NASA's James Webb Space Telescope is set to orbit the Lagrange point 2 in relation to the Earth and the Sun. But, what does it really mean? Where is Lagrange point 2 located and why is it of note? Explaining the intricacies, the space agency recently tweeted about the orbit that the telescope will follow over the next few months. In the first tweet in a thread, NASA wrote, “So…you've heard that the Webb telescope will be orbiting Lagrange point 2. But what even is that, anyway? And how do you orbit something that isn't an object?"
The space agency clarified Lagrange point in a tweet thread. “Lagrange points refer to locations where the gravitational forces of 2 massive objects — such as the Sun and Earth — are in equilibrium,” NASA said.
In simpler terms, it's the point where the Earth's gravitational pull completely balances out the Sun's much stronger gravity. The James Webb telescope will be orbiting at Sun-Earth Lagrange point 2 (L2) for its mission.
Researchers have plotted James Webb's orbit in such a way that the telescope's sunshield can always face all of these heat and light sources. This will protect James Webb's optics and instruments, which need to stay cold in order to "detect faint heat signals in the universe.”
The telescope can cover a view of half the sky at any given moment. According to NASA, in six months, James Webb will be able to capture the entire sky.
Instead of simply sitting at L2, James Webb is designed to orbit around that point. This is because it is a more efficient way in which the telescope will always have a continuous supply of solar energy for its thermal stability and power generation.
Another reason for choosing the L2 point is that it is "convenient for always maintaining contact with our Mission Operations Center at Space Telescope Science Institute through the Deep Space Network," as per NASA. The James Webb telescope is not alone in its mission. Other observatories also orbit L2 for the same reasons.
James Webb's rocket has recently slowed down during the last lap of the launch. That's because scientists wanted the telescope to slow down and start orbiting at the desired location. Had it been given more power “Webb would have been going too fast when it got to L2, and we would overshoot our desired orbit”.
The rocket engines aboard James Webb will give a thrust every three weeks to keep it stable in its orbit.
James Webb also had to undergo some course-correction burns along the way in order to find the right amount of energy for orbiting around L2.
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