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would normally be for a five-year period and the entire program would be subject to a senior review after
five years. These networks fulfill a different role from the NASA Astrophysical Theory Program and the
NSF AAG Program and should not be funded at their expense. For NSF’s AAG program the success rate
for theory proposals is roughly 37%.
DATA AND SOFTWARE
The scientific richness and extent of astronomical datasets is increasing rapidly. The sizes of
modern databases have grown over the past decade in to the petabyte (one million gigabytes) range, with
present growth of roughly 0.2 petabytes per year. Challenges for data archiving will increase dramatically
in the future. The committee’s top-ranked ground project, the Large Synoptic Survey Telescope (LSST),
expects its archive to grow by a petabyte per month. A complete SKA operated in the manner of the
VLA or ALMA would operate in the thousand petaflop or exaflop (one thousand petaflops) scale
compared to the petaflop of sustained power consumed by current astronomical computing. Proper
maintenance and accessibility of these archives is essential to optimizing scientific return, especially for
LSST studies of transient and time variable phenomena where rapid availability of validated data will be
critical.
As discussed in Chapter 3, the AAAC can play a key role in providing tactical advice to DOE,
NASA, and NSF on the support of data archiving and dissemination, and data analysis software funding
across the three agencies relative to the agencies’ programmatic needs as identified by Astro2010. In
particular, the optimal infrastructure for the curation of archival space and ground-based data from
federally supported missions/facilities will need periodic attention.
Data Archives
Data archives are central to astronomy today, and their importance continues to grow. The
science impact of these archives is large and increasing rapidly. Papers based on archival data from the
Hubble Space Telescope now outnumber those based on new observations in any year and include some
of the highest-impact science from the HST, as shown in Figures 5-6 and 5-7. Data from the 2 Micron All
Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS), which were both designed as archival
projects, led to more than 1400 and 2650 refereed papers in the past decade, respectively, with the
scientific output continuing to increase well after the completion of these surveys.
Publicly accessible data archives can multiply the scientific impact of a facility or mission⎯for a
fraction of the capital and operating costs of those facilities or missions. The data explosion and the longterm
need for the ability to cross-correlate enormous datasets require archival data preservation beyond
the life of projects and the development of new analysis and data mining tools. The establishment over
the past decade of a National Virtual Observatory, a top recommendation of the last decadal survey and
part of an International Virtual Observatory initiative, has produced widely accepted standards for data
formatting, curation, and the infrastructure of a common user interface. These standards have the
potential to substantially enhance the collective value of archival datasets.
NASA has regarded data handling and archiving as an integral part of space missions. It has
established a network of data centers to host data from their missions, and a National Academies report 9
9 Portals to the universe: The NASA Astronomy Science Centers, National Academies Press, Washington DC,
2007. This report emphasizes the role of NASA archives in allowing astronomers to examine data on a particular
target set across a range of wavelengths: “Not only are the archives the keepers of the raw observations, but they
also provide direct access to calibrated versions of their data products, with online documentation and searchable
databases linked to the literature. This “shrink-wrapped” feature of modern archives makes it easier for astronomers
to combine data across various subdisciplines, a task that would have been difficult even a few years ago when all
astronomers had their own sets of tools and did most of the data reduction themselves.”
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