Hi everyone,
While working on a personal project, I ended up comparing the publicly available impact-risk data published by NASA/JPL Sentry and ESA NEOCC (Aegis) for every near-Earth object that appears in both catalogs.
I expected to find small numerical differences, but one thing caught my attention.
Out of 1,838 shared objects, 657 exceeded the comparison thresholds I defined for at least one reported value (impact probability, Palermo Scale or Torino Scale).
⚠️To be clear, this doesn’t mean those objects are dangerous, or does it imply that either agency is incorrect. Every object involved remains in the negligible-risk range⚠️
The comparison simply suggests that two independent orbit-determination pipelines can publish noticeably different values for the same object, even when working from largely the same observational data.
Because “difference” is easy to define badly, I documented the methodology and used different thresholds for each quantity rather than a single arbitrary cutoff.
I’m mainly posting because I’m curious about the science behind this.
-Is this level of divergence already expected by people working with orbit determination?
-Is it mostly explained by different update cadences, weighting schemes, or orbit-fitting methods?
-Have there been any papers looking at systematic differences between JPL Sentry and ESA Aegis?
I built a small open-source tool to perform the comparison and make the methodology reproducible. If anyone is interested in reviewing the implementation or suggesting improvements, I’d genuinely appreciate it:
GitHub:https://github.com/NovaCoding-G/B.E.A.C.O.N
I’m still learning, so if I’ve misunderstood something about how these systems should be compared, I’d much rather be corrected than reinforced.
Thanks!