Astronomers are starting to breathe again.
Two weeks ago, the most powerful space observatory ever built soared into the sky, carrying the hopes and dreams of a generation of astronomers with it in a package of mirrors, wires, motors, wires. Cables, pins and thin plastic sheets are tightly wound on a pole. smoke and fire.
On Saturday, the observatory, the James Webb Space Telescope, completed a crucial, final step at around 10:30 a.m. by opening the last section of its golden hexagonal mirrors. Nearly three hours later, engineers sent orders to bolt those mirrors into place, a step that led to it being fully deployed, according to NASA.
This is the latest in a series of sophisticated maneuvers with what the space agency calls 344 “single point of failure” while accelerating away into space. Now the telescope is almost ready for business, although more stressful times remain in its future.
“I’m very emotional about that,” said Thomas Zurbuchen, chief science officer at NASA, of all the telescope’s mirrors finally snapping into place. “What an incredible milestone – we see the beautiful model out there in the sky now almost complete.”
The James Webb Space Telescope, named after a former NASA administrator who oversaw the formative years of the Apollo program, has 25 years and $10 billion in the making. It is three times the size of the Hubble Space Telescope and is designed to look further into the past than its famous predecessor to study the first stars and galaxies to light up in normal time. bright.
The Ariane rocket launch on the morning of December 25 was perfect; so perfect that engineers say it saves enough maneuvering fuel to extend the mission’s estimated 10-year life, perhaps another 10 years, said Mike Menzel, mission systems engineer at NASA Goddard, said. But the telescope must complete a month-long journey to a point a million miles above the moon’s orbit, called L2, where the gravitational fields of the Earth and the Sun intersect. to create the conditions for a stable orbit around the sun.
With a main mirror measuring 21 feet across, Webb was too big to fit a rocket, and so the mirror made of segments, 18 gilded hexagons folded together, would have to pop in. position when the telescope is in space.
Another challenge is that the telescope’s instruments must be sensitive to infrared or “thermal radiation,” a form of electromagnetic radiation invisible to the human eye. Due to the expansion of the universe, the earliest and most distant galaxies are flying away from us so quickly that visible light from those galaxies is shifting to longer infrared wavelengths. As a result, Webb will see the universe in colors the human eye has never seen.
But to detect infrared radiation from distant sources, the telescope must be very cold, just a few degrees above absolute zero, so that the telescope does not interfere with the work.
After years of experimental deployments on Earth, little surprises in space came during Webb’s rollout, or “telescope familiarization phase,” said Bill Ochs, an engineer at the Flight Center Goddard Space Flight and a project manager of the telescope, told reporters on Monday.
Mission managers detected high temperatures on an onboard engine used only during deployment, so engineers appointed the telescope on Sunday to protect the instrument from the heat. of the sun. Webb’s solar arrays were then retuned when engineers noticed that the telescope had a smaller-than-expected power reserve.
One of the most horrifying moments came on Tuesday, with the successful opening of a giant sun visor the size of a tennis court. It is designed to keep the telescope in the dark and cool enough that its own heat doesn’t obscure heat detected from distant stars. The screen is made of five layers of plastic called Kapton, which is similar to Mylar and is more fragile, and sometimes tears during deployment maneuvers.
In fact, this time it went perfectly.
“It went extremely smoothly. I feel like we’re all shocked that there’s no drama at all,” said Hillary Stock, sunshield implementation specialist at Northrop Grumman, the telescope’s main contractor.
Then, on Wednesday, the telescope opened its secondary mirror, which points at 18 hexagons, reflecting what the telescope sees back to its sensors.
“We’re about 600,000 miles from Earth, and we actually have a telescope,” said Ochs in the mission operations control room at the Space Telescope Science Institute in Baltimore.
As this telescope worked from one job to another, the astronomers who had been waiting for this telescope for 25 years began to relax.
“Strangely I don’t feel anxious anymore, my inherent optimism (hello, optimism bias & anchor bias) is ready,” said Priyamvada Natarajan, a cosmologist from Yale, wrote in an email.
Three days later, the mirrors were finally locked up, and the mission control team burst into applause and a flurry of high punches and jabs.
“How do people feel about making history?” Dr. Zurbuchen questioned the mission’s managers in Baltimore after closing. “You just did it.”
“NASA is a place where the impossible becomes possible,” said Bill Nelson, a former senator and astronaut who is now a NASA administrator.
Garth Illingworth of the University of California, Santa Cruz, said: “I cannot describe how wonderful it feels to have a full mirror. It is an amazing achievement for the JWST Team. ”
Alan Dressler of the Carnegie Observatory, who chaired a report leading to what would become the Webb telescope, said “what resonates at the moment is the extraordinary ability of our species to collaborate, our organize thousands of people to work carefully, without rest, without selfishness. , and seemingly relentlessly moving toward some human better. “
Chanda Prescod Weinstein, an astrophysicist at the University of New Hampshire, echoed her remarks: “This is a reminder of how successful people can be when they work together.”
Although the telescope is considered fully deployed, much work remains to be done. According to Menzel, there are still 49 of those “single points of failure”. Problems with any of them could affect the mission’s individual instruments or the spacecraft as a whole.
At the end of January, the telescope will be in its final orbit at L2. Astronomers will spend the next five months adjusting the mirrors to bring them into focus and begin testing and calibrating their instruments.
Then the real science will begin. Astronomers say the first image from the Webb telescope will appear in June, but no one has said it yet.
Jane Rigby, a project scientist for the mission at NASA Goddard, said in a press conference Saturday that the first images created during mirror alignment will be blurry and ugly. But once the mirrors are coordinated, she says the telescope’s image will “knock everyone off”.
Dr Rigby said: “We are planning a series of ‘fantastic’ images to be released at the end of the run as we begin normal science operations.
“I can’t wait for the first light and then the first science,” Michael Turner, a veteran cosmologist at the Kavli Foundation in Los Angeles, wrote in an email. “It will be even better for our COVID-stricken souls than Ted Lasso.”
https://www.nytimes.com/2022/01/08/science/james-webb-telescope-nasa-deployment.html James Webb Telescope Completes Space Deployment