C-0035 Under review MODERATE certainty
The onboard absolute-position fix the jump-navigation re-fix loop needs has flight heritage: NASA's SEXTANT experiment on the ISS demonstrated autonomous X-ray pulsar navigation 'better than 10 km, worst direction, onboard and in real-time' (November 2017, NICER instrument), with the stated goal of 10 km worst-direction using up to two weeks of dedicated millisecond-pulsar observations. This is the only flight-demonstrated, infrastructure-free absolute positioning technique in the corpus — it needs no ground link and no pre-placed beacons, which is what an interstellar re-fix requires. The regime gap is stated plainly: the demonstration is near-Earth (ISS orbital dynamics, Earth-vicinity pulsar geometry), and no source in the corpus prices XNAV accuracy at interstellar distances, where pulsar timing-model currency and signal-to-noise both degrade; a 2026 simulation study (not ingested) reports filter divergence after 20 days without timing-model updates even in cislunar-class scenarios. XNAV therefore enters the navigation architecture as the demonstrated fix mechanism whose interstellar error budget is an open line item, not as a solved component.
Standing peer reviewed contested · interpretation · TRL 2 Assumes SEXTANT/NICER ISS demonstration as reported in S-0028: MSP set led by PSR J0437-4715 class pulsars, two-week observation windows; 'infrastructure-free' means no ground segment during the fix itself; pulsar timing models still originate from ground radio campaigns Stops applying interstellar ranges and multi-year timing-model staleness — explicitly unpriced in the corpus; and any accuracy extrapolation beyond the demonstrated near-Earth regime Note PDB-41. S-0028 = AIAA SpaceOps 2018 proceedings (DOI 10.2514/6.2018-2538, resolved 1.000, CLEAN), fulltext from NTRS PDF (pdf-extract route; both quoted spans are prose, per the route's own rule). Companion paper AAS 18-155 (Mitchell et al., no DOI) deliberately not ingested — NTRS-only identifier, adds the same numbers.
What it rests on
E-0061 · S-0028 — SEXTANT X-ray Pulsar Navigation Demonstration: Additional On-Orbit Results · direct
…ted between November 10 th (DOY 314) through the 12th (DOY 316), met its primary goal by a chieving autonomous XNAV navigation performance better than 10 km, worst direction, onboard and in real-time. Mitchell et al. [8] provide a discussion the details of the flight experiment results, inc…
EXACT · re-found in source
E-0062 · S-0028 — SEXTANT X-ray Pulsar Navigation Demonstration: Additional On-Orbit Results · direct
… X-ray Pulsar Navigation (XNAV). The primary performance goal of the SEXTANT mission is to achieve real-time, onboard, navigation position accuracy of 10 km worst-direction, using up to two weeks of dedicated navigation-focused Millisecond Pulsar (MSP) observations. This uncertainty is calculated as < 17.3 km Root Sum Square (RSS) error compared to the on…
EXACT · re-found in source
Not yet challenged. A claim reaches "verified" only after surviving an attack.