John Call Cook (April 7, 1918 – October 12, 2012) was an American geophysicist who played a significant role in establishing the field of ground-penetrating radar. He is widely recognized for contributing fundamental research that advanced its development. Cook also demonstrated that aerial surveys could map surface radioactivity, enabling more efficient prospecting for uranium ore. He invented electrostatic detection methods for identifying hazardous ice crevasses and developed additional techniques in remote sensing. For most of his professional career, Cook specialized in remote sensing and the detection of underground objects.
Early years John Call Cook was born on April 7, 1918, in Afton, Wyoming, to Carl and Ella Cook. His father worked as an attorney and farmer, and was the son of Phineas Wolcott Cook and his fourth wife, Johanna. As a teenager, Cook constructed a number of devices, including a spark-gap transmitter, a batteryless crystal radio, a six-inch telescope, and an improvised diving helmet made from a cookie can with a bolted plastic sheet for vision. The helmet was supplied with air through a garden hose powered by three tire pumps connected together.
University
Undergraduate Cook first studied at Brigham Young University before transferring to the University of Utah to study physics. In the spring of 1941, he began working as a laboratory assistant at the university and graduated later that year.
The war years As a physics major during World War II, Cook was recruited to work at the Radiation Laboratory at MIT, where he was assigned to the "Experimental Systems Group – 44" under Dr. James L. Lawson in the Roof Laboratory. The group focused on advanced radar problems, including signal discernibility, anti-jamming methods, short pulses, and receiver design. Its experimental systems frequently set performance standards, with members continually expanding the range of radar capabilities. They employed S-band (10 cm wavelength) and X-band (3 cm) radar sets, each with several types of display, and later obtained a K-band set (1 cm), which was capable of resolving the structure of nearby objects such as a gasholder. Each set contained about 300 vacuum tubes, 10 to 20 adjustment knobs, and numerous interconnecting cables. Vacuum tube failures occurred nearly every day, requiring extensive troubleshooting. The group often tracked a B-17 bomber sent from Bedford Airfield, experimenting with frequency and polarization, the use of chaff, jamming countermeasures, and evaluating whether propeller modulation of signal amplitude could distinguish friendly from hostile aircraft.
MIT Rocket Research Society Cook was elected president of the Rocket Research Society, a special-interest club at the Radiation Laboratory. Although the American Rocket Society in New York had suspended activities during the war, the MIT group continued experimenting with liquid-propellant rockets. Cook built a portable test stand from a wooden box, which included a thrust gauge, fuel and oxidizer tanks, valves with long control rods, and an electric ignition system. Together with Bob Smith and other members, he built rocket motors from materials such as steel, aluminum, ceramics, and even silver coins, using the lathes and facilities of the MIT Student Model Shop. Members obtained liquid oxygen from the nearby Arthur D. Little Company, which was developing a portable military LOX generator and discarding excess product. The group transported the liquid oxygen in five-gallon steel cans insulated with fiber mat. In one of their most successful tests, a rocket motor produced a ten-foot flame with standing shock waves, driving the thrust gauge off-scale for more than ten seconds. However, the aluminum motor burned out and ignited the test stand, which they extinguished with a Pyrene fire extinguisher. The carbon tetrachloride extinguishing agent produced phosgene and chlorine gases, which corroded the metal equipment. With liquid oxygen still remaining, the group conducted a controlled explosion. The blast propelled a wooden board 50 feet into the air and embedded gravel in the chest of the person lighting the fuse, despite Cook's safety precautions. The incident was later exaggerated in MIT's humor magazine Voo Doo, which portrayed Cook as the nonchalant "Lon Crook". In spring 1945, news arrived of German V-2 missile attacks on Britain. The German Rocket Society, supported by the government, had advanced far beyond American efforts, continuing the work of Robert Goddard. Their large rockets were used for military purposes, which Cook found disheartening. He subsequently lost interest in rocketry until the creation of NASA. Anticipating his departure from Cambridge, he resigned as president of the MIT Rocket Research Society and was succeeded by Robert Kraichnan, who later became prominent in the study of general relativity.
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