MoonLITE: the Extreme Instrument for Extreme Solar Systems

The MoonLITE (Lunar InTerferometry Explorer) project is a 2023 NASA Astrophysics Pioneers proposal to develop, build, fly, and operate the first separated-aperture optical interferometer in space. MoonLITE is proposed fly as a payload hosted aboard one of NASA’s Commercial Lunar Payload Services (CLPS) landers, to deliver an optical interferometer to the lunar surface. Recent lunar surface operations by other telescope facilities have significantly retired the perceived risk of lunar dust contamination, and the stability of the moon’s surface markedly simplifies interferometer pointing and stationkeeping requirements relative to orbital concepts. The combination of high spatial resolution from optical interferometry, with deep sensitivity from the stability of the lunar surface, would open up unprecedented discovery space for exoplanet science. After landing on the lunar surface, the CLPS rover will deploy the pre-loaded MoonLITE outboard optical element 100 meters from the lander, establishing a interferometric observatory with a single deployment. MoonLITE combines a 110 microarcsecond limiting spatial resolution with enough sensitivity to observe targets fainter than 17th magnitude in the visible. The capabilities of MoonLITE open a unique discovery space that includes direct size measurements of the smallest, coolest stellar and substellar exoplanet hosts. MoonLITE will also conduct searches for close-in stellar companions orbiting exoplanet-hosting stars that could confound future HWO observations of Earth-like planets, as well as extragalactic science at extreme levels of angular resolution. MoonLITE will open up the lunar landscape for potential SMEX and MIDEX class facilities that will measure the masses of exoplanets via astrometric surveys. Twenty percent of the observing time of this revolutionary observatory will be also made available to the broader community via a guest observer program.