Ruoyan Zhao is an MPhil candidate in Mechanical Engineering at UNSW, currently developing reduced-order thermospheric density models to improve prediction of LEO object reentry trajectory and lifetime. The ongoing work integrates Starlink ephemeris data with an Unscented Kalman Filter, comparing linear (POD + DMDc) and nonlinear (Diffusion Map + m-PCE) models based on JB2008, NRLMSIS 2.1, and DTM2020 for faster, more accurate satellite-tracking and space-traffic management.