Hundreds of humans have orbited Earth since space exploration began more than half a century ago. In that time, astronauts have walked on the moon and even endured more than a year in microgravity.
But becoming a multiplanetary species — whether to flee a dying world or just explore the unknown — means learning to live without easy access to Earth’s resources and conditions.
The first space settlers will face some challenges as old as life itself, while other problems will rear their heads for the first time. Humans must solve them all if we want to survive beyond Earth’s warm embrace.
(Credit: NASA/KSC)
