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Science

Webb Space Telescope’s Mirrors Are Fully Deployed

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The Webb Space Telescope completed its complex mirror deployment this week, and the observatory is getting tantalizingly close to completing its journey to L2, where it will orbit the Sun a million miles away from Earth.

Webb is traveling to the second Lagrange point, a position in space that will allow the telescope to use minimal fuel to stay in position. From L2, the telescope will observe the early universe and exoplanets in the infrared and near-infrared wavelengths. The telescope is expected to overhaul our understanding of the universe’s birth and evolution, as it will peer farther back in time than the Hubble Space Telescope, Webb’s predecessor, which was launched in 1990.

Webb rocketed to space on December 25 from French Guiana and has since traversed 860,000 miles. During this journey, the telescope been steadily unfurling; to make it practical to launch, engineers had to fold it up like a caterpillar in a chrysalis. In careful steps, it has unfurled its sunshield and deployed its mirrors, with the latter step fully completed this week.

Webb has 18 primary mirror segments (the primary mirror is the big honeycomb structure that stands perpendicular to the sunshield) and a secondary mirror; the mirror segments are adjustable and had to be individually shifted from their launch configuration to their positions for scientific observations. NASA Administrator Bill Nelson confirmed the completed mirror deployment on Wednesday.

Tiny incremental adjustments to the mirror positions will happen over the next several months to get everything into the right optical alignments for observation, according to the Webb deployment schedule. But now that deployment is done, only one major step remains: the fuel burn to insert the telescope at L2. This is the final fuel burn by Webb during its deployment schedule, though future burns will happen occasionally to correct the telescope’s orbit.

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The telescope should be orbiting L2 by January 23, after which it will have five months of commissioning to prepare it for scientific observations. The telescope’s million-mile journey is just the preamble to a brilliant scientific career, which could last some 20 years. 

More: New Video Shows Webb Space Telescope’s Goodbye to Earth



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Webb Space Telescope Deploys Secondary Mirror as It Zooms Toward Final Destination

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Animation showing the deployment of the secondary mirror tripod.
Gif: NASA/Gizmodo

The James Webb Space Telescope has successfully deployed the tripod that holds the observatory’s secondary mirror, in what is a critical milestone for the mission.

Webb launched on Christmas Day, but a lot has already happened, including the successful deployments of the observatory’s solar array and five-layer sunshield, the latter of which was completed just yesterday. Today, the Webb team shifted its focus to the secondary mirror, in what is the first in a series of deployments having to do with Webb’s optics.

The secondary mirror, measuring 2.4 feet (0.77 meters) wide, is located on the tips of three long booms and is one of the most important components of the $10 billion observatory.

Webb is a three mirror anastigmat telescope consisting of the large 21.3-foot-wide (6.5-meter) primary mirror, the secondary mirror, and a tertiary mirror. The primary mirror, using its 18 gold-plated segments, will collect incoming light from distant stars, galaxies, and exoplanets, and then reflect a focused beam to the secondary mirror. The beam will then bounce back toward the primary mirror and enter into the tertiary and fine steering mirrors. There, the precious light will finally reach the four scientific instruments situated behind the primary mirror.

A view of the fully deployed secondary mirror during testing.
Photo: NASA/C. Gunn

Today’s deployment of the secondary reflector tripod began at 10:40 a.m. EST. The first step was to release a series of launch locks that prevented the folded-up telescope from getting damaged during launch. Following a quick confidence check, the controllers sent a command for the tripod to make a single small move, which happened at 11:08 a.m. Happy with the result, controllers then issued a command to make the full move—the release of the secondary support structure.

A data-driven, real-time animated view of the telescope shown in NASA’s live webcast of the deployment depicted the tripod slowly shifting into position. The two bottom legs moved into place, while the upper leg, with its one hinge, unfolded as expected. The support structure reached its fully extended position at 11:20 a.m. EST, some 11 minutes after the full move command was issued. Controllers then latched the secondary mirror into place, in a process that lasted for 45 minutes.

