processing data from radio interferometers. Many astronomers have adopted IRAF or AIPS in preference to the daunting task of developing their own codes. But researchers who want to make novel or demanding uses of state-of-the-art instruments find general-purpose software stifling; they may need a special calibration algorithm for their instrument that is not in the package. These astronomers find it difficult to integrate innovative data-reduction techniques into a large, centrally maintained package.
No perfect solution to this problem is yet in hand. To make effective use of the enormous advances in computer hardware and astronomical instrumentation expected in the next decade, astronomers will need an accompanying development of scientific software. Standard packages with modern interfaces are needed for users of optical and infrared telescopes whose needs are relatively standard. Programs consisting of 100,000 lines of code often require tens of person-years to develop, followed by a comparable and continuing effort to modernize, maintain, and document. Yet such packages are often difficult to modify for researchers interested in extracting the maximum possible information from their data. New architectures are needed that will provide both an open framework, within which an innovative user can develop and subsequently share new techniques, and a powerful set of fundamental tools for the general user. The development of such programs represents a major challenge to astronomers and to computer professionals. It is vital for both NASA and NSF to augment their efforts in the development, maintenance, and augmentation of community software.
There are compelling scientific reasons for archiving selected astronomical data from ground- and space-based telescopes. First, astronomical processes occur on time scales that are long compared to the lifetimes of individual researchers. The history of astronomy includes many instances when archival material dating back decades, and sometimes centuries, has proven essential in solving modern problems. Astronomers have an obligation to preserve contemporary data in an intelligible form for future generations of astronomers. Second, it is widely recognized that the definitive interpretations of much space astrophysics data are not found in the first papers, but rather in more extensive archival studies. Third, the large two-dimensional detectors of the 1990s will produce images of the sky taken at different wavelengths and at different times. Archival researchers can reanalyze these rich datasets to answer new questions and to make serendipitous discoveries.
The volume of data that will be gathered in the 1990s amounts to many terabytes per year. NASA's astronomy missions alone will generate about 10 terabytes of data annually. NASA is setting up the Astrophysics Data System to ensure wide and rapid access to data obtained from space observations;