Two hundred and twenty miles above Earth flies the International Space Station, a $70 billion1 engineering marvel that no onehas any idea what to do with. Short term, sure: astronauts, science, zero-gravity viral videos. Longer term, spending $3 billion to $4 billion annually to keep the ISS running conflicts with NASA’s other ambitions, like visiting Mars. Congress holds NASA’s purse strings, so ultimately the decision lies with that august body.