Decision tree depicting the selection of HEALPix order based on the minimum distance (d_min) of the SSO to the satellite (first decision level) and on the maximum distance (d_max) the SSO is expected to cover based on its theoretical proper motion (pm) during the time period sampled, where Δt = 10d (second decision level). Here, d_max is compared to the diameter size for each HEALPix order (D₁₂₈, D₆₄, D₃₂). An initial pre-selection process of ephemeris based on a CEU threshold of 1 deg is performed.