In May 1961, weeks after Gagarin's flight, President John F. Kennedy declared that the US would land a man on the Moon before the decade's end. It was an extraordinary gamble. The US had barely managed a 15-minute suborbital flight. The technology to reach the Moon did not exist yet. NASA had to invent nearly everything from scratch.

The Apollo program consumed about 4% of the federal budget at its peak — roughly $200 billion in today's money. It employed 400,000 people and involved 20,000 companies. The Saturn V rocket, for decades the most powerful rocket ever flown, generated about 7.6 million pounds of thrust at liftoff.