Lunar Interferometric Radio Array: A Telescope Concept Uniquely Enabled by the Lunar Far Side

Abstract

NASA'S plan to return to the moon by 2020 raises the possibility of conducting science specifically enabled by unique characteristics of the lunar surface. One such science objective is the study of the Epoch of Reionization in the formation of the universe, which has been given top priority by the 2001 National Research Council's Astronomy and Astrophysics Decadal Survey. The "Epoch of Reionization" is the period of transition of the universe from its early state of close-to-perfect uniformity to one of galaxies and inhomogeneous structures, and is currently an area where data is much needed. This period is best studied in the radio waveband, especially at low frequencies, which are inaccessible to ground observatories. In addition, these low frequency waves offer a window on the universe that is unexplored at present. This increases the potential for new and unexpected discoveries. The lunar far side provides an ideal radio-quiet environment essential to observe this period in the universe's history. Such an environment is unavailable on Earth or in near-Earth space. This paper presents the design of a lunar telescope facility that provides the capability to observe the "Epoch of Reionization" by placing a radio array on the far side of the moon. This array is envisioned to consist of 3440 simple radio dipoles, arranged in 215 clusters over an area 62 kilometers in radius, which provides a resolution of 12 arcminutes, to observe the Epoch of Reionization. Highlights of the design include a lightweight, self-deploying structure, a high data-rate wireless communication system, autonomous deployment, and high modularity of system elements. This project is designed to provide value to the exploration community in addition to the science community by leveraging planned lunar exploration architecture transportation elements, including the Ares V launcher, unmanned surface transportation rovers, and communications infrastructure. Additionally, the modularity of the design makes it highly robust from both a technical and a programmatic standpoint.