Lunar far side is shielded from the Earth-based radio frequency interference (RFI) and is a promising site for precision radio astronomical observations even from an orbit above the Moon. The Dark Ages Radio Explorer (DARE) is designed to measure the all sky-averaged HI 21-cm signal from the Dark Ages and Epoch of Reionization from the Moon. DARE will orbit the Moon for a mission lifetime of ≤ 3 years and only take data above the lunar far side. DARE comprises of a single radiometer operating between 40-120 MHz (redshifts z=11–35). The science objectives of DARE include formation of first stars, first accreting black holes, beginning of reionization and end of the Dark Ages. The science instrument is composed of a three-element radiometer, including electrically-short, tapered, bi-conical dipole antennas, a receiver, and a digital spectrometer. Although the TRL (Technology Readiness Level) of the individual components of DARE instrument is high, the overall instrument TRL is low. One of the main aim of the entire DARE team is to advance the instrument TRL. An engineering prototype is currently deployed near the future SKA-low site in Western Australia for an end-to-end validation of the instrument and our calibration techniques. This talk will focus the DARE mission concept and latest results from the observations with the DARE prototype. This talk will also outline a new calibration technique based on single load approach and a priori laboratory measurements of the instrumental response. The DARE prototype data from the ground shows effect of RFI (Radio Frequency Interference) and the Ionosphere, the two major challenges for a ground based DARE-like experiment.
This research has been supported by the Lunar University Network for Astrophysics Research (LUNAR), headquartered at the University of Colorado Boulder and funded by the NASA Lunar Science Institute via Cooperative Agreement NNA09DB30A. Part of this research was conducted at that the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.