prepublication copy - The Department of Astronomy & Astrophysics ...
prepublication copy - The Department of Astronomy & Astrophysics ...
prepublication copy - The Department of Astronomy & Astrophysics ...
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for a space-based planet imaging and spectros<strong>copy</strong> mission could start late in the decade in preparation<br />
for a mission start early in the 2020 decade. <strong>The</strong> committee envisions that this program can be<br />
implemented at moderate funding levels early in this decade, but that it will require augmentation over<br />
current support levels for all <strong>of</strong> these activities. From the above considerations, a budget <strong>of</strong> $4 million per<br />
year is recommended in the first several years <strong>of</strong> the decade, in addition to the generally available<br />
technology development funds. If the scientific groundwork has been laid and the design requirements for<br />
an imaging mission have become clear by the second half <strong>of</strong> this decade, a technology down-select should<br />
be made. Furthermore, mission development should be supported at an appropriate level for the mission<br />
design and scope to be well understood. Initiating this activity will require significantly greater resource<br />
levels than the early-decade mission-enabling activities described above. It is currently difficult to<br />
anticipate the developments that could justify initiating this mission-specific development program, and<br />
the committee therefore recommends that a decadal survey independent advice committee be convened<br />
mid-decade to review progress both scientifically and technically to determine the way forward, and in<br />
particular whether an increased level <strong>of</strong> support associated with mission-specific technology development<br />
should commence. In this case a notional decadal budget <strong>of</strong> $100 million is proposed. However, the level<br />
<strong>of</strong> late-decade investment required is uncertain, and the appropriate level must be determined by a decadal<br />
survey independent advice committee (DSIAC) review. It could range between the notional budget used<br />
here up to a significant (perhaps on the order $200 million) mission-specific technology program starting<br />
mid-decade.<br />
<strong>The</strong> committee’s proposed program is designed to allow a habitable-exoplanet imaging mission to<br />
be well formulated in time for consideration by the 2020 decadal survey.<br />
Priority 2 (Medium, Space). Technology Development for a 2020 Decade Mission to Probe the Epoch<br />
<strong>of</strong> Inflation<br />
Detecting the B-mode polarization pattern on the cosmic microwave background impressed by<br />
gravitational waves produced during the first few moments <strong>of</strong> the universe both would provide strong<br />
evidence for the theory <strong>of</strong> inflation that is so crucial to our understanding <strong>of</strong> how structures form, and<br />
would open a new window on exotic physics in the early universe in regimes not accessible even to the<br />
most powerful particle accelerators on Earth. Progress in measuring both the polarization and the finescale<br />
anisotropy <strong>of</strong> the cosmic microwave background radiation is proceeding rapidly with ground-based<br />
telescopes in Antarctica and Chile and space-based instruments.<br />
<strong>The</strong> recommended enhanced suborbital program, as described below, as well as missions <strong>of</strong><br />
opportunity made possible by an augmented Explorer program, will provide opportunities for substantive<br />
balloon experiments to probe the polarization signal to faint levels. NASA through the APRA program,<br />
as described below, should augment support for CMB technology development at a modest level. If the<br />
combined space and ground-based program is successful in making a positive detection <strong>of</strong> B-modes from<br />
the epoch <strong>of</strong> inflation, it is further recommended that NASA then should embark on an enhanced program<br />
<strong>of</strong> technology development, with a view to preparing a mature proposal for a dedicated space mission to<br />
study inflation through CMB observations for consideration by the 2020 decadal survey. If this<br />
observational goal is not met, then the suborbital programs and the broad technology development<br />
programs should continue to be supported at the same early-decade level with the goal <strong>of</strong> further<br />
improving detection limits.<br />
In summary, significant progress on CMB studies, including the understanding <strong>of</strong> foregrounds, is<br />
certain given the successful operation <strong>of</strong> Planck and the suborbital and ground-based facilities that are<br />
currently operating or will come online soon. A successful detection <strong>of</strong> B-modes from inflation could<br />
trigger a mid-decade shift in focus toward preparing to map them over the entire sky. In this case a<br />
notional decadal budget <strong>of</strong> $60 million is proposed. However, the level <strong>of</strong> late-decade investment<br />
required is uncertain, and the appropriate level should be studied by a decadal survey independent advice<br />
PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION<br />
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