A Radio Observatory on the Lunar Surface for Solar studies (ROLSS)

TL;DR

This paper proposes establishing a lunar surface radio observatory to image the solar wind at frequencies blocked by Earth's ionosphere, enabling advanced solar and heliospheric studies with high-resolution imaging.

Contribution

It introduces the concept of a lunar surface radio array for solar observations, detailing its potential design and scientific benefits over existing space-based and ground-based methods.

Findings

Lunar surface arrays can image radio emissions below Earth's ionospheric cutoff.

Such arrays enable high-resolution aperture synthesis imaging of the solar wind.

The proposed observatory could complement Solar Probe Plus observations.

Abstract

By volume, more than 99% of the solar system has not been imaged at radio frequencies. Almost all of this space (the solar wind) can be traversed by fast electrons producing radio emissions at frequencies lower than the terrestrial ionospheric cutoff, which prevents observation from the ground. To date, radio astronomy-capable space missions consist of one or a few satellites, typically far from each other, which measure total power from the radio sources, but cannot produce images with useful angular resolution. To produce such images, we require arrays of antennas distributed over many wavelengths (hundreds of meters to kilometers) to permit aperture synthesis imaging. Such arrays could be free-flying arrays of microsatellites or antennas laid out on the lunar surface. In this white paper, we present the lunar option. If such an array were in place by 2020, it would provide context for observations during Solar Probe Plus perihelion passes. Studies of the lunar ionosphere's density and time variability are also important goals. This white paper applies to the Solar and Heliospheric Physics study panel.