Lyman Spitzer Jr and the Vision of Space Based Astronomy

In 1946, more than a decade before the launch of the first artificial satellite, the American astrophysicist Lyman Spitzer Jr. (1914-97) proposed the development of a large, space-based observatory that could operate unhindered by distortions in Earth's atmosphere. His vision ultimately became NASA's Hubble Space Telescope, which was launched in 1990. Spitzer was a renowned astrophysicist who made major contributions in the areas of stellar dynamics, plasma physics, and thermonuclear fusion, as well as space-based astronomy. NASA launched the Space Infrared Telescope Facility in 2003 and renamed this sophisticated new space-based infrared telescope the Spitzer Space Telescope in his honor.

Spitzer was born on June 26, 1914, in Toledo, Ohio. He attended Yale University, where he earned his bachelor's degree in physics in 1935. Following a year at Cambridge University, he entered Princeton University, where he earned his master's degree in 1937 and then a doctorate in astrophysics in 1938. His mentor and doctoral adviser was the famous American astronomer Henry Norris Russell (1877-1957). After getting his Ph.D., Spitzer spent a year as a postdoctoral fellow at Harvard University, after which he joined the faculty of Yale University (1939).

During World War II, Spitzer performed underwater sound research, working with a team that led the development of sonar. When the war was over, he returned for a brief time to teach at Yale University. In 1946, more than a decade before the first artificial satellite (Sputnik 1) was launched into space and 12 years before NASA was created, Spitzer proposed the pioneering concept of placing an astronomical observatory in space—where it could observe the universe over a wide range of wavelengths and not have to deal with the blurring (or absorbing) effects of Earth's atmosphere. He further proposed that a space-based telescope would be able to collect much clearer images of very distant objects in comparison to any

The American astronomer Lyman Spitzer Jr. was a strong advocate for space-based astronomy. (NASA/Denise Applewhite/Princeton University)

ground-based telescope. To support these views, Spitzer wrote "Astronomical Advantages of an Extra-Terrestrial Observatory." In this visionary paper, he enumerated the advantages of putting a telescope in space. He would then invest a considerable amount of his time over the next five decades to serve as an enthusiastic lobbyist for a telescope in space, both with members of the U.S. Congress and with fellow scientists. His efforts were instrumental in the development of the Hubble Space Telescope.

In 1947 Spitzer received an appointment as chairman of Princeton University's astrophysical sciences department. Accepting this appointment, he succeeded his doctoral adviser, Henry Norris Russell. Spitzer also became the director of Princeton's observatory. While at Princeton, he made many contributions to the field of astrophysics. For example, he thoroughly investigated interstellar dust grains and magnetic fields, as well as the motions of star clusters and their evolution. He also studied regions of star formation and was among the first astrophysicists to suggest that bright stars in spiral galaxies formed recently from the gas and dust there. Finally, he accurately predicted the existence of a hot galactic halo surrounding the Milky Way Galaxy.

In 1951 Spitzer founded the Princeton Plasma Physics Laboratory (originally called Project Matterhorn by the U.S. Atomic Energy Commission). This laboratory became Princeton University's pioneering program

The Hubble Space Telescope with its aperture door open, floating majestically in space. This image was taken by the crew of the space shuttle Discovery in February 1997, during the STS-82 servicing mission. (NASA/JSC)

in controlled thermonuclear research. Spitzer promoted efforts to harness nuclear fusion as a clean source of energy and remained the laboratory's director until 1967. Then, in 1952, Spitzer became the Charles A. Young Professor of Astronomy at Princeton. He retained that prestigious title for the rest of his life.

From 1960 to 1962, Spitzer served as president of the American Astronomical Society. As the fledging U.S. space program emerged in the 1960s, Spitzer's visionary idea for space-based astronomy finally began to look more promising. In 1962 he led a program to design an observatory that would orbit the Earth and study the ultraviolet light from space. Earth's atmosphere normally blocks ultraviolet (UV) light, so scientists cannot study UV emissions from cosmic sources using ground-based facilities. This proposed observatory eventually became NASA's Copernicus spacecraft, which operated successfully between 1972 and 1981. (Chapter 8 discusses ultraviolet astronomy.)

In 1965 the National Academy of Sciences established a committee to define the scientific objectives for a proposed large space telescope, and the academy selected Spitzer to chair this committee. At the time, many astronomers did not support the idea of a large space-based telescope. They were concerned, for example, that the cost of an orbiting astronomical facility would reduce the government's financial support for ground-based astronomy. Spitzer invested a great personal effort to convince members of the scientific community, as well of the U.S. Congress, that placing a large telescope into space had great scientific value. In 1968 the first step in making Spitzer's vision of putting a large telescope in space came true. That year NASA launched its highly successful Orbiting Astronomical Observatory series of scientific spacecraft. An observatory spacecraft is a space robot that does not travel to a destination to explore. Instead this type of robot spacecraft travels in an orbit around Earth or around the Sun, from where the observatory can view distant celestial targets unhindered by the blurring and obscuring effects of Earth's atmosphere.

Through the early 1970s, Spitzer continued to lobby NASA and the U.S. Congress for the development of a large space telescope. Finally, in 1975, NASA, along with the European Space Agency, began development of what would eventually become the Hubble Space Telescope. In 1977, due in large part to Spitzer's unflagging efforts, the U.S. Congress approved funding for the construction of NASA's Space Telescope—an orbiting facility eventually named the Hubble Space Telescope in honor of the great American astronomer Edwin P. Hubble (1889-1953). In 1990, more than 50 years after Spitzer first proposed placing a large telescope into space, NASA used the space shuttle to successfully deploy the Hubble Space Telescope in orbit around Earth. Refurbished several times on orbit-servicing

NASA's Orbiting Astronomical Observatory

NASA launched a series of large astronomical observatories in the late 1960s to significantly broaden scientific understanding of the universe. The first successful large observatory placed in Earth's orbit was the Orbiting Astronomical Observatory 2 (OAO-2), nicknamed Stargazer, which was launched on December 7, 1968. In its first 30 days of operation, OAO-2 collected more than 20 times the celestial ultraviolet data than had been acquired in the previous 15 years of sounding rocket launches. Stargazer also observed Nova Serpentis for 60 days after its outburst in 1970. These observations confirmed that mass loss by the nova was consistent with theory. NASA's Orbiting Astronomical Observatory 3, named Copernicus in honor of the famous Polish astronomer Nicholas Copernicus, was launched successfully on August 21, 1972. This satellite provided much new data on stellar temperatures, chemical compositions, and other properties. It also gathered data on the black hole candidate Cygnus X-1, so named because it was the first X-ray source discovered in the constellation Cygnus.

missions by the space shuttle, the Hubble Space Telescope still provides scientists with stunning images of the universe and still produces amazing new discoveries. (The Hubble Space Telescope is discussed in chapter 4.)

At the age of 82, Spitzer passed away on March 31, 1997, in Princeton, New Jersey. NASA launched a new space telescope on August 25, 2003. This space-based observatory consists of a large and lightweight telescope and three cryogenically cooled science instruments capable of studying the universe at near- to far-infrared wavelengths. Incorporating state-of-the-art infrared detector arrays, and launched into an innovative Earth-trailing solar orbit, the observatory is orders of magnitude more capable than any previous space-based infrared telescope. NASA named this new facility the Spitzer Space Telescope in honor of Spitzer's vision of and contributions to space-based astronomy. (The Spitzer Space Telescope is discussed in chapter 7.)

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