The Priced Ephemeris: Error Budgets of the Public Tracking Pipes and the Minimum Claim Each Can Honestly Carry

Every orbit-based claim rides on an ephemeris, and every ephemeris has a price: an error budget that decides the smallest claim it can honestly carry. This paper prices the four public tracking pipes the house programme will consume — TLE/SGP4, Conjunction Data Messages, satellite laser ranging, and Deep Space Network Doppler and ranging — in one common currency: delivered precision, error-growth behaviour, and minimum claim size under a stated carrying rule. The budgets differ by six orders of magnitude. A two-line element set carries a position claim no smaller than ~5 km at epoch and ~11–35 km after three days; a laser-ranged orbit carries one of ~10 cm; a DSN-tracked probe carries a line-of-sight velocity claim of ~0.5 mm/s and no useful claim at all about an Earth orbiter it never tracked. A worked example prices one hypothetical anomaly — a 2.50 km along-track displacement at two days — against every pipe with the arithmetic shown: killed by TLE/SGP4 at 0.5σ, not carried by CDM covariance at 1.7σ, carried by SLR at over 10⁵σ on its ranging component subject to a retroreflector condition, and carried in velocity by DSN if — and only if — the object is a DSN-tracked probe. The paper closes with the carrier table itself and the citation rule that goes with it: no house orbit-based claim ships without naming its pipe, its epoch distance, and its claim-to-error ratio.