When the James Webb Space Telescope launched on Saturday, it began a multiyear mission to help humankind catch a glimpse of the origins of the universe.

The telescope, equipped with the most sophisticated array of stargazing equipment ever assembled, will be able to peer into the farthest reaches of space, some 13.8 billion light-years away. The data it collects will allow earthbound scientists to better understand the formation of stars and galaxies just after the big bang.

“When the lights turned on in the universe, that’s what Webb is trying to see,” said Paul Geithner, a NASA project manager who worked on the telescope.

Webb is designed to capture more distant light than any of its predecessors, aiming to examine the first stars in the universe.

But the region of space scientists are trying to observe is so far away that only faint traces of light and heat are detectable from Earth.

To overcome this, the $10-billion telescope needs to be able to see through various interstellar objects that would otherwise obstruct its view. Here’s how it works.

The key to Webb’s deep-space vision is its ability to sense infrared light.

As the universe expands, the light waves from the earliest stars and galaxies stretch out. By the time those waves reach us, they’re too long to be seen as visible light. Instead, they appear as infrared — a form of invisible energy we can detect only as heat.

Infrared waves readily pass through clouds made of gas and dust. By taking in infrared light, the telescope can essentially see through objects that would otherwise block its view, much the way X-rays are used to create images of the structures inside a human body.

Past telescopes have been able to capture infrared light, but only in a more limited range of wavelengths. Webb will fill a large gap by detecting light from the earliest stars in the universe.

The heat of the sun can easily interfere with the Webb’s sensitive infrared detector arrays. That’s why it’s equipped with a shield to reflect the heat.

The Webb must also be positioned at a “Goldilocks” location for telescopes, almost 1 million miles from Earth — a spot that, gravitationally speaking, is not too far and not too close.

The Hubble Space Telescope is in orbit 340 miles above Earth’s surface.

If an infrared telescope such as the Webb were in a similar spot, light and heat from the sun, Earth and moon would drown out the faint signals it was designed to detect.

Instead, the Webb will be positioned almost 1 million miles from Earth to a spot known as the second Lagrange point, or L2.

Once it reaches L2, its sun shield will help keep the infrared sensor and other instruments chilled to a temperature of minus-370 degrees.

Webb’s L2 orbit around the sun will be in sync with Earth’s, so it can be in constant communication with its home base.

L2 is one of five points where the gravitational pull of the sun and Earth is balanced enough to allow a small object — such as a satellite — to remain in a fixed orbit.

“It’s easy to get there and easy to orbit there,” Geithner said. L2 “orbits along with the Earth, so over the course of six months, we’ll have access to any point in the sky.”

Thanks to Webb, astronomers will be able to produce images at a higher resolution than was possible with any other infrared telescope before it. The key is Webb’s large mirror, whose 18 hexagonal pieces will help it absorb as much infrared light as possible.

Because infrared light has a wavelength 10 times as wide as visible light, the Webb needed a significantly larger mirror than the Hubble. The result was a gold plated mirror that is 2.7 times larger than its predecessor.

Though older telescopes such as Herschel and Spitzer have used infrared sensors, they weren’t able to deliver the same quality of images with their smaller mirrors.

The Webb’s massive mirror and delicate sun shield means its six-month journey to L2 will be a complex operation.

Once launched, making any physical repairs to the telescope will be impossible. So each step in its deployment must play out perfectly for the mission to succeed.

Because of its size, the Webb must be folded up before it is loaded onto a rocket. In its compact state, it will be safe from the rough shaking it will experience as it leaves Earth’s atmosphere.

Once on course for L2, the Webb will emerge from the rocket. The telescope’s booster will propel it at a speed of 25,000 mph to escape Earth’s gravity.

Then, Webb’s operators at NASA’s mission control will deploy the telescope’s sun shield. Over two weeks, a complex system of pins, gears and cables will unfold and tighten five trash-bag-thin sheets of a material called Kapton with a specialized coating of aluminum and silicon.

After several weeks in space, the mirror will swing open, and the Webb will be fully deployed.

The observatory is expected to begin sending science data back to Earth about six months after deployment.

The Webb’s initial mission to explore the moments after the big bang will last five to 10 years, though if all goes well it could be extended.

Geithner expects the telescope’s contribution to science — and our curiosity — to be profound.

“Some of [Webb’s] greatest discoveries are likely to be answers to questions that no one has yet asked,” he said.