Once technical and financial difficulties are beaten, the James Webb Space Telescope will collect data about galaxy, star, and planetary system formation, and interstellar dust. “Nearly all the construction contracts are signed for JWST and we’re now working on the detailed design plans,” says John Mather, the telescope’s project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland (see Physics Today, November 2002, page 30).

NASA expects to decide this month which type of mirror to use for observing at wavelengths of 1–5 microns. The choice is between a lightweight beryllium-based mirror, which has good thermal and stiffness properties, and a heavier glass-based mirror, which is cheaper and easier to fabricate. The telescope will be launched from a European Ariane V rocket, which will save NASA roughly $100 million.

Over the past eight years, JWST’s budget has ballooned from $600 million to $2.5 billion. Although NASA officials...

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