THOR (Tracklet-less Heliocentric Orbit Recovery) links astronomical detections across multiple epochs to identify observations belonging to the same moving Solar System object. The software searches detection catalogs by testing heliocentric orbit hypotheses and associating observations consistent with each candidate orbit. This approach enables recovery of asteroids and other moving objects without requiring intranight tracklets or a predefined observing cadence. THOR can therefore analyze survey data sets with irregular temporal sampling and link observations separated by days to months. The code supports large-scale processing of survey catalogs to aid discovery and orbit determination of asteroids and other minor bodies.