The Dark Ages Radio Explorer (DARE) is a proposed moon-orbiting radio probe that would seek to answer many questions about the early universe: When did the first stars light up? What kind of stars were they? When were the first black holes created? How massive were these black holes? How did the first galaxies start to form? When did the universe transform from opaque to transparent?
As the universe cooled and expanded, particles were able to combine to form neutral atoms. Space became filled with dense, neutral hydrogen gas, through which light could not pass.
As the first stars ignited, their energy reionized the hydrogen gas. Bubbles of transparency began to form in the opaque universe, and radiation began to travel freely.
DARE's instruments would study the frequency of radio waves emitted by hydrogen atoms in the early universe. The spacecraft's radial antennas span 24.6 feet (7.5 meters) when fully extended. The probe weighs 2,640 lbs. (1,198 kilograms) when fully fueled.
DARE's 2-hour science orbit would make use of the moon to shield the probe from the heat of the sun and the radio noise from the Earth. Around the time of a full moon, DARE is doubly shielded and can make optimal observations.