George R. Carruthers 1939–

Astrophysicist

Determined to Become a Rocket Scientist

Joined the NRL

Examined Space with UVC

Worked with NASA and ARGOS

Promoted Careers in Science and Engineering

Selected writings

Sources

George R. Carruthers, an internationally-renowned astrophysicist, is a pioneer in the use of ultraviolet astronomy for studying the Earth, our Solar System, and the universe. He has spent his career in the Space Science Division of the Naval Research Laboratory (NRL) in Washington, D.C., developing space telescopes and other photometric instruments, in collaboration with the National Aeronautics and Space Administration (NASA). Carruthers invented the far ultraviolet camera/spectrograph (UVC), also known as the lunar surface ultraviolet camera. This imaging instrument was flown to the moon on the 1972 Apollo 16 mission, where it used ultraviolet light to obtain images of Earth and outer space.

Determined to Become a Rocket Scientist

George Robert Carruthers was born on October 1, 1939, in Cincinnati, Ohio, the oldest of four children of George and Sophia Carruthers. When he was seven, his family moved to the Cincinnati suburb of Milford, a small town where he attended grade school. Science fiction and comic books, especially Buck Rogers, inspired his early interest in space exploration and Carruthers began reading his father’s astronomy books. His father, a civil engineer with the U.S. Army Air Corps, encouraged his interests and bought him books so he could study math and science beyond what was covered in school. Carruthers built model rockets. By the age of ten, he had constructed his own telescope with cardboard tubing and mail-order lenses that he bought with the money he earned as a delivery boy.

His father died when Carruthers was 12. The family moved to Chicago and his mother went to work for the U.S. Postal Service. Carruthers often visited the nearby Museum of Science and Industry, the Field Museum, and the Chicago Planetarium. Although he was not a particularly good student in math and physics, his science teachers encouraged him and helped him build telescopes. Carruthers won three science fair awards, including first prize for a telescope that he designed and built. He was one of the very few black students to participate in the science fairs, which were usually held at predominantly white schools.

Carruthers graduated from Chicago’s Englewood High School in 1957 and entered the College of Engineering at the University of Illinois’ Champaign-Urbana campus. It was the beginning of the space age and astronomers were considering the potential of space-based observations. Carruthers was thinking about telescopes mounted on satellites, where the views would be unimpeded by the Earth’s atmosphere. His undergraduate program combined aerospace engineering and astronomy. As he explained on a videoclip prepared for a Powers of Ten Interactive CD, “There is no sharp dividing line between science and engineering because scientists, like myself, often design their own hardware, and sometimes engineers do research on such things as properties of materials. And it’s very difficult to draw a sharp line between what an engineer does and what a scientist does.”

At a Glance…

Born George Robert Carruthers on October 1, 1939, in Cincinnati, OH; son of George and Sophia Carruthers. Education: University of Illinois, BS, 1961, MS, 1962, PhD, 1964.

Career: Naval Research Laboratory, Space Science Division, rocket astronomy research physicist, 1964-82, head of Ultraviolet Measurements Branch, 1980-82, senior astrophysicist, 1982-.

Memberships: American Association for the Advancement of Science; American Astronomical Society; American Geophysical Union; American Institute of Aeronautics and Astronautics; National Technical Association, chairman of editorial review committee, journal editor, 1983-; SMART, Inc, vice president, 1995-; Smithsonian Institute, council member, 1995-; Society of Photo-optical Instrumentation Engineers.

Awards: Arthur S. Fleming Award, Washington Jaycees, 1971; Exceptional Scientific Achievement Medal, NASA, 1972; Warner Prize, American Astronomical Society, 1973; Exceptional Achievement Award, National Civil Service League, 1973; honorary doctorate, engineering, Michigan Technical University, 1973; Alumni Award, University of Illinois, 1975; Samuel Cheevers Award, National Technical Association, 1977; Black Engineer of the Year, 1987; National Inventors Hall of Fame, 2003.

Address: Office —Code 7645, U.S. Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, DC 20375-5000.

