Sunday, June 21, 2009

Deceased--Frank J. Low

Frank J. Low
November 23rd, 1933 to June 11th, 2009

"Frank J. Low, Who Helped Drive Field of Infrared Astronomy, Dies at 75"


Dennis Overbye

June 21st, 2009

The New York Times

Frank J. Low, who helped astronomers extend their vision beyond visible light into a vast realm of previously invisible colors, revolutionizing the study of the birth of planets, stars and galaxies, died on June 11 in Tucson. He was 75.

His death, after a long illness, was announced by the University of Arizona, where he had been a professor since 1965.

Starting as a young physicist at Texas Instruments in 1961, Dr. Low spent his career developing devices to detect and measure infrared, or "heat," radiation from stars and getting them deployed in telescopes, airplanes and satellites.

Using Dr. Low's devices and their successors, astronomers have been able to peer through dust clouds to find the birthplaces of stars; discover galaxies and quasars invisible to ordinary telescopes; discern rings of dust and, recently, even planets around other stars; and study what is believed to be residual heat left over from the Big Bang.

NASA's next big effort, the James Webb Space Telescope, destined for a 2014 launching, is an infrared space telescope built in a design Dr. Low created.

Dr. Low helped drive the field of infrared astronomy with his enthusiasm and an intuitive knack for solving technical problems, said George H. Rieke, a longtime associate at the University of Arizona. Along with Gerry Neugebauer of Caltech and the late Harold L. Johnson of Arizona, Dr. Low was a co-father of the field, Dr. Rieke said.

Frank James Low was born in Mobile, Ala., on Nov. 23, 1933, and reared in Houston. He studied physics at Yale University and then Rice University, where he earned a Ph.D. in 1959.

He then joined Texas Instruments, where he developed a low-temperature thermometer made of the rare-earth element germanium doped with trace amounts of gallium. Dr. Low realized that the device, which responded to absorbed energy by changing its electrical resistance, could be used as an infrared bolometric detector that could measure heat from stars.

Every object in the universe — from a fevered brow to an exploding star — emits some of this heat, which consists of electromagnetic waves longer than visible light waves but shorter than radio waves. For several years, astronomers, including Dr. Johnson, had been trying to tap into this radiation.

Dr. Low's bolometer was more sensitive than previous detectors, and he was eager to put it to work. In 1962, he moved from Texas Instruments to the National Radio Astronomy Observatory in Green Bank, W.Va. There, he tested his bolometer on a radio telescope.

Besides being invisible, infrared rays also are absorbed by the atmosphere, especially water vapor, so a high, dry place is necessary for infrared astronomy. Dr. Low solved this problem by going above the atmosphere's water vapor and initiating airborne astronomy, using ever larger and higher-flying laboratories: a U.S. Navy Douglas A-3 bomber carrying a 2-inch telescope in 1965 and 1966; and a NASA Learjet, Dr. Low's favorite, with a 12-inch telescope.

With the Learjet, he discovered that Jupiter and Saturn emitted more energy than they received from the Sun, which meant they had some source of internal energy. In 1975, NASA began operating the Gerard P. Kuiper Airborne Observatory, a converted Lockheed C-141 military cargo plane, but Dr. Low continued to use the Learjet.

The Kuiper is soon to be replaced by a modified Boeing 747SP, called SOFIA, for Stratospheric Observatory for Infrared Astronomy.

Yearning to be completely free of atmospheric interference, Dr. Low, along with other astronomers, pushed NASA to build and launch the Infrared Astronomy Satellite, IRAS, which did the first infrared sky survey from space. Dr. Low was its chief technologist.

When an accident at the Jet Propulsion Laboratory destroyed the preamplifiers for the satellite's detectors, throwing the project into a crisis, Dr. Low built new and better ones at his own company, Infrared Laboratories Inc., which he had founded in 1967 to supply astronomers around the world.

Launched in 1983, IRAS — a joint venture by the United States, the United Kingdom and the Netherlands — pinpointed more than half a million sources of infrared radiation in the sky, many of them galaxies. Indeed, astronomers now say that half of the energy released by galaxies is in the form of infrared emission, created when interstellar dust absorbs light from young stars and re-radiates it as heat.

IRAS also discovered rings of debris and dust around other stars, in particular Vega, suggesting that the same processes that had formed planets close at hand were at work deep in space.

Astronomers later found a similar debris field, the Kuiper Belt, which lies beyond Neptune. Dr. Rieke called it "certainly the first example of discovering a feature in other planetary systems before we found it in our own."

NASA planned to follow IRAS with a Hubble-class infrared satellite called the Space Infrared Telescope Facility, now known as the Spitzer Space Telescope. Dr. Low was named the facility scientist, but the project was stalled for years by cost concerns.

At a retreat for the project scientists and engineers in Colorado in 1993, Dr. Low had a midnight inspiration for how to build the telescope more cheaply.

Previously, to keep infrared telescopes from being swamped by their own heat, the telescopes were encased in a giant thermos bottle and cooled to nearly absolute zero by liquid helium. Dr. Low proposed leaving the telescope out in the open and letting it radiate its heat to space naturally. Only the detectors at the focal plane of the telescope needed to be cooled with liquid helium.

Dr. Low's design saved the project and opened up a new way to build space telescopes, including the coming James Webb Space Telescope, Dr. Rieke said.

Dr. Low retired from the University of Arizona in 1996, after 31 years; he also maintained a connection with Rice University from 1966 to 1979. He remained active in his company until 2007.

He is survived by his wife of 52 years, Edith Low; three children, Valerie Rossiter of Tucson, Beverly Fjeldstad of Oslo, Norway, and Eric Low of Rogers, Ariz.; a sister, Sallie Beckner of Washington; and six grandchildren.

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