NASA Delays James Webb Telescope Launch Date, Again

NASA Delays James Webb Telescope Launch Date, Again

NASA Delays James Webb Telescope Launch Date, Again

NASA Delays James Webb Telescope Launch Date, Again

After years of budget overruns, testing problems and political difficulties, NASA’s next great telescope has been delayed again, the space agency announced Thursday. The James Webb Space Telescope, which was proceeding toward a launch date of March 2021, will now be launched no sooner than Oct. 31, 2021.

In a news conference Thursday, NASA officials blamed the delay on disruptions caused by the coronavirus pandemic and on schedule reviews that started last winter. “Mission success is critical, but team safety is our highest priority,” said Stephen Jurczyk, NASA’s associate administrator.

NASA said the delay would not add to the project’s overall cost, which was capped at $8.8 billion by Congress a few years ago, because the program had reserves in its budget. “Based on current projections, the program expects to complete the remaining work within the new schedule without requiring additional funds,” said Gregory Robinson, the program director for Webb at NASA.

Nor would it impact the ability of the Webb telescope to work with the Hubble Space Telescope, which the agency says will now last into the 2030s.

The telescope, named after James Webb, who led the space agency in the 1960s, is the long-awaited successor to Hubble. “Webb is designed to build upon the incredible legacies of the Hubble and Spitzer space telescopes by observing the infrared universe and exploring every phase of cosmic history,” said Eric Smith, Webb’s program scientist.

Seven times larger than the Hubble in light-gathering ability, the Webb was designed to see farther out in space and deeper into the past of the universe. It may solve mysteries about how and when the first stars and galaxies emerged some 13 billion years ago in the smoky aftermath of the Big Bang.

The telescope’s main mirror is 6.5 meters in diameter, or just over 21 feet, compared with 2.4 meters for the Hubble. Its mission is to explore a realm of cosmic history stretching from about 150 million to one billion years after time began — known as the reionization epoch, when bright and violent new stars and the searing radiation from quasars were burning away a gloomy fog of hydrogen gas that prevailed at the end of the Big Bang.

Astronomers theorize that during that epoch, an initial generation of stars made purely of hydrogen and helium — the elements created during the Big Bang — burned ferociously and exploded apocalyptically, jump-starting the seeding of the cosmos with progressively more diverse materials. But nobody has ever seen any so-called Population 3 stars, as those first stars are known. They don’t exist in the modern universe. Astronomers have to hunt them in the dim past.

That ambition requires the Webb to be tuned to a different kind of light than our eyes or the Hubble can see. Because the expansion of the cosmos is rushing those earliest stars and galaxies away from us so fast, their light is “red-shifted” to longer wavelengths, the way the siren from an ambulance shifts to a lower register as it passes by.

So blue light from an infant galaxy bursting with bright spanking new stars way back then has been stretched, by the time it reaches us 13 billion years later, to invisible infrared wavelengths, or heat radiation which Webb is equipped to detect.

It also turns out that infrared emanations are the best way to study exoplanets, the worlds beyond our own solar system that have been discovered in the thousands by observatories in space and on the ground since the Webb telescope was conceived.

In order to see those infrared colors, however, the telescope has to be very cold — less than 45 degrees Fahrenheit above absolute zero — so that its own heat does not swamp the heat from outer space. Once in space, the telescope will unfold an umbrella the size of a tennis court to keep the sun off it. The telescope, marooned in permanent shade a million miles beyond the moon, will experience an infinite cold soak.

The sun shield consists of five thin, kite-shaped layers of a material called Kapton. Much too big to fit into a rocket, the shield, as well as the telescope mirror, will have be launched folded up, and testing the shield on Earth has proved devilishly difficult. It will then be unfolded in space over six months in a series of 180 maneuvers that look in computer animations like a cross between a parachute opening and a swimming pool cover going into place.

Or at least that is the plan. That whole process will amount to what the engineers call “six months of high anxiety.” In space, nobody will be there with a wrench to help. Which means it will be a long nervous wait for the next set of cosmic baby pictures.


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