This award will be used to undertake a Technology Development Program (TDP) for the Square Kilometer Array (SKA). The SKA is a global program to design and build a new generation radio telescope to operate at meter to centimeter wavelengths. The SKA will be an aperture synthesis facility wherein signals from separated antennas are combined digitally to simulate a telescope having a diameter equal to the largest antenna separation, planned to be more than 3000 km. It will operate over the frequency range from roughly 100 MHz to 10-25 GHz. The SKA will have a collecting area of order one million square meters, a sensitivity 50 times higher than the Very Large Array, and an instantaneous field of view of at least 1 square degree. It will be a powerful survey telescope with the capability to follow up individual objects with high angular and time resolution.
The SKA TDP will examine the technical feasibility and costs of the so-called Large-N/Small-D concept (LNSD, where N is number of antennas and D is the diameter of each). Activities within the TDP will tap areas of expertise in the U.S. and also complement work done outside the U.S. Some of the work will comprise unique contributions to the SKA project, while others will be achieved via collaborations within the context of international working groups. The TDP will complement a systems design and costing effort carried out as a Preparatory Study under the European Commission?s Framework Programme 7.
The Square Kilometer Array (SKA) comprises next generation instruments for radio astronomy that will be used to explore the universe in unprecedented ways. The SKA will probe the formation of galaxies that began a few hundred million years after the Big Bang occurred 13.7 billion years ago. The generation and evolution of cosmic magnetic fields will also be studied along with their role in the formation of new stars. The SKA will play a key role in testing Einstein's theory of gravity and it will allow the detection of gravitational waves --- ripples in spacetime that are produced by massive objects. The broad goals of SKA science require arrays of small antennas that are connected digitally. Much more collecting area is needed and the processing of the signals to form images and other data is a huge challenge for information technology. U.S. efforts on the SKA were organized under the U.S. SKA Consortium that included representatives from the California Institute of Technology (including the Jet Propulsion Laboratory), Cornell University (including the National Astronomy and Ionosphere Center), the Harvard-Smithsonian Center for Astrophysics, the University of Illinois, the Massachusetts Institute of Technology (including Haystack Observatory), the National Radio Astronomy Observatory, the Naval Research Laboratory, the SETI Institute, the University of California (Berkeley), the University of New Mexico, and the University of Wisconsin. The NSF-funded Technology Development Project (TDP) for the Square Kilometer Array targeted research and development in areas that are central to making construction of the SKA feasible. Primary among the work areas of the TDP was the design of a low-cost, high performance reflector antenna. No off-the-shelf antenna of the type needed was available because the requirements for radio astronomy are far more stringent than those of commercial enterprises. In parallel with the design of the main reflector antenna, work was done on high-bandwidth collector antennas and receivers. The second major area of the TDP was study and simulation of new algorithms for image formation for arrays of thousands of reflector antennas, far more than have been used in radio astronomy. The technology project was done in conjunction with the international SKA project that comprised countries all over the world and has a project office in the United Kingdom. The TDP grant supported participation of U.S. scientists and engineers in the SKA steering committee and in working groups of the international project. This allowed U.S. participants to have a significant influence on the science priorities, the technology choices, and the construction sites for the SKA. The primary site is in South Africa and a secondary site is in Australia. With the termination of the TDP in 2012, there is currently no formal participation of a U.S. group in the Square Kilometer Array project. It is hoped that this will change as soon as possible.
