is recommended to be split between NSF and DOE at two-thirds and one-third, respectively. The committee recommends that LSST be submitted immediately for NSF’s MREFC consideration with a view to achieving first light before the end of the decade. Independent review judged the cost and schedule risk, as well as the technical risk, to be medium low.

The top rank accorded to LSST is a result of (1) its compelling science case and capacity to address so many of the science goals of this survey and (2) its readiness for submission to the MREFC process. LSST was judged by its technical maturity, the survey’s assessment of risk, and appraised construction and operations costs. Having made considerable progress in terms of its readiness since the 2001 survey, LSST was judged as the most “ready-to-go.”

New discoveries and technical advances enable small- to medium-scale experiments and facilities that advance forefront science. A large number of compelling proposed research activities submitted to this survey were highly recommended by the Program Prioritization Panels, with costs ranging between the limits of the NSF Major Research Instrumentation and MREFC programs, $4 million to $135 million. The committee recommends a new competed program to significantly augment the current levels of NSF support for mid-scale programs. An annual funding level of $40 million per year is recommended—just over double the amount currently spent on projects in this size category through a less formal programmatic structure.

The principal rationale for the committee’s ranking of the Mid-Scale Innovations Program is the many highly promising projects for achieving diverse and timely science.

Transformative advances in optical and infrared (OIR) astronomy are now possible by building adaptive optics telescopes with roughly 10 times the collecting area and up to 80 times the near-infrared sensitivity of current facilities. These observatories will have enormous impact across a large swath of science and will greatly enhance the research that is possible with several other telescopes, especially JWST, the Atacama Large Millimeter/submillimeter Array (ALMA), and LSST. A federal investment to provide access for the entire U.S. astronomy and astrophysics community to an optical-infrared 30-meter-class adaptive optics telescope is strongly recommended. Two U.S.-led projects, the Giant Magellan Telescope (GMT) and the Thirty Meter Telescope (TMT), are being developed by international collaborations led by U.S. private consortia. The committee recommends that a choice between