NASA’s James Webb Space Telescope reaches its final cosmic destination


Artist’s impression of the James Webb Space Telescope.

NASA GSFC/CIL/Adriana Manrique Gutierrez

Born from the visionary dreams of an ambitious crew of scientists, NASA’s $10 billion James Webb Space Telescope lifted off on December 25, ready to peer deep into the cosmos and capture images of the universe as it was at the beginning of time. Cheers echoed around the world as we witnessed the inauguration of the next great chapter in astronomy.

But Webb still had many miles to go. As he unfurled his origami-like folds while transiting the cold, dark void of space, the explorer made his way to his cosmic work desk at the second Lagrange point, or L2, where the gravity of the sun and the earth balance each other to keep the satellite in a stable place.

Monday, just after 11 a.m. PT/2 p.m. ET, Webb has reached his final destination. NASA engineers powered Webb’s thrusters for nearly five minutes to perfect the probe’s positioning. Beyond applause, the milestone was greeted with a well-deserved exhale.

“Webb, welcome home!” NASA Administrator Bill Nelson said in a statement. “Congratulations to the team for all their hard work ensuring Webb’s safe arrival at L2 today. We’re one step closer to uncovering the mysteries of the universe. And I can’t wait to see the premieres. Webb’s new views on the universe this summer!”

Engineering teams celebrate at the Space Telescope Science Institute in Baltimore as the second main wing of NASA's James Webb Space Telescope mirror unfolds

Engineering teams at the Space Telescope Science Institute in Baltimore celebrate the deployment of the second main mirror wing of NASA’s James Webb Space Telescope, before beginning the process of locking the wing in place January 8.

NASA/Bill Ingalls

Webb’s Galactic Address

At the second Lagrange point, our new lens on the universe is now 1 million kilometers from Earth, well beyond the moon’s orbit, still on the side of our planet that isn’t facing the sun. .

Illustration showing Webb's distance from Earth

Webb will orbit the sun 1.5 million kilometers (1 million miles) from Earth at what is called the second Lagrange point or L2. Note: This graphic is not to scale.


At this point of gravitational equilibrium, Webb can limit his fuel consumption, has an unobstructed view of the cosmos and its sunshade can shield it from the heat of the sun, earth, and moon to maintain the freezing temperatures the telescope needs. The scope must live in a constant cold state as its ability to unlock previously unseen regions of space lies in its infrared imaging processors.

These fascinating machines work by detecting precise heat signals in the cosmos, so the heat from its cosmic neighbors – and even from Webb himself – acts as noise in the data. You can read more about the science behind infrared here.

“If you imagine looking at a telescope at night with your own eyes and someone shines a spotlight in your eyes, you can’t see very well,” said Alison Nordt, director of space science and instrumentation at aerospace giant Lockheed Martin and part of the Webb team.

“So if you have a telescope dedicated to infrared and you have it at room temperature, then it’s flooded with its own light, which is its own heat.”

Now that NASA has locked Webb in place in L2 orbit, it is waiting for the probe to cool down completely, which will take several weeks. Then, as Webb is pulled along its path, the team says it will focus on ensuring that all aspects of the groundbreaking space explorer – such as its 18 mirror segments and infrared imagers – are aligned. and ready for action.

In a few months, we will receive our first unfiltered image of the universe.


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