The Dark Ages Lunar Interferometer (DALI) and the Radio Observatory for Lunar Sortie Science (ROLSS)

Observations at radio wavelengths address key problems in astrophysics, astrobiology, and lunar structure including the first light in the Universe, the presence of magnetic fields around extrasolar planets, particle acceleration mechanisms, and the structure of the lunar ionosphere. Achieving the required performance demands observations at wavelengths longer than those that penetrate the Earth's ionosphere, observations in extremely "radio quiet” locations such as the Moon's far side, or both.

The Dark Ages Lunar Interferometer (DALI) is a Moon-based telescope concept, funded under the Astrophysics Strategic Mission Concept Study program, intended to observe the highly-redshifted hyperfine (21-cm) transition from neutral hydrogen (H I) in the intergalactic medium at z 30. This H I signal is potentially rich for both cosmology and astrophysics_for a portion of the Dark Ages, the physics is sufficiently simple that the H I signal can be used to constrain fundamental cosmological parameters in a manner similar to that of CMB observations, but the spectral nature of the signal allows the evolution of the Universe as a function of z to be followed. Observing at wavelengths around 5 m ( 60 MHz), DALI would be located on the Moon's far side, where it would be shielded from terrestrial emissions. We illustrate the notional DALI concept and identify required areas of technology development.

The Radio Observatory for Lunar Sortie Science (ROLSS), funded under the Lunar Sortie Science Opportunity program, is intended to probe particle acceleration in the inner heliosphere and the lunar ionosphere. ROLSS is designed to be deployed during the first lunar sorties (or even before via robotic rovers), and would also serve as a pathfinder for a future larger telescope, such as DALI. We describe the science antenna design work, antenna materials testing, and a system-level analysis.