Screenshot from NASA’s broadcast of the secondary mirror deployment, showing an animated view of the Webb telescope and the control rooms.
Screenshot: NASA TV

The successful unfolding of the secondary reflector tripod sets the stage for the next step: testing the mirror to make sure it moves on command. Assuming that goes well, the team will then unfold and latch the two primary mirror wings. While all this is happening, the telescope, along with its scientific instruments, will undergo rapid cooling now that the sunshield is in place. NASA says it should take several weeks for Webb to reach stable temperatures.

The observatory is currently en route to its destination, Lagrange point 2, which is located approximately 1 million miles (1.5 million kilometers) from Earth. Science operations should begin in around six months, at which time the infrared telescope will gather light from the first galaxies and stars to appear in the universe.

More: Here’s What Could Still Go Wrong With the Webb Space Telescope.

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Science

With James Webb Space Telescope’s huge sunshield in place, focus shifts to big mirrors

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The James Webb Space Telescope is moving briskly on to its next big deployment.

On Tuesday (Jan. 4), Webb finished bringing its huge, five-layer sunshield up to the proper tension, wrapping up the most complex and tricky operation of the $10 billion observatory’s lengthy deployment phase. 

The mission team can therefore now turn to the next big-ticket item on its to-do list: getting the telescope’s secondary and primary mirrors into the proper configuration. And the ball on that will get rolling very soon.

“We just finished deploying our sunshield today, but wait, there’s more! #NASAWebb’s secondary mirror is planned to be unfolded tomorrow, Jan. 5th, in the morning (Eastern time),” NASA officials said Tuesday evening via the mission’s Twitter account.

Related: Building the James Webb Space Telescope (gallery)

That target timeline apparently changed as Tuesday wore on. During a news conference early Tuesday afternoon, for example, mission team members said mirror deployment likely wouldn’t begin in earnest for a few more days.

“So I would say probably by this weekend we will start that process,” Alphonso Stewart, James Webb Space Telescope deployment systems lead at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said during the news conference. “But then it runs for about 10 days. That whole mirror deployment is a 10-day period.”

Webb’s 21.3-foot-wide (6.5 meters) primary mirror consists of 18 hexagonal segments arrayed across a central platform and two smaller side “wings.” These wings were folded back prior to launch so the assembly could fit inside the protective payload fairing of Webb’s Ariane 5 rocket. (The sunshield is about the size of a tennis court, so it too had to unfurl after liftoff.) Deployment of the primary mirror involves extending the two wings and locking them in place.

Webb’s secondary mirror is so named because it’s the second surface, after the primary, that light will hit on its way into the telescope’s four science instruments. The 2.4-foot-wide (0.74 m) secondary mirror sits at the end of several booms, which must be extended.

The secondary mirror will be deployed first. That operation is preceded by heating up the motors that deploy the mirror structure — an activity that Stewart had said would begin on Tuesday night.

“Following that, the next two days, we’ll start heating [motors] in preparation for the wing mirror deployments,” he said during Tuesday’s news conference.

Timeline shifts with Webb are not terribly surprising or concerning; team members have stressed repeatedly since the observatory’s Dec. 25 launch that most deployment operations are flexible.

Webb is designed to pick up faint heat signals from the early universe, challenging work that requires its optics and instruments to remain extremely cold. That’s why the observatory has such a big sunshield and why it will operate at the Earth-sun Lagrange Point 2 (L2), a gravitationally stable spot about 930,000 miles (1.5 million kilometers) from our planet. At L2, Webb will stay aligned with Earth, the sun and the moon, allowing the sunshield to block light and heat from these bodies continuously.

If all goes according to plan, the telescope will slip into orbit around L2 with an engine burn 29 days after launch (on Jan. 23). At that point, Webb will be at its final destination with all major deployments complete. But the observatory won’t be ready to begin its science work yet.

