Astronomical Optical Interferometry from the Lunar Surface

The lunar surface is a compelling location for large, distributed optical facilities, with signif-

icant advantages over orbital facilities for high spatial resolution astrophysics. The serious

development of mission concepts is timely because of the confluence of multiple compelling

factors. Lunar access technology is maturing rapidly, in the form of both US-based crewed and

uncrewed landers, as well as international efforts (Figure 1.1a). Associated with this has been

a definitive maturation of astronomical optical interferometry technologies at Earth-based fa-

cilities over the past three decades, enabling exquisitely sharp views on the universe previously

unattainable, though limited at present by the Earth’s atmosphere (Figure 1.1b). Importantly,

the increasing knowledge and experience base about lunar surface operations indicates it is

not just suitable, but highly attractive for lunar telescope arrays.

• Unprecedented Imaging Potential: Combining mature terrestrial optical interferometry

with emerging lunar surface technologies could enable optical imaging with far greater

resolution and sensitivity than current space or ground-based systems.

• Leveraging Existing NASA Funding: NASA Astrophysics and Planetary Science pro-

grams could fund lunar interferometry missions through existing competitive processes,

evaluated alongside orbital missions.

• Small-Scale Demonstration Opportunity: A near-term, small mission—such as an

Astrophysics Pioneers onboard a Commercial Lunar Payload System (CLPS) lander—

could demonstrate the feasibility and value of lunar-based interferometry.

• Medium-Class Mission for Advanced Techniques: A competitively selected medium-

class mission (e.g., via Small Explorer or Medium Explorer missions) could enable

precision interferometric methods like astrometry and nulling, supporting goals such as

exoplanet reconnaissance.

• Large-Scale Mission for Breakthrough Science: A Probe- or Flagship-class mission on

the Moon could deliver unprecedented sub-milliarcsecond imaging across UV to MIR

wavelengths, leveraging future lunar infrastructure for transformative astrophysics.