December 25th, 2021, marked a scientific milestone with the successful launch of NASA’s James Webb Space Telescope (Webb).
On January 24th, 2022, it arrived at its orbital home: Lagrange point 2, better known as L2. Now, the Webb telescope’s first science images have made their way back to Earth. To say scientists are stoked is an understatement. While everything has (thankfully) gone to plan, this was no easy undertaking. Here’s what the Webb telescope has been up to over the past few months.
December to January: 29 Days on the Edge
After more than 20 years, the James Webb Space Telescope blasted off into orbit on an Ariane 5 rocket from the European Space Agency (ESA) facility at Kourou, French Guiana. But this was just the beginning. Once it slipped the surly bonds of Earth, the Webb had a tension-filled 29-day journey ahead to its L2 home. Many of the parts had to work in sequence and unison to ensure the craft arrived safely and was prepared for the next step of its mission.
For example, 27 minutes after launch, the telescope was released from the Ariane 5 rocket. Within two minutes after separation, its solar array was released and deployed. And 12.5 hours after launch, the telescope executed the first of three mid-course correction (MCC) burns designed to nudge it into L2 orbit without overshooting the Lagrange point, since doing so would require it to turn around and expose critical mission equipment to the full force of the sun.
On the third day, the craft deployed its forward and aft sunshield pallets. After six days, the James Webb Telescope sunshield began opening, and by day 10, sunshield deployment was complete. On January 8th, 2022, the telescope was fully deployed, and on January 24th, it completed its insertion burn for L2 orbit.
January to February: Setting Up Shop
Once at L2, it was time for the Webb to set up shop. This started with cooldown and calibration — making sure instruments cooled down to stable operating temperatures, ensuring that mirrors and other optics were correctly calibrated, and assessing the James Webb Telescope sunshield for any damage or distortion. Day 31 post-launch saw the start of the mirror alignment process, which is broken down into seven stages: segment image identification, segment alignment, image stacking, coarse phasing, fine phasing, telescope alignment over instrument fields of view, and iterative alignment for final correction.
Worth noting: This Lagrange location isn’t entirely stable. Along with cooling and calibration, the telescope must make regular course and attitude corrections to remain at L2. To break it down: L2’s position “behind” the Earth offers the telescope an unfettered look into the darkness of space while allowing it to soak up solar rays for power. It leverages the balanced gravity of the Earth, sun and moon to stay in orbit with minimal effort. However, L2 is an unstable Lagrange point. This means that unlike its counterparts at L4 and L5, course corrections are required every 28 days to keep the telescope in orbit.
February to April: The Webb Telescope’s First Images
Six weeks after the launch of Webb, scientists saw the first photons captured by the telescope and detected with the Near Infrared Camera (NIRCam). Two months post-launch, the segment alignment kicked off, followed by image stacking, phasing, and telescope alignment. Now, the James Webb Telescope is in its final cooling phase before step seven, iterative alignment, which should occur within the next month.
But the Webb also took some time out to snap a few pictures and send them back to Earth. Specifically, the telescope pointed its main mirror at HD 84406 — which, according to a Space.com article, scientists describe as a “boring star” in our galaxy, and one that’s 100 times fainter than what can be seen with the naked eye. However, both its location deep within the Milky Way and its lack of luminesce were ideal to see if Webb could live up to the hype.
Spoiler alert: It did. The first engineering images from the Webb Telescope showed a bright, amber-colored star surrounded by fainter flecks and dots — each one representing a previously unseen galaxy. Also on the list for their moment in the spotlight in the first year of science are Trappist-1E, the Trojan Asteroids and the icy moons Enceladus, Europa and Titan. Scientists hope to see distant galaxies and newborn stars as well.
Put simply? The James Webb Space Telescope has been keeping itself busy over the past few months — and it’s just getting started.
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