Lunar Far-Side Radio Arrays: A Preliminary Site Survey

TL;DR

This paper conducts a preliminary survey of potential lunar far-side sites for a radio interferometer to study the Universe's Dark Ages, identifying three promising locations using high-resolution topographic data.

Contribution

It provides the first detailed site assessment for lunar far-side radio arrays using LRO LOLA data and introduces a figure of merit for site selection.

Findings

Three promising sites identified for lunar radio arrays.

High-resolution topographic maps were produced for potential sites.

Protection measures are recommended for these sites.

Abstract

The origin and evolution of structure in the Universe could be studied in the Dark Ages. The highly redshifted HI signal between 30 < z < 80 is the only observable signal from this era. Human radio interference and ionospheric effects limit Earth-based radio astronomy to frequencies > 30 MHz. To observe the low-frequency window with research from compact steep spectrum sources, pulsars, and solar activity, a 200 km baseline lunar far-side radio interferometer has been much discussed. This paper conducts a preliminary site survey of potential far-side craters, which are few in number on the mountainous lunar far-side. Based on LRO LOLA data, 200 m resolution topographic maps of eight far-side sites were produced, and slope and roughness maps were derived from them. A figure of merit was created to determine the optimum site. Three sites are identified as promising. There is a need to protect these sites for astronomy.