About NavLunar
The map comes before the ship. When Artemis astronauts report a position on the lunar surface, they won't read out latitude and longitude. They'll use the Lunar Grid Reference System (LGRS), an MGRS-style grid published by USGS and NASA in 2024 and 2025. NavLunar is a civilian reference instrument for that grid: the first public interactive viewer of the LGRS, with a permanent, linkable URL for every 25-km cell and every named feature, so anyone can point at a place on the Moon the way they share a map pin on Earth.
NavLunar is built entirely on open NASA, USGS, and IAU data. It is not affiliated with NASA or USGS. It sells nothing and claims nothing: this site does not sell lunar land, does not imply ownership of any part of the Moon, and never will. No one owns the Moon; under the Outer Space Treaty of 1967, no one can. This is a map, not a deed office.
Data sources
Full provenance (exact URLs, retrieval dates, verification steps) is recorded in the repository's DATA_SOURCES.md.
Methodology
Reference frame & projections. All coordinates are selenographic (planetocentric, east-positive) on the 1,737,400 m lunar sphere in the JPL DE421 mean-Earth frame, the same frame as LRO data products. Between 80°S and 80°N the grid uses the Lunar Transverse Mercator projection (45 zones of 8° per hemisphere, k₀ = 0.999, false easting 250 km); poleward of ±80° it uses Lunar Polar Stereographic (k₀ = 0.994, false origin 500 km), per USGS TM 11-E1.
Verification. Our TypeScript grid engine is validated by 1,300+ unit tests, including ~1,700 ground-truth conversions generated by executing the USGS reference implementation, all documented worked examples from the USGS/NASA publications, and round-trip property tests across zones, hemispheres, and the polar boundary. Where the specification is ambiguous at exact cell boundaries, we pin a deterministic convention (a boundary belongs to its north/east cell) and document every deviation in the repository.
Live terminator. The day/night line is computed from the Sun's direction in the Moon's body-fixed frame (IAU WGCCRE 2015 rotation model via astronomy-engine), refreshed every minute, and sanity-tested against known full and new moon dates and the ~12.2°/day terminator advance.
Known limitations (v1). The map is equirectangular, so polar cells appear stretched; a dedicated polar stereographic view is planned. Grid math uses the reference sphere; terrain-induced distortion factors (USGS raster products) are not yet applied. ACC 6-character codes are 10-m references within a named 25-km cell, per the LGRS overview. Feature pages show gazetteer center points, not outlines.
Questions or corrections? Every number on this site traces to a source. If you find one that doesn't, it's a bug.