Space telescope is worth the effort

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Your sensationalist headline 'The telescope that ate astronomy' could more appropriately have highlighted the promise of NASA's James Webb Space Telescope (JWST) for astronomy's future (Nature 467, 1028–1030; 2010).

No facilities exist on or off this planet — or are called for in the recent US decadal survey of astronomy and astrophysics — for finding the first galaxies or for detecting liquid water on habitable planets around other stars. These capabilities have been part of the JWST science plan since its inception.

Such transformative science is why NASA, the European Space Agency and the Canadian Space Agency took on the challenge of building a telescope of comparable scale to the ground-based W. M. Keck telescopes or one of Europe's Very Large Telescopes. This meant reducing the JWST's mass by almost two orders of magnitude compared with a Keck telescope, cooling it to −313 °C and folding it to fit inside an Ariane 5 spacecraft for deployment 1.5 million kilometres from Earth.

Building the JWST has required the manufacture of 18 1.3-metre beryllium mirrors able to hold their shapes to better than 20 nanometres at cryogenic temperatures, and of a deployable gossamer sunshield the size of a tennis court.

It was equally challenging to build the Hubble Space Telescope. But it was worth it: Hubble has revolutionized our understanding of the Universe, inspired generations of school children with its breathtaking images and supported a community of 8,000 astronomers worldwide. Likewise, the efforts of today's space scientists are creating a revolutionary telescope for the next generation of scientists and engineers.

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Mountain, M., Grunsfeld, J. & Hammel, H. Space telescope is worth the effort. Nature 468, 508 (2010) doi:10.1038/468508c

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