George R. Carruthers

• Born: October 1, 1939
• Birthplace: Cincinnati, Ohio
• Died: December 26, 2020
• Place of death: Washington, DC

American astrophysicist

George R. Carruthers designed and built the first space-borne ultraviolet light detector and camera and made the first measurements of ultraviolet emission from sources beyond Earth.

Primary fields: Aeronautics and aerospace technology; physics

Primary invention: Far-Ultraviolet Camera

Early Life

George Robert Carruthers was born to Sophia and George Carruthers on October 1, 1939, in Cincinnati, Ohio. His father was a civil engineer with an interest in astronomy. Young George received most of his primary education in the town of Milford, Ohio, where the family moved when he was seven. He grew up in the exciting first years of space exploration, when the idea of space travel was fanned by science-fiction books and films. His father encouraged him to learn about science and technology and fostered his son’s interest in model rockets and astronomy. The boy built his first telescope at the age of ten.

Two years later, the Carruthers family suffered a great loss when George’s father died suddenly, leaving the mother and four children. They moved to Chicago, Sophia Carruthers’s hometown, in 1951, and George continued his education there, graduating from Englewood High School in 1957. Chicago offered excellent opportunities to learn about science because of its outstanding museums, especially the Field Museum of Natural History, the Museum of Science and Industry, and the Adler Planetarium, and George took advantage of these opportunities. His enthusiasm for space science was reflected in his joining the Chicago Rocket Society. Through his school, he entered several science fairs in which he received recognition for his scientific knowledge and inventiveness.

Following high school, Carruthers entered the University of Illinois, concentrating on physics, aeronautical engineering, and astronomy. After graduating in 1961 with a bachelor of science degree, he stayed on at Illinois for graduate work, obtaining a master’s degree in the following year and a Ph.D. in 1964. His doctorate was in aeronautical and astronautical engineering. During his graduate career, he carried out several important experiments dealing with plasmas, especially in relation to plasma rocket engines and spacecraft reentry problems.

Life’s Work

Carruthers’s began his scientific career at the Naval Research Laboratory (NRL) in Washington, D.C. He joined its rocket research group immediately after receiving his Ph.D., first as a National Science Foundation postdoctoral fellow and later as a research physicist in the Naval Research Laboratory’s Hulburt Center for Space Research.

By 1964, space science had become a major activity in the United States. Orbiting spacecraft proliferated, and new opportunities for studying the planets and stars were opening up. One of these opportunities was the study of ultraviolet (UV) radiation emitted by cosmic sources. Ultraviolet light is absorbed by Earth’s atmosphere, and ground-based scientists had not been able to detect it. Carruthers was interested in finding a good way to detect, measure, and study ultraviolet light from space. He carried out some experiments with suborbital sounding rockets, which reached high enough above most of the atmosphere to detect the ultraviolet light. In 1966, Carruthers’s newly invented ultraviolet detector was successfully flown on a sounding rocket. In 1969, he patented the design for an ultraviolet camera, which was called an “Image Converter for Detecting Electromagnetic Radiation Especially in Short Wave Lengths.” Subsequent experiments led to a major achievement in 1970 when his rocket-borne camera detected molecular hydrogen in space for the first time. Astronomers knew that hydrogen was abundant in the universe, as atomic hydrogen could be detected from the ground and was clearly the most common atom in space. However, in its molecular form, it had never been seen before, and Carruthers’s camera proved an important new window into the universe.

Carruthers’s results from rocket flights were impressive, especially considering the very short time the camera was above the atmosphere. To get better results, it was realized that the ultraviolet camera should be mounted on a telescope on a firm platform in space so that longer exposures could be made. The first opportunity for this came in 1972, when the Apollo 16 crew set up the Far-Ultraviolet Camera/Spectrograph on the lunar surface. Carruthers was the principal investigator and chief engineer for the experiment. The telescope and camera worked well, and the scientific results were superb, including UV images and spectroscopic data for both Earth atmospheric studies and stellar astrophysical measurements. In 1974, a backup camera from the Apollo mission was taken into space to be used on Skylab 4. Several experiments were carried out, including a first look at the UV light from a comet, as Comet Kohoutek was near the Earth at that time.

While satellite and lunar experiments were undoubtedly very productive, they were also very expensive and rarely available. For that reason, during this era Carruthers continued to use sounding rockets, which were much cheaper and more available, for science and engineering experiments. For instance, he was able to take advantage of the 1986 passage of Halley’s comet to obtain some important ultraviolet observations of the hydrogen emission from the corona (the outer atmosphere) of this most famous comet.