The mission team will still need to align the 18 primary mirror segments precisely so they act as a single light-collecting surface and check out and calibrate Webb’s instruments. These jobs will take several months to complete. Science operations are expected to begin this summer and last at least five years.

Editor’s note: This story was updated at 6:50 p.m. EDT on Tuesday (Jan. 4) with the new deployment timeline. The original version stated that secondary mirror deployment would likely begin this weekend, a target that mission team members laid out during Tuesday’s press conference. 

Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook. 



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Webb telescope successfully unfurls its tennis court-size sunshield in space

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The James Webb Space Telescope, which launched on Christmas Day, successfully completed the deployment of its 70-foot (21-meter) sunshield on Tuesday. This critical milestone is one of several that must occur for the NASA observatory to function properly in space, and having achieved it was a big relief for the Webb team.

“Unfolding Webb’s sunshield in space is an incredible milestone, crucial to the success of the mission,” said Gregory L. Robinson, Webb’s program director at NASA Headquarters, in a statement. “Thousands of parts had to work with precision for this marvel of engineering to fully unfurl. The team has accomplished an audacious feat with the complexity of this deployment — one of the boldest undertakings yet for Webb.”

It’s one of the most challenging spacecraft deployments NASA has ever attempted, according to the agency.

The massive five-layer sunshield will protect Webb’s giant mirror and instruments from the sun’s heat. Both the mirror and instruments need to be kept at a very frigid negative 370 degrees Fahrenheit (negative 188 degrees Celsius) to be able to observe the universe as designed. Each of the five sheets is as thin as a human hair and is coated with reflective metal.

When Webb launched, the sunshield was folded up to fit inside the Ariane 5 rocket that carried the telescope into space. The eight-day process to unfold and tighten the protective shield began on December 28. This included unfolding the support structure for the shield over the course of multiple days before the tensioning, or tightening, of each layer could begin.

The fifth layer of the sunshield was tightened and secured into place Tuesday at 11:59 a.m. ET.

Overall, the entire process, which was controlled by teams on Earth, included the perfect, coordinated movement of hundreds of release mechanisms, hinges, deployment motors, pulleys and cables.

“The membrane tensioning phase of sunshield deployment is especially challenging because there are complex interactions between the structures, the tensioning mechanisms, the cables and the membranes,” said James Cooper, NASA’s Webb sunshield manager, based at Goddard Space Flight Center, in a statement. “This was the hardest part to test on the ground, so it feels awesome to have everything go so well today.”

The teams have been working 12-hour shifts to ensure that everything goes smoothly with Webb’s deployments.

With the sunshield successfully in place, Webb’s project manager Bill Ochs said the telescope has overcome the potential for 70% to 75% of the more than 300 single-point failures that could disrupt its ability to function.

“This milestone represents the pioneering spirit of thousands of engineers, scientists, and technicians who spent significant portions of their careers developing, designing, manufacturing, and testing this first-of-its kind space technology,” said Jim Flynn, sunshield manager at Northrop Grumman, NASA’s primary contractor for Webb, in a statement.

The telescope has the ability to look back in time, using its infrared observations to reveal otherwise invisible aspects and look deeper into the universe than ever before.

The Webb telescope will look at every phase of cosmic history, including the first glows after the Big Bang that created our universe and the formation of the galaxies, stars and planets that fill it today. Its capabilities will enable the observatory to peer inside the atmospheres of exoplanets and investigate faint signals from the first galaxies formed 13.5 billion years ago.

“This is the first time anyone has ever attempted to put a telescope this large into space,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate, in a statement. “Webb required not only careful assembly but also careful deployments. The success of its most challenging deployment — the sunshield — is an incredible testament to the human ingenuity and engineering skill that will enable Webb to accomplish its science goals.”

What comes next

Webb is expected to take about 29 days to reach its intended orbit a million miles from Earth, with other critical steps along the way — and that includes another big challenge later this week: unfolding the telescope’s mirror.

