Initial Public Statement On The Report Of The NSF’s Astronomy Portfolio Review Committee
Associated Universities Inc. (AUI) and the National Radio Astronomy
Observatory (NRAO) have made a preliminary examination of the report
released today from the National Science Foundation (NSF) Astronomy
Portfolio Review Committee (PRC). Among the recommendations of that
report are that the NSF’s Green Bank Telescope (GBT) and Very Long
Baseline Array (VLBA) be fully divested from the NSF Astronomy
Division’s portfolio of research facilities in the next five years,
with no further funding from the Astronomy Division.
AUI and NRAO recognize and acknowledge the need to retire obsolete
facilities to make way for the state-of-the-art. However, both the GBT
and the VLBA are the state-of-the-art, and have crucial capabilities
that cannot be provided by other facilities. Separately the two
telescopes provide unparalleled scientific access to the universe. When
their information is combined, the instruments provide the highest
sensitivity and resolution available for any astronomical instrument in
The Green Bank Telescope
The GBT, located in Green Bank, West Virginia, is the largest and most
capable fully steerable single-dish radio telescope in the world. It is
a cutting-edge research instrument at the height of its powers, and it
is continually growing more capable through the introduction of low-cost
upgrades to its light detecting and processing electronics. It is the
only world-class astronomical telescope in the eastern United States and
has been in full scientific operation for less than 10 years.
Weighing sixteen million pounds, and able to precisely point its 2.3
acres of light-collecting surface area anywhere within all but the
southernmost 15 percent of the celestial sphere, the $95 million GBT is
an engineering and scientific marvel unlikely to be recreated, much less
surpassed, by American astronomy for decades to come. Indeed,
astronomers in other parts of the world are at work trying to build
their own telescopes of similar concept and design to the GBT, but none
of those telescopes will exceed its performance.
The GBT is used by astronomers and students around the world for
important research. It is a powerful tool for searching out the
molecular building blocks of life in space, for probing the nature of
matter at extreme densities, for mapping diffuse clouds of intergalactic
gas that are invisible to other telescopes, for finding beacons in space
that can serve as mileposts for calibrating our understanding of cosmic
distance scales and the characteristics of dark energy, for detecting
gravity waves first predicted by Einstein, and for pioneering and
experimenting with new observational tools and techniques.
The GBT’s annual cost of operation is about 0.7 percent of the annual
federal budget for astronomy and astrophysics, but the cost of replacing
it, once it’s gone, would be enormous. In an era of constrained
budgets, leveraging and improving the existing state-of-the-art through
low-cost technology upgrades (the development of which often involves
students) is a cost-effective way to keep science moving forward.
Today’s GBT, because of such improvements, is 10 to 100 times more
powerful than the original telescope, which entered full science
operations in 2003. With small upgrades, the GBT has substantial
potential to continue on this upward arc of increasing scientific power.
The Very Long Baseline Array
Comprising ten radio dish antennas distributed across 5,351 miles from
Hawaii to the U.S. Virgin Islands — a span equal to two-thirds
Earth’s diameter — the VLBA is astronomy’s sharpest tool, the
world’s largest, highest-resolution dedicated telescope (of any kind).
It is capable of creating detailed images of portions of the sky so tiny
that they are covered by but one pixel of a Hubble Space Telescope
Commissioned in 1993, the VLBA is now up to 5,000 times more powerful
than it was originally, thanks to new state-of-the-art receivers and a
data processing supercomputer installed in 2010.
The VLBA is a critical tool for all of astronomy, including research
conducted by astronomers who may never directly use the telescope,
because knowing distances in space accurately is essential for figuring
out the mass, makeup, movement, and evolution of cosmic objects. All of
astrophysics hangs on this.
With the VLBA, astronomers can directly measure the distances to and
rotation rates of galaxies, create the most accurate map ever of our own
Milky Way Galaxy, directly measure cosmological distances to distant
masers (helping to characterize dark energy), trace the movements of
black holes and pulsars to learn their history and future, predict if
and when galaxies will collide (including the Andromeda Galaxy with our
Milky Way), pinpoint the exact centers of planets in our solar system
and the most accurate distances to stars, and develop the celestial
reference grid used by other telescopes.
Such direct distance and position measurements do not depend upon the
assumptions that underlie other distance measurement techniques in
Beyond the many manifestations of its value as astronomy’s most
accurate distance and position measuring machine, the VLBA investigates
many intrinsically fascinating questions in astronomy, including the
growth and feeding of supermassive black holes, the ejection of
supercharged gas from galactic cores, and the expansion of supernova
shock waves. Closer to home, the VLBA can uniquely track the spin rate
of nearby asteroids; how asteroids’ spin influences their paths
through space (paths that could disastrously intersect with Earth), and
cannot be measured by other telescopes. The VLBA is even used to track
the movements of Earth’s crust; this is done by observing distant
quasars, and it has implications for fields ranging from GPS navigation
to climate change.
The VLBA’s annual operation budget is miniscule, less than a half of a
percent of the 2012 federal astrophysics budget across agencies. To
build the VLBA from scratch today would cost hundreds of millions of
The Portfolio Review Process
AUI and NRAO believe in prudent planning to ensure the ongoing success
of the U.S. astronomy and astrophysics program. However, given the
multi-agency nature of federal support for this field, it is essential
that important national scientific assets be evaluated in the context of
the total investments made in optical, radio, and solar astronomy.
In an era of fiscal constraint, it is even more important to leverage
already existing world-leading facilities to maximize the benefit to
science and taxpayers while enabling future advances. In radio
astronomy, which is primarily supported by the NSF, the GBT and VLBA
comprise the best telescopes of their kind that the world has to offer.
As ground-based telescopes, they are extremely cost-effective. These
facilities have multiple federal users and sponsors as well as critical
state stakeholders who rely upon them.
AUI and NRAO believe that optimizing the United States’ astronomy
portfolio should involve considerations beyond just the question of what
can be cut from a particular funding agency’s budget to make room for
something new in that same agency’s budget. We believe that any
recommendations ultimately embraced by NSF should seek to:
– Ensure that students have ready access to training and
instrumentation opportunities at world-class, U.S.-based facilities
– Provide a strong and broadly-based U.S. program that complements and
reinforces our shared-access international facilities
– Preserve unique and irreplaceable national research infrastructure
that maintains U.S. leadership in optical, radio, and solar
None of these goals will be advanced by removing the GBT and VLBA from
the portfolio of telescopes funded via the NSF; indeed, they will be
AUI and NRAO encourage the NSF to work with its other federal agency
counterparts to consider a more balanced approach with additional
funding scenarios for the entire U.S. federal astronomy portfolio.
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