Joined the NRL

After earning his bachelor’s degree in physics in 1961, Carruthers stayed on at the University of Illinois. He earned his master’s degree in nuclear engineering in 1962 and his doctorate in aeronautical and astronautical engineering in 1964. One of his first graduate school projects was to experiment with a plasma rocket engine. A high-intensity electrical power supply heated helium gas to such a high temperature that the helium molecules separated, expelling the super-hot gas or plasma and driving the rocket engine. Carruthers constructed a working model of his plasma engine as a demonstration for his introductory astrophysics students. He also began analyzing one of the major problems of space flight—the super-hot gases that are formed by the friction between the skin of the spacecraft and atmospheric gases, as the craft descends at high speed. These hot gases can damage the spacecraft. For his Ph.D. research Carruthers experimented with the recombination of atomic nitrogen.

Since high school Carruthers had been following the work of the NRL’s rocket astronomy group. In 1964 he went to work there as a National Science Foundation postdoctoral fellow. Two years later he became a full-time research physicist at the NRL’s E. O. Hurlburt Center for Space Research.

Carruthers worked on obtaining images using the ultraviolet (UV) region of the electromagnetic spectrum. These are wavelengths of light that are shorter than those of visible light but longer than x-rays. Many elements, including hydrogen, oxygen, nitrogen, and carbon, have unique spectral lines in the far-UV region. Far-UV imaging enables scientists to detect and measure these elements in their unexcited or ground states. It provides more accurate measurements of the chemical compositions of planetary atmospheres and interstellar gases. It also provides information about solid particles in interstellar space and more accurate measurements of the energy emitted by very hot stars. Two of Carruthers’s early publications, on the concentration of molecular hydrogen in interstellar space and on the far-UV spectroscopy and imaging of stars, established his reputation as a brilliant astrophysicist.

Examined Space with UVC

On November 11, 1969, Carruthers was awarded a patent for his “Image Converter for Detecting Electromagnetic Radiation Especially in Short Wave Lengths.” Since the Earth’s atmosphere absorbs most UV emissions, UV spectrographs and cameras operating in space provide much more information than those on Earth. For example, although prevalent on Earth, molecular hydrogen had never been detected in interstellar space because its spectral lines are in the far-UV and don’t penetrate the Earth’s atmosphere. To observe hydrogen in space, the interstellar medium must be illuminated by a distant star and the spectrum recorded.

During a 1970 sounding rocket flight, Carruthers’s UV telescope and image converter provided the first proof of the existence of molecular hydrogen in interstellar space. Sounding rockets do not achieve orbit, but fly up about 120 miles. Carruthers’s carefully calibrated instrument was designed to withstand the stresses of Earth’s magnetic field, cosmic rays, and outgassing—the sudden vacuum of space. Furthermore its guidance system had to find and track the chosen star in the five minutes of the rocket’s flight. Its camera system was electronically intensified to be very sensitive. The discovery of interstellar molecular hydrogen confirmed that hydrogen—the simplest, lightest, and smallest atom—is the predominant element in the universe.

The UVC was first tested on sounding-rocket flights in 1966. Then, on April 21, 1972, during the first lunar walk of the Apollo 16 mission, the astronauts placed the 50-pound (22-kilogram) UVC in the shadow of the lunar module. It was mounted on a tripod and gold-plated to protect it from overheating. In designing the UVC, Carruthers and his team had to consider the stress of the journey and ability of the instrument to function in a vacuum and under low-gravity conditions. It also had to be simple enough for the astronauts to operate. However, Carruthers had solved the most difficult of these problems during his sounding-rocket work. The instrument provided spectroscopic data in the wavelength range of 300 to 1350 angstrom units with a 30-angstrom resolution.

The UVC was a high priority for Apollo 16 and Carruthers was its principal investigator and chief engineer. The instrument took some 200 UV pictures of 11 selected targets. For the first time, scientists were able to examine large expanses of the Earth’s atmosphere for concentrations of pollutants. In an historic picture, using a 20-minute exposure, the UVC provided the first full view of the Earth’s hydrogen geocorona that extends thousands of miles into the far-outer atmosphere. It also took the first full images of the outer atmosphere airglow belts of ionized gases that reflect radio waves. It provided new far-UV images of more than 550 stars, nebulae, and galaxies. The film was removed from the camera and the UVC was left on the moon. However, the backup unit, with several modifications, was used on Skylab 4 for observations of comet Kohoutek in 1974. Although its telescope was not particularly powerful, the UVC demonstrated the utility of extraterrestrial observations that culminated with the Hubble Space Telescope. Carruthers was awarded NASA’s Exceptional Scientific Achievement Medal for his work on the project.

