  We have conducted a detailed simulation of LSST's ability to link near-Earth
and main belt asteroid detections into orbits. The key elements of the study
were a high-fidelity detection model and the presence of false detections in
the form of both statistical noise and difference image artifacts. We employed
the Moving Object Processing System (MOPS) to generate tracklets, tracks and
orbits with a realistic detection density for one month of the LSST survey. The
main goals of the study were to understand whether a) the linking of Near-Earth
Objects (NEOs) into orbits can succeed in a realistic survey, b) the number of
false tracks and orbits will be manageable, and c) the accuracy of linked
orbits would be sufficient for automated processing of discoveries and
attributions. We found that the overall density of asteroids was more than 5000
per LSST field near opposition on the ecliptic, plus up to 3000 false
detections per field in good seeing. We achieved 93.6% NEO linking efficiency
for H<22 on tracks composed of tracklets from at least three distinct nights
within a 12-day interval. The derived NEO catalog was comprised of 96% correct
linkages. Less than 0.1% of orbits included false detections, and the remainder
of false linkages stemmed from main belt confusion, which was an artifact of
the short time span of the simulation. The MOPS linking efficiency can be
improved by refined attribution of detections to known objects and by improved
tuning of the internal kd-tree linking algorithms.
