What we know about the deployment of the James Webb space telescope

The most powerful telescope to ever launch into space has reached the end of a meticulous assembly process that kept astronomers spellbound for weeks.

Since launching on Christmas morning, the James Webb Space Telescope has made the right choice. It has now crossed the home stretch of its complex deployment phase.

In these final stages, two panels on either side of the telescope’s array of 18 gold-plated hexagonal mirrors, folded over during launch, were put in place to complete Webb’s honeycomb reflector. The 21-foot-wide mirror sends light from the cosmos into a secondary mirror, which then reflects the light back into the telescope’s primary infrared sensor.

Unfolding the mirrors is a crucial step on the way to using the telescope for scientific studies of the Big Bang, exoplanets, black holes, and our solar system. Now that it is complete, NASA considers the telescope “fully deployed”.

The telescope’s deployment phase ended on Saturday morning, after the right side panel of the mirror segment of its three remaining mirrors was secured in place. The left side completed its deployment on Friday, a process that took five and a half hours.

A live NASA video feed showed mission managers monitoring the deployment from the mission control room at the Space Telescope Science Institute in Baltimore, the telescope’s central operations center.

At approximately 8:53 a.m. Eastern Time, mission officials sent out the first commands to begin deploying the mirrors. Shortly before 10:30 a.m., the panel slowly opened so that the three hexagonal mirrors fit together perfectly with the other 15. The staff applauded before moving on to the next steps of locking the mirrors in place. This process ended at 1:17 p.m.

“How does it feel to make history everyone?” You just did it, ”said Thomas Zurbuchen, NASA’s chief scientist, in remarks to the mission at the Space Science Telescope Institute in Baltimore.

Earlier in the live video program, Dr Zurbuchen described himself as emotional when the telescope’s mirrors finally fell into place.

“What an incredible step,” he said. “We see this beautiful pattern in the sky now almost complete. “

But it was not possible to see what was happening on the telescope itself.

Rockets and some spacecraft have built-in cameras so engineers on Earth can monitor their behavior in space. So, one would expect engineers to ship cameras aboard the James Webb Space Telescope, the most expensive and technically complex observatory to ever launch into space, with 344 “single points of failure.”

Think again.

There are no surveillance cameras on the telescope. Instead, engineers depend on switches, sensors, and motors to track its state during deployment.

NASA dropped the idea of ​​including surveillance cameras on Webb due to technical complexities and risks. The new size and shape of the telescope – with one side of its lens hood deflecting enormous amounts of heat and sunlight and the other side heavy with instruments basking in the freezing darkness – would require multiple cameras. tailored. The wires and mounts from these cameras would add weight and risk to an already heavy telescope, the agency said in a blog post.

“It’s not as simple as adding a doorbell camera or even a rocket camera,” said Paul Geithner, NASA deputy project manager for the technical side of the Webb program.

Since Webb’s launch, engineers have completed more than a dozen major steps in the deployment phase to bring the telescope to its final shape, involving hundreds of moving parts such as switches, motors, pulleys and Cables. The process began less than 30 minutes after launch last month, when Webb’s solar panel deployed – the only step filmed as the telescope split into space with its rocket, which had an onboard camera.

The telescope has passed a number of milestones since, doing well in defusing the anxiety of astronomers and allaying fears that a structure as complex as Webb could run into trouble on its million-mile journey to ‘to where it will stay in space. The telescope was powered up, deployed antennas, mechanically unfolded various limbs, and, in the most technically complex milestone, delicately stretched five layers of a tennis court-sized plastic sheet designed for protect the telescope’s ultra-sensitive camera sensors from the heat of the sun.

The Webb Telescope was designed to probe a crucial part of ancient cosmic history, known to astronomers as the Dark Ages.

Cosmologists assume that the first stars appeared when the universe was only around 100 million years old. (Today it is 13.8 billion years old.) The most distant and oldest galaxy seen by astronomers, using the Hubble Space Telescope, dates from when the universe was no longer old, 400 million years after the Big Bang. What happened during those 300 million years that the universe took a luminous flight, how the Big Bang turned into a sky full of constellations and life, is a mystery.

The telescope will also help astronomers better study supermassive black holes at the center of galaxies and planets orbiting other stars in our galaxy.

To carry out these scientific observations, the Webb telescope relies on a primary mirror 6.5 meters in diameter, compared to 2.4 meters for the Hubble mirror. This gives it about seven times the light gathering capacity and therefore the ability to see further into the past.

Another crucial difference is that it is equipped with cameras and other instruments sensitive to infrared radiation, or “heat.” The expansion of the universe causes light that would normally be in visible wavelengths to travel to longer infrared wavelengths normally invisible to human eyes.

Engineers had to invent 10 new technologies along the way to make the telescope more sensitive than the Hubble. Overly optimistic schedule projections, occasional development crashes and disorganized cost reports have dragged the schedule through 2021 and pushed the overall cost to $ 10 billion.

To understand the observational powers of the James Webb Space Telescope and how it will help astronomers with their research, try these two augmented reality experiences in your own space with a smartphone connected to Instagram.

The first will show you where in space and time the Webb will be looking with a 3-D map of the observable universe. It traces some of the spacecraft’s earliest targets, including potentially Earth-like exoplanets and the earliest known galaxies. Try it out here on Instagram.

The second augmented reality experience shows how the Webb will get a visual boost from the power of the gravitational lens.

Place a virtual black hole in your space and observe how it behaves like a magnifying glass on your surroundings. This same technique will help astronomers study the early universe. Try it out here on Instagram.

Noah Pisner contributed reports.

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