Though the United States did not officially join the Founding Board of the Square Kilometer Array (SKA), the US does remain supportive of the project. In large part, the decision not to join the Founding Board is based on the recommendations of the most recent astronomy decadal survey performed by the National Research Council, “New Worlds, New Horizons in Astronomy and Astrophysics,” released in August 2010.
This report concluded that the combination of technical readiness and high cost risk made it unfeasible for the National Science Foundation (NSF) to invest in SKA construction during the 2010-2020 decade. NSF has accepted that conclusion and is setting a priority for SKA construction that is consistent with this conclusion and the other recommendations of the decadal survey.
Sites in South Africa and Australia have been short-listed to host the central core of the SKA telescope. If located in Australia, the SKA antennas would extend all the way to New Zealand and if located in South Africa, the SKA antennas would extend to the Indian Ocean islands.
A decision on the location of the SKA site will be made in 2012. A Site Selection Group has been established to oversee the process of evaluating the information on each candidate site. Selection of the host site for the SKA will be made with the utmost care to ensure the best possible operating environment for the telescope.
NSBP link: Vector blog: The US remains Supportive of the Square Kilometer Array project