When Neil Armstrong, Buzz Aldrin, and Michael Collins went to the moon 50 years ago this week, they had a large portion of the world’s computing power with them on Columbia and Eagle and behind them in Houston. One NASA engineer estimated that, between 1962 and 1967, the Apollo program had purchased 60 percent of all integrated circuits built in the US.
Today, however, that overwhelming proportion seems paltry in its aggregate power. The two Apollo Guidance Computers (AGC) onboard the spacecraft, for example, each contained 32 kilobits of random-access memory and 72 kilobytes of read-only memory. The AGCs had a primary clock running at 2.048 megahertz, and their 2,048 integrated circuits contained only several tens of thousands of transistors. They also weighed 70 pounds.
By comparison, today’s iPhone XS sports 32 gigabits of dynamic random-access memory, 256 gigabytes of storage, and a processor with 6.9 billion transistors running at 2.49 gigahertz. That’s a million times more memory, several million times more storage, and hundreds of millions times more processing power than the AGCs. All in a package one-hundredth the weight.
Even in the late 1960s, however, NASA had begun enjoying the early fruits of Moore’s law. As The Wall Street Journal noted in one of its many impressive articles on Apollo 11’s anniversary, “the first computer chips tested by MIT” — which built the AGCs — “cost $1,000 each. By the time astronauts landed on the moon, the price had dropped to $15 apiece. . . . It set a pattern of innovation, quality control and price-cutting that persists in the computer business to this day.”
In another article about the software team, which had to do so much with such limited hardware, The Wall Street Journal described the tense moments just before landing on the moon, when the mission was nearly aborted:
Neil Armstrong hovered a few miles above the surface of the moon on July 20, 1969, searching for a safe place to make history.
Only minutes of fuel remained to land the first men on another world. A power meter failed in Apollo 11’s cramped lunar lander. Communications faded in and out. Then, warnings began flashing: Program alarm. Program alarm.
Five times the onboard computer signaled an emergency like none Armstrong and crewmate Buzz Aldrin had practiced.
In that moment, the lives of two astronauts, the efforts of more than 300,000 technicians, the labor of eight years at a cost of $25 billion, and the pride of a nation depended on a few lines of pioneering computer code.
Read the entire article and the related content. And of course watch last year’s feature film “First Man” and this year’s documentary “Apollo 11.” Looking back, Apollo 11’s skimpy digital capacity only amplifies the engineers’ creativity and genius and the astronauts’ bravery. With today’s technical capabilities and a little of their vision and determination, who knows what giant leaps are possible?
This item was originally published at AEIdeas.
