Infrared Instrumentation. The ongoing revolution in infrared technology can improve the data-collection capability of existing telescopes by factors of tens of thousands by replacing single-element detectors with large, multielement arrays. Building instruments that incorporate arrays will enhance both imaging and spectroscopic capabilities.
Cosmic Background Imager. On angular scales smaller than a few degrees, the cosmic background radiation reflects conditions in the early universe at an age of only 100,000 years. Recent technological advances suggest that a Cosmic Background Imager could reach the levels of sensitivity required to search for variations in the brightness of the background in different directions. Primordial density fluctuations that may be the precursors of galaxies can be revealed by these variations in brightness.
Laboratory Astrophysics. The interpretation of observations from ground-based telescopes often depends on the results of laboratory experiments concerning basic atomic, molecular, or nuclear data. In some cases, theoretical calculations are necessary because the appropriate quantities cannot be measured. Since many important experiments in laboratory astrophysics are primarily of interest to astronomers, some laboratory research will require direct funding from astrophysics resources.
Other Programs. Other important small projects listed in Table 1.1 are a ground-based facility for making long-term astrometric measurements, U.S. participation in an international project to build a 300-m radio telescope in Brazil, instrumentation to study the “seismology” of stars, optical all-sky surveys of galaxies with modern electronic detectors, and systematic monitoring to detect neutrino bursts from supernovae. Details of these and other projects are described in the Working Papers.
Small Explorers. The committee highlights an acceleration of the Small Explorer (SMEX) program to be carried out within tight budgetary constraints with the goal of making possible five astronomy SMEX missions in the 1990s. These small new missions should be selected by the peer review process and launched on Scout-class rockets. SMEX missions will help train the future leaders of space astronomy and will provide a rapid method for executing certain well-defined, high-priority projects. Some of the panel reports in the Working Papers contain excellent ideas for SMEX payloads.
Other Projects. Other space projects that will return important data at relatively low cost include U.S. participation in a German orbiting planetary telescope, and orbiting very long baseline interferometry (VLBI) experiments being conducted with the Soviet Union and Japan. The success of future