Not your Father's analog computer

WHEN NEIL ARMSTRONG and Buzz Aldrin landed on the moon in 1969 as part of the Apollo 11 mission, it was perhaps the greatest achievement in the history of engineering. Many people don't realize, though, that an important ingredient in the success of the Apollo missions and their predecessors were analog and hybrid (analog- digital) computers, which NASA used for simulations and in some cases even flight control. Indeed, many people today have never even heard of analog computers, believing that a computer is, by definition, a digital device.