Site selection for the Laser Interferometer Lunar Antenna (LILA)

Abstract

The Earth's Moon presents a uniquely advantageous environment for detecting astrophysical gravitational waves (GWs), particularly in the decihertz regime. The Laser Interferometer Lunar Antenna (LILA) project plans to perform GW measurements on the lunar surface, using the Moon's seismic quietness to access this band. Two mission concepts are considered: the proof-of-concept 1 km initial LILA (iLILA) and the full LILA Observatory, whose equilateral arms are at least 40 km long. The Moon's changing orientation and orbital motion provide the time-dependent source modulation needed for sky localization, so the detector response does not impose a unique lunar region. Practical considerations, most critically line of sight (LOS), nevertheless constrain deployment. A coarse-to-fine search of existing lunar datasets identifies and ranks candidate grid locations. Of 4,050 global grid seeds, 434 iLILA seeds and 71 Observatory circumcenters pass both search stages. These results demonstrate that sites suitable for GW detection naturally exist in large numbers on the lunar surface.