Mashable Debuts exclusively premieres music, videos, artwork, trailers and more. You saw it here first!

A NASA telescope that's expected to launch in 2018 could revolutionize the way humans understand the universe — and a new documentary promises to bring viewers behind the scenes at NASA, revealing the drama and importance of building that brand new eye in the sky.

The James Webb Space Telescope (JWST) — the largest space telescope ever built — is designed to peer deeply into the cosmos, picking up the first light produced by the universe. It should also be able to find and characterize planets circling other stars with the help of ground-based telescopes.

That hunt for alien planets may even lead to the discovery of the first true twin of our home planet.

"We have a shot at finding life for the first time in human history," astronomer Sara Seagar said in a new trailer for Telescope, the Discovery Channel documentary.

The JWST is designed to replace the Hubble Space Telescope, which has been functioning in orbit for more than 25 years. While Hubble looks out at the universe mostly in the ultraviolet and visible wavelengths, JWST will view the cosmos mostly in the infrared — a part of the spectrum invisible to humans.

The James Webb Space Telescope is expected to launch to space in 2018. Image: Northrop Grumman

Building the more than $8 billion telescope hasn't been easy.

Cost overruns and scheduling problems pushed back the expensive telescope's timeline.

Although the current schedule seems to be holding and steady progress is being made toward launch, the really hard work starts when the JWST gets to space. The tennis court-sized spacecraft will be rocketed to its orbit 1 million miles from Earth. Then it will need to deploy its instruments, sunshield and huge mirror perfectly without direct human assistance.

The Hubble telescope was serviced by astronauts on the space shuttle after its launch, keeping it functioning for more than two decades. But because how far it'll be from the planet, the JWST won't have that option.

According to the Discovery Channel, it's a "one strike and you're out" situation — making it all the more important that scientists and engineers get every detail right before launch.

Telescope is set to premiere on the Discovery Channel on Feb. 20 at 9 p.m. ET. The documentary will then air on the Science Channel on Feb. 21 at 9 p.m. ET.