From a laboratory in Cambridge, a satellite the size of carry-on luggage is being prepared to answer one of astronomy's oldest silences: what happened in the universe's first billion years, before the first stars were born. CosmoCube will orbit the Moon's far side — the only place in the inner solar system shielded from Earth's relentless radio noise — and listen for hydrogen signals emitted 13.5 billion years ago, during the cosmic dark ages. It is a mission shaped by both scientific ambition and a quiet urgency, for the very silence that makes this observation possible may soon be lost to th