Throwing money into space

A shiny new telescope is crowding out NASA's other science missions. THE Hubble space telescope, an orbiting observatory launched in 1990 by NASA, America's space agency, has been one of that agency's most successful missions since the Apollo moon shots in the 1960s and 1970s. It has produced a string of scientific achievements: confirming that most galaxies have a black hole in the middle; providing a front-row seat for the collision, in 1994, of a comet with the planet Jupiter; and helping to uncover the strange fact that the expansion of the universe seems to be accelerating. But beyond the science, it has also been a public-relations hit. Its beautiful images have introduced a generation to the wonders of astronomy. So in 2002, when the agency considered plans for a successor that would study the universe in infra-red, rather than visible light, would be ready to fly in 2010 and would cost just $2.5 billion, saying "yes" was easy.

Nine years later, NASA is regretting that decision. The James Webb space telescope (JWST), as the new machine is called, is still in the workshop, and its launch date has been set back repeatedly (2018 is the latest official estimate).  Its cost has gone up to $8.8 billion, a figure that, if history is any guide, could rise still further. Which would be embarrassing at the best of times, but with public-spending cuts looming and NASA's budget flat for the foreseeable future, it is causing real strains.

In July, irritated by the JWST's rising costs, the House of Representatives tried to cut $1.9 billion from NASA's budget for next year, in an attempt to have the project cancelled. On November 1st, after lobbying from the telescope's defenders (particularly the American Astronomical Society), the Senate passed a bill that restored the telescope's funding. But it is not just politicians that are restive. Astronomers have long worried that the ballooning costs of the telescope would affect NASA's other science projects. Officially, the space agency will say only that other missions will be delayed, but there are fears that some could be cut completely. One potential sacrifice is WFIRST, an infra-red space telescope intended for launch in 2020. This is designed to probe the nature of "dark energy", which is thought to be responsible for the quickening expansion of the universe that Hubble helped bring to the world's attention. A string of other, smaller projects could suffer as well.

The telescope's advocates say junking it now would be a false economy. Most of the hardware has already been built, so cancelling it, they argue, would mean throwing all that away. And they play on fears that America is in danger of losing its pre-eminence in high-budget "big science", following the closure earlier this year of the Illinois-based Tevatron, the second-most-powerful particle accelerator in the world. The JWST, if it does eventually fly, would surely do some spectacular science. The size of its mirror-25 square meters, as against Hubble's 4.5-and the location of its orbit far from the reflected light of Earth will allow it to study some of the earliest (and therefore faintest) events in the universe, including the formation of the first galaxies. It will also help with the search for extrasolar planets.

Hubble, of course, was also late-and around $2 billion over budget. It was lampooned after its launch when a wonky mirror meant that its images were blurred almost to the point of uselessness, and a mission by the Space Shuttle to fix the problem cost hundreds of millions of dollars. Given its subsequent record, few now begrudge the cost. With all that in mind, NASA will press on with the JWST, at least for now. All that remains for America's astronomers to do is pray that their favorite mission is not one of those delayed, or even cancelled, to keep the new telescope on track.