The most powerful telescope ever launched into space is nearing the end of a painstaking assembly process that has kept astronomers on their toes for weeks.
Since its launch on Christmas morning, the James Webb Space Telescope has made all the right moves. Now it is entering the final stretch of its complex implementation phase.
In these final steps, two panels on either side of the telescope’s array of 18 gold-plated hexagonal mirrors, which folded back during launch, must snap into place to complete Webb’s honeycomb-like reflector. The 5-meter-wide mirror directs light from the cosmos to a secondary mirror, which then reflects the light into the telescope’s main infrared sensor.
The unfolding of the mirrors is a crucial milestone towards using the telescope for scientific studies of the Big Bang, exoplanets, black holes and our solar system. Once completed, NASA will consider the telescope “fully deployed.”
When will the Webb telescope finish unfolding and how can I watch it?
The telescope’s deployment phase is expected to end Saturday morning, after the right panel of the mirror segment of the three remaining mirrors is secured in place. The left side completed its bet on Friday, a process that took five and a half hours.
On Saturday, engineers will instruct the telescope to release a set of latches that held the panel in place during launch. Then, for about five minutes, the panel will swing open slowly so that the three hexagonal mirrors closely match the other 15.
During the operation, NASA will host a live stream on NASA TV and YouTube starting Saturday at 9 a.m. Eastern Time. It will show mission managers monitoring the deployment from the flight control room of the Space Telescope Science Institute in Baltimore, the telescope’s central operations center. The deployment is expected to end a few hours later, around 1:30 p.m.
But you can’t see what’s happening on the telescope itself.
Why are there no cameras on the telescope?
Rockets and some spacecraft have built-in cameras so engineers on Earth can monitor their behavior in space. So you would expect engineers to pack cameras aboard the James Webb Space Telescope, the most expensive and technically complex observatory ever launched into space, with 344 “single points of failure”.
There are no surveillance cameras on the telescope. Instead, engineers rely on switches, sensors, and motors to track status during implementation.
NASA dropped the idea of including surveillance cameras on Webb due to technical complexity and risks. The telescope’s new size and shape — with one side of the hood rejecting massive amounts of heat and sunlight and the other side of the instrument basking in frigid darkness — would require multiple custom-built cameras. Wires and mounts for those cameras would add weight and risk to an already heavy telescope, the agency explained in a blog post.
“It’s not as simple as adding a doorbell camera or even a rocket camera,” said Paul Geithner, NASA’s deputy project manager for the engineering side of the Webb program.
What has happened to the telescope so far?
Since Webb’s launch, engineers have completed more than a dozen major steps in the implementation phase to bring the telescope into its final form, 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 was deployed — the only step captured on video when the telescope broke up in space with its rocket, which had an onboard camera.
The telescope has since passed a number of milestones and does well to allay astronomers’ fears and quell fears that a construct as complex as Webb’s journey from a million miles to the place in space where he will remain, would run into snags. The telescope turned on, deployed antennas, mechanically unfolded several limbs and, in the most technically complex milestone, delicately stretched five layers of a tennis court-sized plastic sheet designed to protect the telescope’s ultra-sensitive camera sensors from the heat of the field. the sun.
Why is the telescope so important to scientists?
The Webb telescope was designed to investigate a pivotal piece of early cosmic history, known to astronomers as the Dark Ages.
Cosmologists suspect that the first stars appeared when the universe was only about 100 million years old. (Today, it is 13.8 billion years old.) The farthest and earliest galaxy seen by astronomers, using the Hubble Space Telescope, dates back to when the universe was older, 400 million years after the Big Bang. What happened during those intervening 300 million years when the universe took flight, how the Big Bang turned into a sky full of constellations and life, is a mystery.
The telescope will also help astronomers to better study supermassive black holes at the center of galaxies and planets orbiting other stars in our galaxy.
To achieve these scientific observations, the Webb telescope relies on a primary mirror with a diameter of 6.5 meters, compared to the mirror on the Hubble, which is 2.4 meters. That gives it about seven times the light-gathering power and thus the ability to see further into the past.
Another crucial difference is that it is equipped with cameras and other instruments that are sensitive to infrared radiation or ‘heat’. The expansion of the universe causes light that would normally be in visible wavelengths to shift to longer infrared wavelengths that are normally invisible to human eyes.
Engineers along the way had to invent 10 new technologies to make the telescope more sensitive than the Hubble. Over-optimistic planning forecasts, incidental development accidents and disorganized cost reporting dragged the timeline into 2021, pushing total costs to $10 billion.