Dwayne Day works in Washington where he leads studies on civil space and aeronautics programs. He also writes about the history of intelligence collection from space.

A few days after the Soviet launch of Sputnik in October 1957, William Guier and George Weiffenbach, a couple of wizards at the Johns Hopkins University Applied Physics Lab, tracked the satellite by listening in on its radio beeps. They knew from previous work tracking missiles launched over the ocean that by monitoring the frequency change as the satellite traveled — known as the Doppler shift — they could determine not only if it was advancing or receding from the receiving station, but also its position relative to the receiver.

Shortly after they demonstrated that capability, their boss called them into his office and told them to shut the door. He explained that if a person on the ground could determine the position of a satellite by precisely monitoring its frequency change, the opposite was true as well, and a satellite in a known orbit transmitting a radio signal could enable somebody on the ground, or at sea, to determine their own location with a high degree of precision: initially about 300 feet but eventually down to about 60 feet. That observation led to the Navy’s Transit navigation satellites, the first step toward the development a few decades later of the Global Positioning System, which helps guide your car with a precision of a few feet and enables surveyors with specialized GPS tools (and a little bit of patience) to map locations on Earth down to millimeters.

Such stories are the focus of Simon Winchester’s new book, “The Perfectionists: How Precision Engineers Created the Modern World.” Winchester examines how a desire for precision has driven technological progress and often been a prerequisite for it. The Applied Physics Lab at Johns Hopkins and the Transit satellites needed precision to a few hundred feet so that the Navy could target nuclear-tipped missiles. The military later needed GPS to provide greater location precision for conventional bombs. Surveyors desired exactitude as they carved up parcels of land. Photographers and scientists also sought greater precision in their devices. Precision emerges from both mathematics, which was essential for making Transit and GPS work, and materials — hard materials like metal and glass with predictable qualities.

Winchester approaches the subject in terms of degrees of precision, starting with the 10th-of-an-inch precision of a steam engine achieved in 1776 by Englishman John Wilkinson and proceeding to the incredibly fine tolerances required for the scientific device at the Laser Interferometer Gravitational-wave Observatory in Washington state, which was used in 2015 to successfully detect gravity waves. Along the way, he tells stories about finely balanced Rolls Royce engines, Leica cameras and their prized lenses, and the Hubble Space Telescope, whose mirror was carefully ground to exactly the wrong shape, “precisely imprecise,” as he puts it. Have no fear: It was later fixed and is widely regarded as one of the greatest scientific instruments ever created, becoming as universally known as Einstein and Shakespeare.


“The Perfectionists,” by Simon Winchester (Harper)

Winchester describes the smartphone as the most precise device that most people encounter in their everyday lives, and certainly the most common. This requires some qualification, however, because it is a precision electronic device, not a mechanical one; its parts all fit closely together, but they do not have to move. As Samsung recently discovered, precision can be problematic. The company packed everything in its Galaxy Note 7 phone so tightly that when the battery inevitably swelled a tiny amount, there was no room, and the highly charged device could burst into flames.

The book’s gimmick of ordering chapters by degrees of precision is actually quite logical, because precision is necessary to achieve precision. Developing nearly flawless optical surfaces or highly accurate timing devices requires machines and electronics that themselves have been refined to higher levels of precision over decades. Thus, a story of increases in precision is inherently chronological, although sometimes with many years between major advances.

But Winchester also warns that there is a cult of precision, a belief that incredible accuracy is inherently good, whereas good enough can often be acceptable and is almost always cheaper. Throughout the book he includes himself in the narrative, usually to tell stories of his encounters with precision devices and instruments over the years, starting as a kid in England in the 1950s, when his father showed him a collection of precisely machined metal objects used for calibrating tools. Another example is the time when, in his early 20s, he was working for an ocean surveying company for the petroleum industry and was responsible for precisely positioning a drilling rig on the floor of the English Channel. Using a radio beacon locating device, he gave the order to drop the legs of the massive machine and managed to set it down into the mud within 200 feet of an X on a map. He was informed that his very first drop was actually pretty good for a newcomer. But today it would be laughed at, and such rigs are regularly dropped to the ocean floor within a few centimeters of their mark. It probably makes little difference, he notes, but the cult of precision has driven the petroleum industry to this point.

There is no way for a story on this subject to be comprehensive, because precision has been a pursuit of so many areas of manufacturing, science and technology. Winchester therefore has had to be selective. He sagely notes that there is an aspect of this story that cannot be covered: the importance of precision for the development of top-secret intelligence collection equipment. For example, at the same time that Guier, Weiffenbach and others at the Applied Physics Lab were developing satellites to provide positioning information for the military, other scientists and engineers working at the Naval Research Laboratory in Washington were developing their own techniques for using satellites to locate radars and other emitting devices in the Soviet Union, or sorting through dense electromagnetic signal environments to capture the whispered radio emission from a Soviet intercontinental ballistic missile during its test flight.

It is difficult to see and comprehend immense precision, and sometimes that is because governments want it that way.

The Perfectionists
How Precision Engineers Created the Modern World

By Simon Winchester

Harper. 395 pp. $29.99