The mirror can extend 21 feet and 4 inches (6.5 meters) — a massive length that will allow it to collect more light from objects once the telescope is in space. The more light the mirror can collect, the more details the telescope can observe.

It’s the largest mirror NASA has ever built, but its size created a unique problem. The mirror was so large that it couldn’t fit inside a rocket. Engineers designed the telescope as a series of moving parts that can fold origami-style and fit inside a 16-foot (5-meter) space for launch.

This is the next series of crucial steps for Webb — making sure the mirror’s 18 hexagonal gold-coated segments unfold and lock together. All of these steps are expected to be completed by the end of this week.

Finally, Webb will make one more trajectory adjustment to insert itself into an orbit that reaches beyond the moon.

While that rounds out the 29 days, the telescope will go through a period of commissioning in space that lasts for about five and a half months, which involves cooling down, aligning and calibrating its instruments. All of the instruments also will go through a checkout process to see how they are functioning.

Webb will begin to collect data and its first images later in 2022, and those are expected to be released in June or July, forever changing the way we see and understand the universe.

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James Webb Space Telescope completes tricky sunshield deployment

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The James Webb Space Telescope has successfully deployed all five layers of its tennis-court-sized sunshield, a prerequisite for the telescope’s science operations and the most nerve-wracking part of its risky deployment.

The challenging procedure, which required careful tensioning of each of the five hair-thin layers of the elaborate sunshield structure was a seamless success today (Jan. 4). Its completion brought huge relief to the thousands of engineers involved in the project over its three decades of development, as well as the countless scientists all over the world who eagerly await Webb’s groundbreaking observations. 

“Yesterday, we did not think we were going to get through the first three layers,” Keith Parrish, the observatory manager for the James Webb Space Telescope, said in a live NASA webcast during today’s deployment. “But the team just executed everything flawlessly. We were only planning to do one yesterday, but that went so well. They said hey, can we just keep going? And we almost had to hold them back a little bit.” 

Related: A James Webb Space Telescope astronomer explains how to send a giant telescope to space — and why

Securing the right tension for each of the sunshield’s five layers was achieved today using a complex system of cables and motors pulling at the corners of the diamond-shaped sunshield. 

The elaborate tightening of the sunshield’s diamond-shaped layers began on Monday (Jan. 3). NASA originally expected each layer to take one day, but by the end of the first day, three layers were successfully tensioned with the final two tightened on Tuesday (Jan. 4). 

The successful deployment of the fourth layer was confirmed at 10:23 a.m. EST (1523 GMT) as the telescope cruised some 546,000 miles (879,000 kilometers) from Earth. The final, fifth layer, was tensioned at 12:09 p.m. EST (1709 GMT) and was met with cheers and applause from control teams. 

“This is a really big moment, I just want to congratulate the entire team,” one of the operations managers could be heard saying in the webstream upon confirmation of the fifth layer being completed. “We still have got a lot of work to do, but getting the sunshield deployed is really, really big.”

This sunshield deployment was thoroughly tested on Earth but even the most high-tech test lab can’t fully simulate the effects of weightlessness and other factors present in outer space. If anything went wrong, the entire mission, which cost $10 billion and took roughly three decades to build, could have been in jeopardy. 

The James Webb Space Telescope is designed to study the universe in the infrared wavelengths and therefore has to be extremely cold for its sensitive detectors to work as designed.

Since Webb observes infrared light, or heat, it has to be kept at extremely cold temperatures so that there is no heat from Webb that could obscure its observations. By reflecting both incoming solar radiation and heat from planet Earth, the sunshield keeps Webb perfectly cold. 

With the ultimate goal to detect the extremely faint light coming from the most distant stars and galaxies, those that lit up the dark universe in the first hundreds of millions of years after the Big Bang, Webb’s detectors need to be extremely sensitive. Any heat from the telescope would dazzle those detectors and outshine that faint precious signal. 