In the 1990’s, Carruthers was involved in using the Air Force’s Advanced Research and Global Observation Satellite (ARGOS) for orbital study of the Earth’s far-outer atmosphere, the electrically charged ionosphere and the neutral outer layers. His group developed a number of highly effective UV instruments for ARGOS deployment.

Carruthers retired from the NRL in 2002. He subsequently taught a course on Earth and space science at Howard University for several years. Carruthers died on December 26, 2020, from congestive heart failure. He was eighty-one years old.

Impact

Carruthers was a pioneer in the field of ultraviolet astronomy. His Far-Ultraviolet Camera, set up on the Moon’s surface by the Apollo 16 astronauts, produced about two hundred UV pictures of the Earth’s far-outer atmosphere and deep-space objects. For the first time in history, his device detected hydrogen in deep space, and it accurately measured the energy output of very hot stars.

Carruthers had a strong interest in teaching young people about science and its applications. In addition to talks to students at several universities, he was active in the work of Science, Mathematics, Aerospace, Research, and Technology (SMART), a group of scientists and engineers who provide training workshops for black teachers and students. Of the many awards that Carruthers received, the most notable are the Arthur S. Fleming Award (1971), the Exceptional Scientific Achievement Award (1972), an honorary doctorate from Michigan Technical University (1973), the University of Illinois Alumni Award (1975), the Samuel Cheevers Award (1977), the Black Engineer of the Year Award (1987), election to the National Inventors Hall of Fame (2003), and the National Medal of Technology and Innovation (2012).

Bibliography

Barstow, Martin A., and Jay B. Holberg. Extreme Ultraviolet Astronomy. Cambridge University Press, 2003. This technical book provides a complete history of the development of ultraviolet astronomy, which was pioneered by Carruthers. It includes details of the early years of ultraviolet astronomy, when sounding rockets carrying Carruthers’s detectors provided the first extraterrestrial detections of UV sources.

Carruthers, George. “Apollo 16 Far-Ultraviolet Camera/Spectrograph: Instruments and Operations.” Applied Optics, vol. 12, 1973, pp. 2501–2508. The ingenious and eminently successful Apollo 16 Far-Ultraviolet Camera, the first (and so far only) telescope to be used on the Moon, is described in detail. There are good diagrams and useful engineering details, but the paper is at a technical level.

Carruthers, George. “Television Sensors for Ultraviolet Space Astronomy.” In Astronomical Observations with Television-Type Sensors, edited by J. W. Glaspey and Gordon Arthur Hunter Walker. Institute of Astronomy and Space Science, University of British Columbia, 1973. This is probably Carruthers’s most important paper about his design and its relation to other instruments used for ultraviolet astronomy. It is fairly technical but well written, and it provides an excellent introduction to the engineering details of these kinds of instruments.

Henderson, Susan K., Stanley P. Jones, and Fred Amram. African-American Inventors II: Bill Becoat, George Carruthers, Meredith Gourdine, Jesse Hoagland, Wanda Sigur. Capstone Press, 1998. This short book is intended for high school-age readers. It provides the basic facts about the lives of five outstanding black inventors.

Kessler, James H., J. S. Kidd, Renée A. Kidd, and Katherine A. Morin. Distinguished African American Scientists of the Twentieth Century. Oryx Press, 1996. This encyclopedic book covers the lives and accomplishments of one hundred African American scientists and inventors. Its 392 pages are full of biographical data, arranged alphabetically and including a photograph of each person. Carruthers’s biography is four pages long. The book was written for young readers in clear and rather plain language.

Orloff, Richard W., and David M. Harland. Apollo: The Definitive Sourcebook. Springer Praxis Books, 2006. As the developer of the first telescope to be deployed on the surface of the Moon, George Carruthers was an important figure in the scientific success of the Apollo program. This thick and authoritative source book provides comprehensive accounts of each of the Apollo flights and summarizes the science attained. Its 633 pages are densely packed but are written in reasonably nontechnical language.

Sandomir, Richard. "George Carruthers, Whose Telescopes Explored Space, Dies at 81." The New York Times, 25 Jan. 2021, www.nytimes.com/2021/01/23/science/space/george-carruthers-dead.html. Accessed 29 Apr. 2021.