Sky & Telescope July 1991 [antikvár]

FOCAL POINTA Bright Future for Planetary Astronomy?A CENTURY AGO planetary astronomy was a major component of the work at most major observatories. Unfortunately, in the view of some astronomers and historians, the long "canals of Mars" controversy soured professional opinion of planetary astronomy and caused the discipline to remain an astronomical backwater for several decades. By the mid-1950's only a handful of astronomers, of whom Gerard Kuiper at Yerkes Observatory was the most senior, were observing the planets to study their physical properties, and hardly any students were being trained.In the United States, military and civilian interest in the Moon and planets began to grow in the mid-1950's and rapidly gained momentum in the months following the first Sputnik launch in 1957. As the newly formed NASA developed its earliest plans for space probes to the planets, there was insufficient information and no ready means of getting better data. In the decade of the 1960's NASA built three large telescopes, in Arizona, Texas, and Hawaii, dedicated to determining the basic properties of the Moon and planets.Recognizing that studies of the planets require an understanding of geology and atmospheric physics as well as astronomy, NASA also encouraged and supported the education of the first generation of mul-tidisciplinary planetary scientists. NASA justified the new telescopes, and to some degree the new scientists, as essential for planetary mission support.Thus reborn as NASA's child, planetary astronomy has been supported for nearly four decades by the space agency. Consequently, the National Science Foundation (NSF) and U. S. national observatories have found it easy to ignore the needs of solar system specialists. For all the achievements of the current generation of planetary astronomers, financial support has not kept pace with inflation and the resource demands of a modestly growing community of researchers. NSF spends about $1 million annually on solar system work, which is less than 10 percent of NASA's current planetary astronomy budget. Even NASA's funding has declined over the last decade to the point where many of the approximately 200 planetary astronomers are unable to accomplish their goals. Many of these scien-tists, particularly the younger ones, are turning to other kinds of work.Other resources have also dwindled. Since the opening of the Infrared Telescope Facility, the fourth and last of NASA's big telescopes, half the observing time has been allocated to solar system work, but the fraction of planetary time on the agency's other three telescopes has declined to about 20 percent or less. No more than three percent of the telescope time at the national facilities on Kitt Peak and Cerro Tololo is assigned to solar system work, and in the face of repeated rejections, few planetary astronomers now bother to apply.Since the beginning of NASA's support, planetary astronomers have felt a certain uneasiness in their relationship with more traditional astronomers, even though the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) now has 750 members, or about 14 percent of the total AAS membership. Planetary astronomy was largely ignored in the first three "decade surveys" of astronomy. In 1977 George Field cautioned DPS members not to expect much access to the Hubble Space Telescope (HST) for planetary objects. And in the original data-management plan for the Infrared Astronomical Satellite, all data on moving objects (planets, comets, and asteroids) were to have been discarded.In the face of this history, it is especially encouraging that solar system work has been factored into several major astrophysics projects such as the Space Infrared Telescope Facility, new instruments for HST, and the Stratospheric Observatory for Infrared Astronomy.Planetary astronomy and astrophysics are converging on a common interest in the search for and study of extrasolar planetary systems and preplanetary disks around other stars. As NASA's planetary program broadens its purview to include this endeavor, the agency has recognized the need to support a telescope of the largest size currently possible to construct. Accordingly, NASA has conveyed its interest in participating in the construction and operation of the Keck II a second 10-meter telescope that will be adjacent to the Keck 10-meter on Mauna Kea. Up to one third of the time on one telescope, or one sixth of the time on the two, will be used for NASA planetary programs.This positive development suggests a continuing commitment by NASA to the progress of planetary astronomy. However, the agency must not use this occasion to weaken support for its other telescopes. Clearly, planetary astronomers must gain training and experience before going to the world's largest telescope, and many compelling planetary problems can be pursued with instruments in the I- to 3-meter class.Thus the future of planetary astronomy appears bright in terms of the acquisition of data at the technological frontier. The major question is: will the small community of specialists survive the current funding crunch and maintain the pace of discovery in planetary astronomy? Having big equipment is not enough. The research community requires a steady source of funding commensurate with the quality of capital investment in both telescopes and trained people.