“We get about a 100 degree Fahrenheit (55 degrees Celsius) drop per layer,” Parrish said. “We get about 600 degrees F (330 degrees C) between the hot side and what I call our coldest temperature on the observatory, the instrument detectors,” which are running at around minus 400 degrees F (minus 235 degrees C), he added.

Against all obstacles

The challenging operation was conducted as humans on Earth contend with a new surge of the COVID-19 virus brought about by the recently discovered Omicron variant, which forced many team members into isolation. 

“One of the things that has been a challenge is people who worked a long time on this, and we had to isolate them,” Parrish said. “Fortunately, in this day and age, we can get them hooked up to our operations loop and they can help us remotely from wherever they are.”

The James Webb Space Telescope is heading for what is known as the Earth-sun Lagrange Point 2 (L2) some 930,000 miles (1.5 million km) away from the planet. L2 is one of five points between the sun and Earth where the interplay of the gravitational forces of the two bodies keeps an object in a stable position with respect to the two bodies. The James Webb Space Telescope will thus orbit the sun, permanently aligned with Earth, hiding from the star’s scorching rays. 

With the sunshield now fully unfurled and tensed, the operations teams will move on to the deployment of the telescope’s secondary mirror. 

“Starting this evening, we’re going to get some heaters on to start heating up the motors that actually do the deployment of our secondary mirror system,” said Parrish. “We’ll get that heated up and we’ll get on with that.”

Webb will reach L2 by the end of January. Once the scope arrives, it will be fully deployed, including its 21 feet 4 inches-wide (6.5 meters) primary mirror, which too had to be folded for launch because of its large size. 

The mirror’s 18 gold-coated hexagonal segments will take 100 days to cool down to their operational temperature. Only after that will they be carefully aligned so that the seams between them are completely smooth, allowing astronomers to take sharp images of the most distant universe. First images from the telescope, the most complex and expensive space observatory ever built, are expected in the summer of 2022. 

Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook. 



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Webb Space Telescope Deploys Its All-Important Sunshield

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Artist’s conception of the Webb telescope.
Image: NASA

NASA, after a slight technical delay, has now tightened all five layers of the Webb Telescope’s protective sunshield.

The tensioning of the first three layers began early Monday, in a process that lasted for nearly six hours. The remaining two layers—the ones farthest from the Sun—were tightened today, NASA announced in a tweet. This is welcome news, as the successful deployment of the sunshield sets the stage for the next phase of the mission: deploying the telescope’s gigantic mirror.

Measuring 47 feet (14.3 meters) across and 70 feet (21.3 meters) long, the kite-shaped sunshield will protect Webb from stellar radiation and minimize interference caused by the observatory’s instrumentation. Webb needs this shield to function properly, making this a critically important phase of the mission—but getting all five membranes to stretch out tight is more difficult than it sounds.

James Cooper, NASA’s Webb sunshield manager, said “complex interactions between the structures, the tensioning mechanisms, the cables and the membranes,” is what makes this phase so challenging, as he explained in a NASA blog post. “This was the hardest part to test on the ground,” he added, saying the Northrop Grumman and NASA team is “doing great work.”

At a briefing with reporters on Monday, Bill Ochs, Webb project manager at NASA’s Goddard Space Flight Center, said around three-quarters of the observatory’s 344 potential points of failure will be retired once the sunshield is fully tensioned.

Last week, the deployment of two booms on either side of the observatory took longer than expected, so controllers were given a day off on January 1 to rest. Tightening of the sunshield was then scheduled for January 2, but NASA instead used the day to resolve a pair of minor issues. Specifically, the team had to rebalance Webb’s solar array to draw more power and re-orient the spacecraft to reduce the amount of sunlight hitting the motors used for tensioning, according to NASA.

The delay also provided an opportunity for the team to study how Webb is behaving in its new space environment. “Nothing we can learn from simulations on the ground is as good as analyzing the observatory when it’s up and running,” Ochs explained in a post on January 2. “Now is the time to take the opportunity to learn everything we can about its baseline operations.”

