Monday, July 25, 2011

Oh what a tangled Webb

I wrote here recently about the Square Kilometer Array, a giant internationally-sponsored radio telescope that seems to have a fair chance of actually being built. More problematic is the James Webb Space Telescope, an infrared-optimized space telescope that is designed to be America's successor to the aging Hubble. If it gets off the ground, the Webb will have a mirror 6.5 meters in diameter, three times the diameter of the Hubble's. It will be best adapted for exploring the very dawn of the universe, when the first stars and galaxies were forming.

Unfortunately, the initial cost estimate of $1.6 billion has ballooned to more than $6.5 billion -- and counting -- soaking up dollars that would have supported other astronomical research. The journal Nature called the Webb "the telescope that ate astronomy." Not surprisingly, the cost-conscious, Republican-dominated House has an ax aimed at the project.

Here's the tricky thing.

The Hubble orbits several hundred miles above the Earth, where it could be serviced by Shuttle-borne astronauts, something that turned out to be essential when the original optics were found to be faulty. The Webb will hover a million miles from the Earth, at one of the so-called Lagrangian points, a place where it can maintain a fixed relationship with the Earth and Sun. Like the Earth, it will orbit the Sun once each year, although a million miles farther out into space. This will make it possible to shield the scope from heat radiation of Earth, Moon and Sun. The scope must also be cooled so that its own heat doesn't interfere with its operation.

No astronauts will be available to fix any problems that arise. It has to work right the first time. The Webb is a hugely complex instrument. It must be "dropped on a dime" at its Lagrangian destination and its mirror and heat-shield must be deployed in space -- nail-biting tasks for an instrument that may end up costing $10 billion.

Will the Webb telescope survive? Is a glimpse at the origins of the universe worth rolling the dice on a $10 billion pot? Should the U.S. turn the whole thing over to the Chinese and be done with it? Are the glory days of American space exploration behind us?

Just how important is a look 13 billion years back in time to the nearly half of Americans who believe the universe is less that 10,000 years old?