The Dark Ages Radio Explorer (DARE) is a proposed NASA mission aimed at detecting redshifted line emissions from the earliest neutral hydrogen atoms, formed post-Cosmic Dawn.
Emissions from these neutral hydrogen atoms, characterized by a rest wavelength of 21 cm and a frequency of 1420 MHz, offer insights into the formation of the universe's first stars and the epoch succeeding the cosmic Dark Ages.
Around 400,000 years post-Big Bang, at a redshift of approximately 1100, the cooling of primordial plasma allowed protons and electrons to merge into neutral hydrogen atoms, rendering the universe transparent as photons ceased to interact significantly with matter.
Theoretical models forecast that, over subsequent hundreds of millions of years, gravitational forces gradually compressed the gas into denser regions, culminating in the emergence of the first stars—a milestone known as Cosmic Dawn.
While theoretical models indicate that current measurements are starting to examine the concluding phase of Reionization, the initial stars and galaxies from the Dark Ages and Cosmic Dawn remain beyond the observational reach of contemporary instruments.
[4] The envisioned DARE mission aims to conduct pioneering measurements of the inception of the first stars and black holes, as well as ascertain the characteristics of hitherto undetectable stellar populations.
DARE’s tentative schedule involves a 3-year lunar orbit, focusing on data collection above the Moon’s far side—a region considered devoid of human-made radio frequency interference and substantial ionospheric activity.
The mission’s scientific apparatus, affixed to an RF-quiet spacecraft bus, comprises a three-part radiometer system featuring an electrically short, tapered, biconical dipole antenna, along with a receiver and a digital spectrometer.