The brief pause is not a problem, as the team is not currently under any kind of time pressure; NASA says “flexibility [is] built into the timeline.” The next step now is to deploy the tripod holding the secondary mirror.

Those minor glitches aside, everything seems to be going exceptionally well, knock on wood. As an added bonus, the precision of the Webb launch means this historic mission could last for more than 10 years, owing to the fuel savings. The observatory is expected to enter into the science phase of its mission in approximately six months, at which time it will gaze upon the oldest galaxies in the universe, look for new exoplanets, and scan distant atmospheres in search of extraterrestrial life.

More: Here’s what could still go wrong with the Webb space telescope.



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NASA presses ahead with Webb space telescope sunshield deployment

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Engineers activating the James Webb Space Telescope fine-tuned its electrical power system to better cope with the actual space environment and cooled down slightly warmer-than-expected motors before pressing ahead Monday with final deployment of the observatory’s critical sunshade.

Bill Ochs, the NASA project manager, said tightening up the sunshade’s five hair-thin layers, carefully pulling them taut with motor-driven cables running through multiple pulleys, likely would take three days to complete. But by Monday night, three of the five layers had been pulled into shape, with the final two awaiting tightening Tuesday.

The sunshade deployment has long been considered one of Webb’s most challenging hurdles, but “I don’t expect any drama,” Ochs said.

The James Webb Space Telescope’s five-layer sunshade, seen during testing at Northrop Grumman’s Redondo Beach, California, processing facility.

NASA


“I always tell folks, the best thing for operations is boring,” he said. “And that’s what we anticipate over the next three days. I think we’ll all breathe a sigh of relief once we get to the final layer five tensioning. But I don’t expect drama.”

Webb, the most expensive science probe ever built, was launched with great fanfare atop a European Space Agency-provided Ariane 5 rocket on Christmas Day, bound for an orbit around the sun a million miles from Earth.

Designed to capture infrared light from the first stars and galaxies to form in the wake of the Big Bang, Webb is extraordinarily complex. But other than minor growing pains common to all new spacecraft, Ochs said the $10 billion observatory is moving through its initial activation almost exactly as planned.

“We are still in the getting-to-know-you phase with the telescope,” he told reporters in a morning teleconference. “All satellites will always be a little bit different on orbit than they are on the ground, and it takes time to get to know that, understand their characteristics.

“That’s a lot of what we’ve been doing over the last week, as well as still making excellent progress on the commissioning timeline.”

The telescope’s solar array was deployed as planned moments after reaching space, two trajectory correction thruster firings were carried out, a high-gain antenna was unlimbered and pointed at Earth and two pallets holding the sunshade membranes were rotated into position.

An extendable tower lifted Webb’s primary mirror and instruments about four feet above the still-folded sunshade, providing clearance and additional isolation from the heat generated by the spacecraft’s electronics. A “momentum flap” then was deployed to counteract slight forces imparted by the solar wind.

After protective covers were rolled back out of the way, two telescoping booms extended from the sunshade pallets on New Year’s Eve, pulling out the Kapton membranes into their now-iconic kite-like shape.

“The tensioning of the layers is obviously the next big step that we go through,” Ochs said. “When we complete tensioning of all five layers, we will have retired somewhere between 70 and 75 percent of those 344 single-point failures that were discussed prior to the mission.”

He was referring to the number of non-redundant devices and mechanisms required for Webb’s myriad deployments that have no backups if something goes wrong. All of them simply have to work.

An artist’s impression of the Webb telescope with its sunshade and optical system fully deployed.

NASA


The sunshade is required to block out the heat of the sun, cooling Webb’s 21.3-foot-wide primary mirror and instruments to nearly 400 degrees below zero, cold enough to register faint infrared light from the first stars and galaxies to light up after the Big Bang.

To achieve the required ultra-low temperatures, each layer must be pulled taut by motor-driven cables running through multiple pulleys, a process that also lifts and separates the membranes to allow gaps for heat to dissipate.

