Dark Ages Radio Explorer
Dark Ages Radio Explorer (DARE) is a NASA mission concept intended to identify redshifted line emission from the earliest neutral hydrogen atoms forming after the Cosmic Dawn. The emissions from neutral hydrogen atoms (which have a wavelength of 21 cm and a frequency of 1420 MHz at rest) provide unique opportunities to probe the formation of the first stars in the Universe and the period immediately following the Dark Ages of the universe. The planned orbiter would explore the universe as it was from around 80 million years to 420 million years after the Big Bang. The dataset gathered by the mission would provide insight about the formation of the first stars, how the first black holes grew so rapidly, and how the universe underwent reionization. Computer models of galaxy formation would also be tested.