Worked with NASA and ARGOS

Carruthers has been a principal investigator on many NASA and Department of Defense space research instrument projects. Cameras developed by Carruthers and his colleagues have flown on numerous sounding-rocket and space-shuttle flights, measuring the Earth’s ozone layer and upper atmosphere, and sending back far-UV images of distant stars and planets for analysis. In 1986 one of his rocket instruments obtained a UV image of Halley’s comet.

Carruthers has been at the forefront of the development of electronic telescopes that are used on NASA satellites. These telescopes increase the intensity of light from planets and distant stars, transform the light into electrical signals, and transmit the images back to Earth. Scientists use this information to study the formation of new stars and planets from interstellar dust and gas.

The makeup of the interstellar medium remains one of Carruthers’s major research interests. He works with the Air Force Space Test Program’s ARGOS or Advanced Research and Global Observation Satellite, directing the design and testing of new instruments. The Global Imaging Monitor of the Ionosphere (GIMI) is used to map, measure, and monitor the ionosphere and the neutral atmosphere, including auroras and other near-Earth space phenomena, as well as celestial objects. It has two cameras for simultaneous observations of ionospheric airglow emissions, with the goal of improving radar transmissions, especially during ionospheric disturbances. The GIMI was used to measure atomic nitrogen in the upper atmosphere by imaging nitric oxide nightglow emissions resulting from the combination of atomic nitrogen and atomic oxygen.

Carruthers’s other ARGOS projects are high-resolution airglow/aurora spectroscopy (HIRAAS) and the extreme ultraviolet imaging photometer (EUVIP). The ARGOS mission that launched in 1999 obtained an image of a meteor from a Leonid meteor shower as it entered the Earth’s atmosphere. It was the first time that a meteor had been imaged in the far-UV from a camera in space.

Promoted Careers in Science and Engineering

The co-author and editor of numerous scientific reports, Carruthers also taught. He spent a year teaching astrophysics at Johns Hopkins University in Baltimore and he was a member of two independent scientific review committees for the Hubble Space Telescope Project. As of 1995 there were only about 15 black professional astronomers in the United States. Carruthers actively promotes science and technology among young people, particularly young blacks. He has been a member of Science, Mathematics, Aerospace, Research, and Technology (SMART), Inc. since 1990 and its vice president since 1995. Project SMART encourages black teachers and students to pursue science and technology through local training workshops. Carruthers has worked with the NRL’s Community Outreach Program and other educational and community organizations, supporting science education at high schools in the Washington, D.C. area. He co-produced a video series on Earth and space for high school students. In addition to his memberships in numerous professional organizations, since 1983 Carruthers has chaired the editorial review committee of the National Technical Association and edited its journal. This organization promotes career development for minority scientists.

Carruthers lectures frequently, both on his research and on more general topics such as the contributions of space missions to our understanding of the origins of stars, planets, and life in the universe. His lectures deal with remote-sensing missions, such as the Hubble Space Telescope and the Next Generation Space Telescope, as well as missions to explore the Solar System, including current and planned missions to Mars. As part of the Smithsonian Institution Lemelson Center’s “Innovative Lives” series, Carruthers has discussed being a real-life rocket scientist with middle-school students.

In May of 2003 Carruthers was inducted into the National Inventors Hall of Fame, in recognition of his invention of the UVC. This 31st annual induction recognized pioneers in the aviation and aerospace industries, to commemorate the centennial of the Wright Brothers’ first powered flight. The National Inventors Hall of Fame honors patented inventions that promote human, social, and economic progress. Carruthers told their press office, “One of the things that makes it very exciting and interesting is that in the early days of the space program almost every flight was something that was breaking new ground—especially in the astronomy area where we were previously limited to telescopes from the ground.”

Selected writings

Books

“Television Sensors for Ultraviolet Space Astronomy,” Astronomical Observations with Television-Type Sensors, Institute of Astronomy and Space Science, University of British Columbia, 1973.

(With Thornton Page and Richard Hill) S201 Catalog of Far-Ultraviolet Objects, Naval Research Laboratory, 1978.

