Astraea (Ἀστραία) is from the Greek astron (star). As humanity's wickedness increased through the Silver, Bronze, and Iron ages, all the other gods abandoned the earth — Astraea was the last to leave, ascending to the heavens to become the constellation Virgo, holding the scales of justice (the adjacent constellation Libra). In Renaissance England, Queen Elizabeth I was hailed as Astraea returned — Edmund Spenser invoked her in The Faerie Queene.
Astraea does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Astraea reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.