-time-resolution light curves. For larger fields of view and slower moving objects, the CCDs are more sensitive. These results may motivate the further development of microchannel-plate photon-counting systems and amplified CCDs for detecting and tracking space objects.