COMMENT delay. The NSF should continue to support the operation of existing radio-astronomy facilities in the United States, maintaining core capabilities that will also be necessary as test-beds for SKA technology in the com- ing decade. The US$10 million to $15 million per year needed to retain Green Bank and the VLBA is small relative to the billions already invested in US radio astronomy, which draws upon one-third of the NSF’s annual $230 mil- lion astronomy budget. THE WAY FORWARD NSF funding for SKA development should SKA ORG./TDP/DRAO/SWINBURNE ASTRONOMY PRODUCTIONS ASTRONOMY SKA ORG./TDP/DRAO/SWINBURNE be re-established. Even low initial levels (around $100,000 per year) would support planning activities, travel to meetings and some basic technology research. US facili- Artist’s impression of part of the Square Kilometre Array, which will be sited in South Africa and Australia. ties and university astronomy groups should together develop a strategy for participating in SKA planning and prototyping. By 2015, the United States should rejoin the SKA as a The United States full partner. In the next 1–2 years, Phil Diamond and the consortium should decide the techni- must rejoin the SKA cal requirements for the SKA (including frequency range, field of view, angular reso- Plans for the radio-telescope array must be firmed up lution and sensitivity), and should clearly define the technology developments neces- to help Americans get back on board and ensure its sary for a realizable instrument. This will success, say Anthony J. Beasley and Ethan J. Schreier. be tricky because the ambitious goals of the SKA hinge on continual ‘Moore’s law’ improvements in digital technologies. he world’s most powerful astronomi- supporting — and so potentially close — the Components available now will be obso- cal instrument is currently being Green Bank Telescope and the Very Long lete by the time the telescope comes online, built in South Africa and Australia. Baseline Array (VLBA), both state-of-the- so a gradual updating process needs to be TA growing consortium of countries, soon to art and cost-effective telescopes with which worked into the plan. Planners must project be marshalled by incoming director-general SKA technologies could be evaluated. what technologies will become available in Phil Diamond, is laying the foundation for Our experience in building large telescopes the next decade, and pick those that are fea- some unique science. When it comes online on the ground and in space leads us to believe sible within a reasonable funding envelope. next decade, the Square Kilometre Array that these decisions are short-sighted. They Progress must be synchronized with pro- (SKA) will observe diffuse hydrogen ionized leave US astronomers and engineers unable jections of funding, so that partner contribu- by the first stars and galaxies, use pulsars to to contribute to the SKA design or to partici- tions can be integrated steadily. To maintain explore general relativity, and detect the pate in its science. The global astronomy com- project momentum, detailed design and imprints of dark energy on the distribution munity will press ahead without the United development efforts should be paced and not of matter in the Universe. States. But without US scientific and technical completed long before construction money There is one country notable by its absence input, and the ability to test SKA technologies becomes available. in this endeavour: the United States. And its at our facilities, the array’s development will With US involvement and careful plan- absence threatens to hinder the SKA’s pursuit be slowed down by many years. ning, the global radio-astronomy commu- of its scientific goals. After nearly 20 years A lack of clarity on technical details and nity can drive an evolutionary path towards of participation, US astronomers last year costs were the main criticisms of the SKA in the SKA, one that builds on current invest- dropped out of the SKA collaboration as the the US astronomy community’s 2010 dec- ments while enabling major discoveries as result of disillusionment with the project’s adal survey (go.nature.com/4qyqle), which we advance. ■ planning process and budget pressure from considered the project scientifically exciting the National Science Foundation (NSF). but only partly defined. We agree. Satisfy- Anthony J. Beasley is director of the This cannot be allowed to continue: the ing all the telescope’s ambitious goals will National Radio Astronomy Observatory. United States must eventually rejoin the require several different types of technology Ethan J. Schreier is president of Associated SKA. We call on the NSF to plan for a US (such as receiving dishes, dipoles and tiles) Universities Incorporated. role in the SKA, and we urge the SKA con- and the consortium has yet to decide how to e-mail: [email protected] sortium and Phil Diamond to review the adapt and integrate them. Participation of programme’s goals and produce a realistic US astronomers will be crucial in the firm- plan for achieving them. ing up of those plans. CORRECTION In late 2011, the NSF ceased to fund any The scientific community recognizes that The article ‘Beyond the Higgs’ (Nature US participation in SKA development. This seed funding and development work towards 488, 581–582; 2012) located the RENO blow could be compounded if the NSF the next generation of facilities is important, experiment in Seoul instead of Yonggwang. adopts its panel’s recommendation to stop and that gaps in funding only add cost and 20 SEPTEMBER 2012 | VOL 489 | NATURE | 363 © 2012 Macmillan Publishers Limited. 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