That final tensioning was held up over the weekend to give engineers time off after a busy first week of deployment activity and then to assess the performance of Webb’s five-panel solar array and its battery system.

As it turned out, factory presets governing the solar array’s output needed adjustment to take into account the actual temperatures Webb is experiencing in space. At the same time, the telescope was re-oriented slightly to cool six motors needed to pull the sunshade layers taut.

“Everything is hunky-dory and doing well now,” said Amy Lo, Webb systems engineer with prime contractor Northrop Grumman. “The observatory was never in danger, we were never power starved. … The rebalancing of the array gives us quite a lot of margin (for) the expected increase in power that we will be needing as we proceed on.”

As for the motors, Lo said they were never out of limits, just a bit warmer than optimum. Playing it safe, Webb was reoriented Sunday to improve cooling and “we’ve got a lot of margin now on our temperature.”

William Harwood

Bill Harwood has been covering the U.S. space program full-time since 1984, first as Cape Canaveral bureau chief for United Press International and now as a consultant for CBS News. He covered 129 space shuttle missions, every interplanetary flight since Voyager 2’s flyby of Neptune and scores of commercial and military launches. Based at the Kennedy Space Center in Florida, Harwood is a devoted amateur astronomer and co-author of “Comm Check: The Final Flight of Shuttle Columbia.”

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NASA delays tightening James Webb Space Telescope sunshield to study power system

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NASA personnel are spending the day studying the power subsystem of the massive James Webb Space Telescope to ensure the observatory is ready to execute a key procedure: tensioning its vast sunshield.

The Webb space telescope, which launched on Dec. 25, is conducting a month-long deployment procedure necessary to prepare the telescope to gather data. But most steps in that procedure are controlled from the ground: While NASA has a tentative schedule for the work, mission leaders can decide to adjust the timeline along the way. So after taking Saturday (Jan. 1) as a rest day, the Webb team is spending Sunday (Jan. 2) studying the observatory’s power subsystem, NASA announced.

“Nothing we can learn from simulations on the ground is as good as analyzing the observatory when it’s up and running,” Bill Ochs, Webb project manager at NASA’s Goddard Space Flight Center (GSFC) in Maryland, said in an agency statement released Sunday (Jan. 2). “Now is the time to take the opportunity to learn everything we can about its baseline operations. Then we will take the next steps.”

Live updates: NASA’s James Webb Space Telescope mission
Related: How the James Webb Space Telescope works in pictures

In particular, the team is focused on the temperature of a set of motors that will be used during sunshield tensioning, the process that separates and smooths the five delicate layers of the kite-shaped sun deflector. (Webb specializes in infrared observations, which are sensitive to heat, making the sunshield a vital component of the observatory.)

“We’ve spent 20 years on the ground with Webb, designing, developing, and testing,”  Mike Menzel, Webb’s lead systems engineer at GSFC said in the same statement. “We’ve had a week to see how the observatory actually behaves in space. It’s not uncommon to learn certain characteristics of your spacecraft once you’re in flight. That’s what we’re doing right now. So far, the major deployments we’ve executed have gone about as smoothly as we could have hoped for. But we want to take our time and understand everything we can about the observatory before moving forward.”

Tensioning the sunshield is a complex process that NASA expects to take two days. NASA initially intended to start the work on Saturday, but Friday’s operations ran later than expected and the team decided to take New Year’s Day to rest.

And when mission managers decided to take a closer look at the motor temperatures, they didn’t want the team to be working on two aspects of the observatory at once.

After the sunshield is fully tensioned, the team will move on to deploying the secondary mirror.

Although deployment has paused, the observatory is still making progress. As of just before 3 p.m. EST (2000 GMT), Webb was more than 510,000 miles (825,000 kilometers) away from Earth, or 57% of the way to its final destination of the Earth-sun Lagrange point 2. That point, also known as L2, is located nearly 1 million miles (1.6 million kilometers) from Earth in the direction opposite the sun.

