After traveling nearly a million miles, the James Webb Space Telescope arrived at its new home on Monday. The arrival of the spacecraft completes another tricky step as scientists on Earth prepare to spend at least a decade with the observatory studying illuminated light from the dawn of time.
The telescope was launched into space on December 25, as astronomers around the world held their breath. But the $10 billion telescope still had to be powered through the first leg of the installation phase. Earlier this month, astronomers resumed breathing as the observatory unfolded its heat shield and deployed its mirrors and other instruments with few surprises — a remarkable feat given the telescope’s new design and technical complexity.
And on Monday around 2:05 p.m. Eastern Time, engineers confirmed that the James Webb Space Telescope had successfully reached its final destination.
The telescope arrived at a location beyond the moon after a final five-minute firing of the spacecraft’s thrusters, sliding itself into a small pocket of stability where the gravitational forces of the sun and Earth mingle. From this outpost, the second Lagrange Point, or L2, the Webb telescope will be towed next to Earth for years around the sun to monitor space without consuming much fuel to maintain its position.
“We are one step closer to unraveling the mysteries of the universe,” NASA administrator Bill Nelson said in a statement. “And I can’t wait to see Webb’s first new look at the universe this summer!”
NASA officials will speak about what’s next for the spacecraft on the agency’s YouTube channel at 3 p.m., or in the video player above, and another conference is scheduled for 4 p.m.
Named after a former NASA administrator who oversaw the early years of the Apollo program, the James Webb Space Telescope is seven times more sensitive than the nearly 32-year-old Hubble Space Telescope and three times the size. The Webb, a sequel to Hubble, is designed to look further into the past than its celebrated predecessor to study the first stars and galaxies that twinkled alive at the dawn of time, 13.7 billion years ago.
Webb’s Christmas morning launch capped off a risky 25-year development timeline riddled with technical challenges, errors and cost overruns that made the journey to space all the more nerve-wracking for astronomers and space agency managers. The telescope, tightly bundled to fit a European Ariane rocket, unfolded dozens of mechanical limbs and instruments. These included five layers of a thin, foil-like plastic stretched taut to the size of a tennis court to protect Webb’s instruments from the heat of the sun. Later, the telescope unfolded an array of 18 gold-plated mirrors 5 meters wide that will help reflect light from the cosmos into its ultra-sensitive infrared sensors.
The instrument side of the telescope, facing away from the sun, will be shrouded in frigid darkness, while the other side, or the outermost layer of the sunshade, will deflect temperatures as high as 230 degrees Fahrenheit. This helps accomplish a key challenge in Webb’s design of keeping the telescope’s sensors cool so that stray heat doesn’t interfere with infrared scans of ancient galaxies, distant black holes and planets orbiting other stars.
Placing the telescope in the L2 neighborhood will also help keep temperatures down while providing enough sunlight for the Webb’s solar panels, which generate electricity. But the telescope isn’t parked exactly on L2 — it will rotate around the center of the point to expose its solar panels to sunlight.
“If we were perfect there, Earth would block us from getting our electricity,” said Scott Willoughby, the telescope’s program manager at Northrop Grumman, the observatory’s prime contractor. “So we’re doing this halo job.”
Stationing the spacecraft at this distance from Earth also conserves the limited fuel supply.
“If you’re trying to stay closer, you’re going to have to burn fuel to stay there,” Mr Willoughby said. But less fuel is needed to station the Webb on L2, he said, “which means the life of this vehicle will be the longest.” This month, a mission official suggested the spacecraft could remain operational for up to 20 years.
With the telescope’s instruments deployed and the arrival at L2 complete, there are months of smaller strides ahead before those of us on Earth can begin to see the spacecraft’s vivid images of the cosmos. Over the next three months, engineers will watch as algorithms help refine the position of the Webb’s mirror segments, correcting any misalignments — as accurate as a 10,000th of a hair follicle — to leave the 18 hexagonal pieces in its array. function as a single mirror.
Engineers will then need to calibrate the Webb’s scientific instruments, test its ability to lock onto known objects and track moving targets before astronomers can use the telescope for science operations starting this summer.