John Aloysius O’Keefe, a man considered to be the father of space geodesy, a pioneer in planetary physics, and a longtime student of tektites, died in Sioux Falls, South Dakota, on 8 September 2000, of liver cancer complicated by Parkinson’s disease.
O’Keefe was born in Lynn, Massachusetts, on 13 October 1916. He graduated from Harvard University in 1937 with a bachelor’s degree in astronomy and received his PhD in astronomy from the University of Chicago in 1941. His first major discovery (in 1938) was that clouds of solid carbon cause the peculiar dips in the light curve of R Coronae Borealis, the archetype of a class of carbon-rich stars.
With the advent of World War II, O’Keefe was rejected for military service because of a physical disability. Instead, he joined the US Army Corps of Engineers as a civilian and began a new career as a geodesist, producing improved maps for the war effort. In 1945, the Army Map Service was formed to carry out the COE’s mapping and geodetic missions. That same year, O’Keefe was appointed to head the research and analysis branch, where he was responsible for geodetic R&D. During the 13 years he held this post, he not only made significant individual contributions to geodesy, but was a mentor who inspired his staff members.
As an astronomer, O’Keefe felt the lure of the space program. He left his position at the Army Map Service in 1958 to become the assistant chief of the theoretical division at NASA’s newly formed Goddard Space Flight Center in Greenbelt, Maryland, where he spent the rest of his career. Some of O’Keefe’s most influential early work at Goddard was behind the scenes. Eugene Shoemaker christened him “the godfather of astrogeology” for services on behalf of the Apollo program and especially for his key role in expanding the scope of the US Geological Survey to include other celestial bodies.
However, O’Keefe is probably best remembered for one of the very first scientific results of the space age. After analyzing the orbit of Vanguard I, only the second satellite launched by the US, O’Keefe and his coworkers announced in 1959 that Earth’s gravitational field perturbed the satellite’s trajectory beyond what was expected from a rotationally flattened planet; Earth showed a surprising lumpiness in the Southern Hemisphere. O’Keefe’s finding, dubbed the “pear-shaped Earth,” made the newspapers and even became the subject of one of Charles M. Schulz’s Peanuts comic strips.
In 1955, two years before Sputnik was created, O’Keefe proposed that geodesists track the motion of satellites for geodetic purposes. He intended to illuminate satellite-based retroreflectors with Earth-based searchlights. With the invention of the laser, optical tracking became feasible, and he strongly supported putting retroreflectors on satellites and on the lunar surface. At present, the LAGEOS (LAser GEOdynamic Satellites), STARLETTE, and similar retroreflector-bearing satellites measure plate motion, the Chandler wobble, and other geodynamic phenomena, and the retroreflector arrays the Apollo astronauts left on the Moon still bounce back laser beams shot from Earth. The lunar arrays have been used to test the theory of relativity.
During the last 30 or more years of his career, O’Keefe focused on the study of tektites, small glassy bodies of natural but unknown origin found in various “strewn fields” on Earth. In the 1950s and early 1960s, the leading theories were that tektites were of lunar origin, ejected by either impacts or volcanism, or they were formed by large asteroid impacts on Earth. O’Keefe published two books and many papers on the subject, and became convinced that tektites were ejected from volcanoes on the Moon.
However, since the late 1960s, scientists who have studied tektites have pointed to evidence that overwhelmingly suggests they were created as melt droplets from the impact of comets or small asteroids on Earth. O’Keefe’s decades-long advocacy for a lunar origin saddened and sometimes angered many of his colleagues in the tektite community. On the program at his funeral, his family had included the words “Tektitae de luna sunt,” which means “Tektites are from the Moon.
O’Keefe was endowed with a brilliant mind and a sharp wit. An innovative thinker, he possessed a contagious enthusiasm that often exceeded conventional bounds. He was a superb lecturer; his presentations frequently were flamboyant, giving rise to numerous amusing anecdotes among his associates. Above all, O’Keefe followed the dictates of his conscience in determining his actions. His colleagues remember him not only as an exceptional scientist, but as a remarkable person.
