The James Webb Space Telescope’s Mission Is Unfolding As Expected

When it comes to superstitions, NASA and baseball see the world in different ways. It’s one of baseball’s unwritten rules that when a pitcher is throwing a no-hitter through, say, seven innings, you never, ever mention it out loud. To speak of it is to jinx it, and likelier than not, you’ll get clobbered in the eighth.

NASA, clearly, takes a different approach. In the 13 days since the Christmas morning launch of the James Webb Space Telescope—the most powerful and complex cosmic observatory ever built—the space agency has been tossing successful inning after successful inning, getting the telescope unfolded, aligned, and powered-up, and keeping it on course to its destination 1.6 million km (1 million mi.) away from Earth at a gravitationally stable spot called L2, where it will station-keep for the next decade, peering deeper into the universe than any telescope ever has before. The space agency has been none too shy about talking up its successes, even hosting a sort of Webb dashboard, with regular updates on just where in space the telescope is and what milestones it has passed.

Such early, if cautious, enthusiasm is understandable, since the challenges Webb faced before launch were daunting. The $10 billion telescope—which consists principally of an 18-segment, 6.5 m (21.3 ft) mirror and a sun shield the size of a tennis court—had to be folded up small enough to fit in the 5 m (16 ft) payload bay of the Ariane 5 rocket that launched it, then released into space and unfolded in a process that one Webb team leader described as “origami in reverse.” That was never going to be easy. Hundreds of hinges, pulleys, actuators, and more have to work in a perfect synchrony, overcoming 344 so-called “single-point failures”—each a solitary breakdown that, all by itself, could spell the end of the mission.

Far and away, the most challenging step was unfolding the sun shield, a delicate structure that consists of five layers of kapton, a foil-like film—each thinner than a human hair—that protects the mirror from the heat of the sun and allows it to operate at the ultra-cold temperatures necessary to observe space in the infrared wavelength, which is the ability that gives Webb its exquisite visual acuityคำพูดจาก เว็บดีฝากถอนปลอดภัย. That step was successfully completed on Jan. 4, and NASA was ready with a celebratory tweet.

“This is it,” the space agency crowed, “we’ve just wrapped up one of the most challenging steps of our journey to #UnfoldTheUniverse. With all five layers of sunshield tensioning complete, about 75% of our 344 single-point failures have been retired!”

Webb program director Gregory Robinson was no less enthusiastic in a later conversation with TIME, if a little bit more measured. “Certainly, I would say the sunshield deployment and tensioning was probably the single highest risk,” he says. “There are many others, but we came through that one pretty good.”

The next big step came the very next day, when the telescope’s secondary mirror—a much smaller .74 m (2.4 ft.) reflector—was deployed. The mirror is positioned on three seven-meter (25 ft) long struts and will reflect the infrared signatures captured by the main mirror and direct them into the telescope’s instruments.

“The world’s most sophisticated tripod has deployed,” said Lee Feinberg, a Webb project manager, in a statement. “Webb’s secondary mirror had to deploy in microgravity, and in extremely cold temperatures, and it ultimately had to work the first time without error. It also had to deploy, position, and lock itself into place to a tolerance of about one and a half millimeters.”คำพูดจาก สล็อตเว็บตรง

After the secondary mirror comes the deployment of the main mirror—which is currently still folded like a table with leaves—a process that will begin today or Saturday. Following that will be a much slower, 10-day exercise in which each of the mirror’s 18 hexagonal segments is angled and adjusted in seven different axes—up, down, left, right, in, out and diagonally—to bring the overall mirror into focus. That one will take some patience.

“That’s a slow process,” says Robinson. “It’s almost like watching grass grow—though it’s some pretty grass when it’s done right.”

Still to come online is a suite of onboard sensing instruments, most importantly, the near-infrared camera (NIRCam), the spacecraft’s primary imager; and its mass spectrometer, which will allow Webb to analyze the chemistry not just of objects deep in the universe, but also the atmospheres of exoplanets in our own galaxy, looking for chemical signatures of methane, oxygen, carbon dioxide and more, which could provide clues to whether the planets are habitable—or even inhabited.

“A lot of the detail that we don’t get today on the elements of these different planets, Webb will be able to provide,” says Robinson. “That will open some doors and some minds.”

All of this work is taking place while the telescope is tearing through space, more than 1 million km (625,000 mi.) from Earth, about 70% of the way to its L2 destination, which it is set to reach on January 23. Once there, it will take advantage of the delicate gravitational balance of the sun and the Earth and begin orbiting around an invisible point as if it were orbiting a solid body like a planet, always keeping its giant kapron shield facing the sun, ensuring that the mirror remains ultra cold. On-board cryogenic systems will contribute to that natural cooling, bringing some portions of the telescope to temperatures as low as 7 kelvin (-266º C, -447º F)

None of the discoveries Webb could make will come quickly. The telescope’s flight plan calls for it to take a full six months or so after launch before it is fully opened up, booted up and ready to work. For Webb, the landmark moment known as “first light,” when a new telescope opens its eye and begins gazing about at the universe surrounding it, will come in late June or early July.

“We had a big gift on Christmas day,” says Robinson. “Maybe our next big gift will come on the Fourth of July.”

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