Scientific Method / Science & Exploration

What’s after the Hubble space telescope? Possibly nothing

The House Appropriations Committee is considering a budget that would kill …

As negotiations over the US debt limit continue, potential cutbacks to a huge range of programs may come as part of any deal. But in the background, regular budget work has gone ahead, and on Wednesday that work produced a shock for NASA in the form of a 10 percent budget cut. Also on the chopping block: the space-based observatory expected to replace the Hubble, the James Webb Space Telescope (JWST).

The JWST is meant to provide a window into an area of the spectrum that the Hubble couldn't view. The segment of the infrared it was designed to image will include the light from the earliest galaxies, allowing scientists to get an unprecedented view of the dynamics of the universe as the first large-scale structures emerged in the aftermath of the Big Bang.

Unfortunately, imaging in the infrared dictated a few design complications: the observatory would need a massive sunscreen to allow it to cool sufficiently so that the hardware itself wouldn't generate an infrared signal. It would also have to sit far enough from the Earth's infrared sources that a servicing mission would be overwhelmingly unlikely during its lifetime.

That means those enormous sunscreens would have to unfurl themselves in orbit, but that's not the only bit of self-assembly required. To image the most distant objects in the universe, the JWST would have the largest mirror ever put in space, built from a set of hexagonal cells that would have to be positioned precisely in order to form an appropriately shaped mirror—all of it done after launch, and without human intervention. Developing all this technology, and ensuring that the astronomy community could image everything it wants to see, required an extensive period of tech development and testing.

That development time, combined with management issues, eventually left the JWST behind schedule and over budget. Instead of being ready for launch shortly after we might expect the Hubble to start degrading due to a lack of service missions, the JWST won't launch until 2018 at the earliest. It will also require well over a billion dollars of extra spending. Given that NASA was already strapped for cash—witness its significant revisions to future manned missions—coming up with the extra cash would either require painful cutbacks elsewhere or an influx of new cash.

Instead of a budget increase, the House Appropriations Committee is now considering a 2012 budget that would see NASA's budget drop by $1.6 billion next year; the Obama administration had requested a slight increase. The proposed budget would explicitly kill the JWST, leaving NASA without a new, updated observatory for the indefinite future.

This budget is still a long way from becoming law, so there's a chance that the funding will be restored during future negotiations. But given the large number of programs that appear to be on the chopping block, a billion dollar commitment to NASA seems like the JWST's most significant hurdle yet.

Listing image by NASA

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