(CNN) — Back in 1990, just before the first World Wide Web page was published, and the first GPS navigation system was sold for a car, NASA launched a telescope into space.

The hope was for a mission that could last two decades. Now, on Friday, the Hubble Space Telescope turns 25 and it’s still working.

The telescope’s 1.2 million observations from space make clear there’s more to the universe than meets our eyes.

For 25 years, guided from a NASA control center in Maryland, Hubble has looked up from where it orbits 340 miles above the earth and looked into the past, 13.4 billion light years away.

With an accuracy, NASA says, about like shining a laser beam from New York City on a dime, to Washington, D.C. It’s how Hubble found those ultra deep fields when it collected light from a dark spot in space.

The project almost didn’t happen. Hubble had vision problems early on.

“The first images were actually disappointing,” said Jennifer Wiseman, NASA Senior Project Scientist. “They were blurry, they weren’t what we expected, and it turns out there was a problem with the way the mirror was produced.”

Astronauts fixed the problem, and in later visits, updated the telescope. But the last tuneup was six years ago, before the space shuttle program ended.

Now NASA is working on the successor to Hubble, the James Webb Space Telescope hoping it shows us the universe in ways we never even imagined.

The telescope assembly is so delicate that there’s no dust allowed in the clean room. Plans started about the time Hubble launched. NASA plans for Webb to launch in 2018, flying one million miles from earth.

“With this telescope, we’re going to push back in time and see some of the earliest galaxies that formed after the Big Bang,” said NASA astrophysicist Amber Straughn. “That’s the part of space that Hubble can’t see at all.”

NASA says they don’t know how long Hubble will fly — the agency hopes through at least 2020, which would be 10 years longer than originally planned.