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Mid-Scale Project Descriptions
This survey received 29 proposals that would be eligible for competition, with an aggregate
construction or fabrication cost of roughly $1.2 billion. The Program Prioritization Panels recommended
very highly a subset of these, with rough total cost of $400 million. It is not appropriate for this survey to
make priority assessments for activities that would compete in a peer-reviewed program. However, the
case for such a program line is best made by describing selected examples, as is done below in
alphabetical order and in Table 7.1. Not all of them will be funded, but the funding recommended would
be sufficient to proceed with many of them, as well as several excellent new proposals that will surely be
submitted in response to a general solicitation. These proposals are grouped into three cost categories
based on submitted descriptions and not independent committee review. It is important that the Mid-Scale
Innovations Program itself maintain a balance between large and small projects.
$40 MILLION TO $120 MILLION RANGE
Big Baryon Oscillation Spectroscopic Survey: The Big Baryon Oscillation Spectroscopic Survey
(BigBOSS) would utilize the Kitt Peak National Observatory 4-meter Mayall telescope and a newly built
optical spectrograph capable of measuring over 5000 spectra simultaneously over a 3 degree field-ofview.
The science goal is understanding the acceleration of the universe by observing the distributions of
30 million galaxies and a million quasars. These data will also address important questions concerning the
formation and evolution of galaxies, black holes, and the intergalactic medium.
Frequency Agile Solar Radiotelescope: The Frequency Agile Solar Radiotelescope (FASR) consists of
three arrays of radio telescopes operating across a broad range of frequency (from 50 Mega Hertz to 20
Giga Hertz). Its overall scientific program is to conduct time-domain mapping of the solar atmosphere in
a campaign mode, delivering data products to the solar physics community. This will be used to study the
nature and evolution of the sun’s magnetic field, to understand solar flares, improve our ability to predict
‘space weather’ caused by solar activity, and to better understand the quiet sun.
Hydrogen Epoch of Reionization Array: The Hydrogen Epoch of Reionization Array (HERA) is a multistage
project in radio astronomy to understand how hydrogen is ionized after the first stars start to shine.
The first phase (HERA I) is under way and will demonstrate the feasibility of the technical approach. The
second phase (HERA II) would serve as a pathfinder for an eventual world-wide effort in the following
decade to construct a facility with a total collecting area of a square kilometer and the power to make
detailed maps of this critical epoch in the history of the universe. Proceeding with HERA II should be
subject to HERA I meeting stringent performance requirements in its ability to achieve system calibration
and the removal of cosmic foreground emission.
North American Nanohertz Observatory for Gravitational Waves: The North American Nanohertz
Observatory for Gravitational Waves (NANOGrav) would utilize the naturally occurring population of
precision astronomical ‘clocks’ called pulsars (rapidly spinning neutron stars) to detect very low
frequency gravitational waves using upgraded capabilities of the existing Arecibo and Robert Byrd radio
telescopes. The pulsar timing should also be able to detect the formation and collision of massive black
holes with signals at periods of months to several years. This facility could be able to detect relic
gravitational waves from the very early universe (which is otherwise inaccessible to direct observations).
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