The most powerful telescope is sent into space this 2021 1:13
The James Webb Space Telescope has reached its final destination, nearly a month after launch.
Since lifting off from French Guiana on Dec. 25, the telescope has unfurled its tennis-court-sized sunshield and huge golden mirror that will help it study the universe in new ways and peer inside the atmosphere of exoplanets.
The most powerful telescope ever built is about to change the way we see the universe
The telescope's point of view is almost a million and a half kilometers from Earth and beyond the Moon itself.
The space observatory underwent its last power-up on Monday to enter this orbit called L2.
"Webb, welcome home!" NASA Administrator Bill Nelson said in a statement.
"Congratulations to the team for all their hard work to ensure Webb's safe arrival at L2 today. We are one step closer to unlocking the mysteries of the universe. And I can't wait to see the first new images from the Webb universe this summer."
Although it seems unusual that the telescope takes almost a month to reach orbit, Webb is unique.
"Think of throwing a ball straight into the air, as hard as you can; it starts off really fast, but slows down as gravity pulls it toward Earth, eventually stopping at its peak and coming back to the ground," said Karen Richon, an engineer Webb Flight Dynamics Principal at NASA's Goddard Space Flight Center in Greenbelt, Maryland, in a statement.
"Like the ball, Webb is slowing down, and if we allow it, it will eventually stop and fall back toward Earth."
And if the Ariane 5 rocket, which lifted Webb into space, had gone even a little faster, the telescope could have gone out of orbit and exposed its mirror and instruments to the sun, if it had had to slow down.
"Ariane 5 targeted Webb so precisely that our first and most critical burn was smaller than we had to plan and design, leaving more fuel for a longer mission," said Richon.
Learn what temperatures the Webb telescope must withstand 0:56
A solar orbit that protects Webb from its heat
While the Hubble Space Telescope orbits the Earth, Webb orbits the Sun.
Webb's orbit will keep the telescope aligned with Earth, as our planet orbits the sun.
This alignment protects the telescope from heat released by the sun, Earth, and even the moon.
It is imperative that the telescope stays cool because it will observe the universe in infrared light and detect the faintest signals from objects in our distant universe.
Since infrared light can be detected as heat, the entire spacecraft must be shielded from bright heat sources.
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The spacecraft includes a five-layer sunshield to protect Webb's gigantic mirror and instruments from the sun's scorching rays, as they must be kept at a very cold temperature of -370°F (-223°C) to function.
The orbit is called the sun-Earth second Lagrange point, or L2.
Lagrange points are named after Joseph-Louis Lagrange.
This 18th-century mathematician solved the "three-body problem," that is, the stable configurations that allow three bodies to orbit each other while remaining in the same relative positions.
The five solutions of the three-body problem are the five Lagrange points, where the gravitational attraction of two masses is equal to the force needed to make a small object, or spacecraft, move with them.
"Using thrust every three weeks or so from small rocket engines aboard Webb, it will stay in orbit around L2, looping around it in a halo orbit once every six months," Richon said. .
A great view of the universe
The L2 point is ideal for Webb because the gravitational forces of the Sun and Earth will basically ensure that the spacecraft doesn't have to use much thrust to stay in orbit.
And it will allow the telescope to have an unobstructed view of the universe, unlike Hubble, which moves in and out of Earth's shadow every 90 minutes.
The Hubble telescope reached a mark of another planet
Webb's position also means that continuous and stable communication between teams on Earth and the space observatory will be possible through the Deep Space Network, made up of three massive antenna ground stations in Australia, Spain and California.
Now that Webb is in orbit, the spacecraft will spend the next five months calibrating its instruments.
The first images captured by the observatory are expected this summer.