Email Meghan Bartels at mbartels@space.com or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook. 



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How to Watch James Webb Deploy Its Sunshield Tomorrow

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The James Webb Space Telescope is continuing the complex process of unfolding its origami-like structure into its final deployed form while traveling through space on its way to its ultimate orbit around the sun. A major part of this process, in which the telescope tensions its sunshield, will be happening tomorrow and NASA will broadcast live coverage of the event. We’ve got the details on what to expect from this and how to watch along at home.

What to expect from the sunshield deployment

James Webb Space Telescope’s sunshield is seen during testing. Chris Gunn – NASA Goddard Space Flight Center

The process of getting the telescope from its launch configuration, folded up inside a rocket, to its full deployment, ready to start science operations, is a complex one. One of the most crucial and delicate parts of this operation is the deployment of the five-layered, tennis court-sized sunshield which will protect the telescope from the heat of the sun.

Over the past week, parts of the sunshield support structure have been deployed into place, culminating in the extension of the two mid-booms which stretched the sunshield across its full 47-foot width.

Now, the sunshield needs to be tensioned. Each of the five layers will be separated and stretched into its final shape, held taut with a space between each layer to allow heat to escape. This begins with the largest layer, which is the one closest to the sun, and works by using a total of 90 cables that are attached to various pulleys to pull the shield into place.

The full deployment is expected to take at least two days.

How to watch the sunshield deployment

Coverage of the sunshield deployment will begin on Sunday, January 2 at 2 p.m. ET (11 a.m. PT). NASA TV will show live broadcast coverage of the tensioning process, and once this is complete there will be a briefing with more information about James Webb and the deployment process.

To watch the broadcast, you can either head to NASA’s website or use the video player embedded near the top of this page.

In addition to coverage of the sunshield deployment, there will also be more coverage of further deployment processes next week. On Tuesday, January 4 there will be live coverage of the deployment of James Webb’s secondary mirror support structure, and on Friday, January 7 there will be live coverage of the unfolding on second of the primary mirror wings. The exact time for these broadcasts has not yet been confirmed, but you can keep an eye on the James Webb Space Telescope blog for more information as it becomes available.

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NASA takes break in JWST deployment after extending sunshield

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WASHINGTON — NASA is taking a one-day break in the deployment of the James Webb Space Telescope after successfully extending booms for the spacecraft’s sunshield.

NASA said Jan. 1 it would wait a day before beginning the process of tensioning the five-layer sunshield, getting it into its final form and ensuring the layers are separated from each other. That effort, now scheduled to begin Jan. 2, will take at least two days to complete.

Spacecraft managers added the pause in the sunshield deployment after working late into the night Dec. 31 to extend two “mid-boom” structures on either side of the spacecraft. Those booms extended the sunshield to its full size. That process started late when sensors indicated that a sunshield cover had not fully rolled up. Controllers decided to go ahead with the deployment of the booms because other data, including from temperature sensors and gyroscopes, were consistent with the removal of the cover.

“The team did what we had rehearsed for this kind of situation: stop, assess and move forward methodically with a plan,” said Keith Parrish, JWST observatory manager at the Goddard Space Flight Center, in a Dec. 31 statement. “We still have a long way to go with this whole deployment process.”

That sensor glitch has been the only issue in the series of deployments by the spacecraft since its launch Dec. 25. NASA noted in a statement that the sunshield deployment relied on 107 membrane release devices, every one of which had to work for the sunshield to extend correctly. All 107 successfully released, the agency stated.

The one-day break in completing the sunshield tensioning will likely push back other activities, NASA said. The tensioning is the final step in completing sunshield deployment, after which controllers will turn their attention to setting up the telescope mirrors. A one-day slip, though, will have little long-term impact on the mission, which will spend six months completing commissioning of the telescope and its instruments.

“Today is an example of why we continue to say that we don’t think our deployment schedule might change, but that we expect it to change,” Parrish said in the Dec. 31 statement about the boom deployment.

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