Webb Telescope Approaches Launch, With an Eye Toward Cosmic Origins

There are only a few times in the history of a species when it gains the know-how, the audacity and the tools to greatly advance the interrogation of its origins. Humanity is at such a moment, astronomers say.

According to the tale that they have been telling themselves (and the rest of us) for the last few decades, the first stars flickered on when the universe was about 100 million years old.

They burned hard and died fast in spectacular supernova explosions, dispelling the gloomy fog of gas left over from the primordial fireworks known as the Big Bang 13.8 billion years ago. From those sparks came all that we care about in the universe — the long, ongoing chain of cosmic evolution that has produced everything from galaxies and planets to microbes and us.

But is that story right?

The tools to address that question and more are at hand. Sitting in a spaceport in French Guiana, wrapped like a butterfly in a chrysalis of technology, ambition, metal and wires, is the biggest, most powerful and, at $10 billion, most expensive telescope ever to be launched into space: the James Webb Space Telescope. Its job is to look boldly back in time at the first stars and galaxies.

“We’re looking for the first things to come out of the Big Bang,” said John Mather of the Goddard Space Flight Center in Green Belt, Md., the chief scientist for the telescope. Or, as he likes to ask: “How did we get here from the Big Bang?”

If all goes well — always a dubious prospect in the space business — the telescope will be loaded onto an Ariane 5 rocket and, on the morning of Dec. 24, blast off on a million-mile journey to a spot beyond the moon where gravitational forces commingle to create a stable orbit around the sun.

Over the next 29 days on its way up, the chrysalis will unfold into a telescope in a series of movements more complicated than anything ever attempted in space, with 344 “single points of failure,” in NASA lingo, and far from the help of any astronaut or robot should things become snarled. “Six months of high anxiety,” engineers and astronomers call it.

First, antennas will pop out and aim at Earth, enabling communication. Then the scaffolding for a sunscreen the size of a tennis court will open, followed by the sunscreen itself, made of five thin sheets of a plastic called Kapton.

Finally, 18 gold-plated beryllium hexagons will snap into place to form a segmented mirror 6.5 meters, or 21 feet, across. By then, the telescope will have reached its destination, a point called L2, floating on its sun shield and aimed at eternity.

Astronomers will then spend six months tweaking, testing and calibrating their new eye on the cosmos.

Looking back at the fog

The James Webb Space Telescope, named after the NASA administrator who led the agency through the Apollo years, is a collaboration between NASA, the Canadian Space Agency and the European Space Agency. Its official mission is to explore a realm of cosmic history that was inaccessible to Hubble and every telescope before it.

“We are all here because of these stars and galaxies,” said Alan Dressler of the Carnegie Observatories in Pasadena, Calif.

That mission requires the Webb to be tuned to…