he next-generation radio telescope, the Square Kilometer Array (SKA)
is scheduled for operation in 2020. The SKA is an international effort, with 34 institutions in 15 countries collaborating on research and technology development for the final product.
The SKA will follow on the heels of LOFAR, PAST, and MWA — three radio arrays being developed and tested — with improved sensitivity. The main science goal behind the SKA — to search for neutral hydrogen's 21-centimeter line, pinning down when the universe reionized — will need the sensitivity.
The SKA will operate over a frequency range of 100MHz to 25GHz, enabling astronomers to make a variety of deep observations.
The SKA will have — as its name implies — a square kilometer collecting area, distributed among 30 to 100 "stations." Each station will be between 30 and 300 meters in diameter. (For comparison, the Arecibo Telescope in Puerto Rico has a diameter of 305 meters.)
The SKA will have stations spiraling away from a dense core. Twenty percent of the collecting area must be within a 1 kilometer-diameter circle, 50 percent within 5 km, and 75 percent within 150 km. The outer edge of the entire collecting area must be at least 3,000 km away.