(With Timothy D. Seeley) “Global Imaging Monitor of the Ionosphere: An Ultraviolet Ionospheric Imaging Experiment for the ARGOS Satellite,” Instrumentation for Planetary and Terrestrial Atmospheric Remote, Society of Photo-optical Instrumentation Engineers (SPIE), 1992.

(With Jeff S. Morrill, Brian C. Dohne, and Susan A. Christensen) “Air Force Program-675 Far-Ultraviolet Cameras Experiment: Observations of the Far-UV Space Environment,” Ultraviolet Technology IV, SPIE, 1993.

(With Brian C. Dohne, Kevin K. Shephard, Susan A. Reeb, and Edward G. Schmidt) “Photometric Calculations of the AFP-675 Far-Ultraviolet Cameras Experiment,” Ultraviolet Technology V, SPIE, 1994.

(With Timothy D. Seeley) “Global Imaging Monitor of the Ionosphere (GIMI): A Far-Ultraviolet Imaging Experiment on ARGOS,” Ultraviolet Atmospheric and Space Remote Sensing: Methods and Instrumentation, SPIE, 1996.

(With Kenneth F. Dymond) Ultraviolet Atmospheric and Space Remote Sensing: Methods and Instrumentation II, SPIE, 1999.

“Ultraviolet Spectroscopy in Astronomy,” Ultraviolet Spectroscopy and UV Lasers, Marcel Dekker, 2002.

Periodicals

“Magnetically Focused Electronographic Image Converters for Space Astronomy Applications,” Applied Optics, 1969.

“Far-Ultraviolet Photography of Orion: Interstellar Dust,” Science, 1970.

“Apollo 16 Far-Ultraviolet Camera/Spectrograph: Earth Observations,” Science, 1972.

“Apollo 16 Far-Ultraviolet Camera/Spectrograph: Instrument and Operation,” Applied Optics, 1973.

“Astronomy with the Space Shuttle,” Sky and Telescope, 1974.

“Far-Ultraviolet Rocket Survey of Orion,” Sky and Telescope, 1977.

“The Hydrogen Coma of Comet P-Halley Observed in Lyman Alpha Using Sounding Rockets,” Astronomy and Astrophysics, 1992.

“Outreach Programs for African-American Students in Washington, D.C.,” Mercury, 1995.

“Space Research in the Department of Defense,” Ad Astra, 2002.

Sources

Books

Henderson, Susan K., Stanley P. Jones, and Fred Amram, African-American Inventors II: Bill Be-coat, George Carruthers, Meredith Gourdine, Jesse Hoagland, Wanda Sigur, Capstone Press, 1998.

Kessler, James H., J. S. Kidd, Renee A. Kidd, and Katherine A. Morin, Distinguished African American Scientists of the 20th Century, Oryx Press, 1996, pp. 36-39.

Morrison, Philip and Phylis Morrison, The Ring of Truth: An Inquiry into How We Know What We Know, Random House, 1987.

Spady, James G., ed. by Ivan Van Sertima, Blacks in Science: Ancient and Modern, Transaction Books, 1984, pp. 258-65.

Periodicals

Ebony, October 1973, pp. 61-63.

New York Times, April 22, 1972, p. 1.

On-line

“Far-Ultraviolet Camera/Spectroscope,” NSSDC Master Catalog: Experiment, http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1972-031C&ex=10 (May 1,2003).

“George Carruthers,” About Inventors, http://inventors.about.com/library/inventors/blcarruthers.htm (May 1, 2003).

“George Carruthers,” Powers of 10, www.powersof10.com/powers/people/station_172.html (May 1, 2003).

“George Carruthers to be Inducted into National Inventors Hall of Fame for Inventing Far Ultraviolet Electrographic Camera,” National Inventors Hall of Fame, www.invent.org/hall_of_fame/l_3_0_induction_farelec.asp (May 6, 2003).

“George R. Carruthers,” The Faces of Science: African Americans in the Sciences, www.princton.edu/~mcbrown/display/carruthers.html (May 6, 2003).

“George R. Carruthers,” Physicists of the African Diaspora, www.math.buffalo.edu/mad/physics/carruthers-georger.html (April 29, 2003).

“Inventor of the Week,” Lemelson MIT Program, http://web.mit.edu/invent/iow/carruthers.html (May 1, 2003).

—Margaret Alic