Square Kilometre Array: a concept design for Phase 1

The SKA at mid and low frequencies will be constructed in two distinct phases, the first being a subset of the second. This document defines the main scientific goals and baseline technical concept for the SKA Phase 1 (SKA_1). The major science goals for SKA_1 will be to study the history and role of neutral Hydrogen in the Universe from the dark ages to the present-day, and to employ pulsars as probes of fundamental physics. The baseline technical concept of SKA_1 will include a sparse aperture array operating at frequencies up to 450 MHz, and an array of dishes, initially operating at frequencies up to 3 GHz but capable of 10 GHz in terms of antenna surface accuracy. An associated Advanced Instrumentation Program (AIP) allows further development of new technologies currently under investigation. Construction will take place in 2016-2019 at a total capital cost of 350M\texteuro, including an element for contingency. The cost estimates of the SKA_1 telescope are now the subject of a more detailed and thorough costing exercise led by the SKA Project Development Office (SPDO). The 350 M\texteuro total for SKA_1 is a cost-constrained cap; an additional contingency is to reduce the overall scope of the project. The design of the SKA_1 is expected to evolve as the major cost estimates are refined, in particular the infrastructure costs at the two sites. The SKA_1 facility will represent a major step forward in terms of sensitivity, survey speed, image fidelity, temporal resolution and field-of-view. It will open up new areas of discovery space and demonstrate the science and technology underpinning the SKA Phase 2 (SKA_2).