NASA’s Spitzer Space Telescope is celebrating 15 years since its launch on August 25, 2003. This remarkable spacecraft has made discoveries its designers never even imagined. Here are some key facts about Spitzer:

The Spitzer Space Telescope is one of NASA's Great Observatories, designed to observe the universe in infrared light. It was launched in 2003 with an expected lifetime of 5 years. Spitzer has succeeded beyond our wildest expectations, now routinely observing transiting exoplanets and other interesting astronomical phenomena in its 15th year of operations.

Imagine a place where the weather forecast is always the same: scorching temperatures, relentlessly sunny, and with absolutely zero chance of rain. This hellish scenario exists on the permanent daysides of a type of planet found outside our solar system dubbed an "ultrahot Jupiter."

Thin, red veins of energized gas mark the location of one of the larger supernova remnants in the Milky Way galaxy in this image from NASA's Spitzer Space Telescope.

For the first time, astronomers have directly imaged the formation and expansion of a fast-moving jet of material ejected when the powerful gravity of a supermassive black hole ripped apart a star that wandered too close to the massive monster.

Much like detectives who study fingerprints to identify the culprit, scientists used NASA’s Hubble and Spitzer space telescopes to find the “fingerprints” of water in the atmosphere of a hot, bloated, Saturn-mass exoplanet some 700 light-years away. And, they found a lot of water. In fact, the planet, known as WASP-39b, has three times as much water as Saturn does.

In the year since NASA announced the seven Earth-sized planets of the TRAPPIST-1 system, scientists have been working hard to better understand these enticing worlds just 40 light-years away. Thanks to data from a combination of space- and ground-based telescopes, we know more about TRAPPIST-1 than any other planetary system besides our solar system.

The hottest point on a gaseous planet near a distant star isn’t where astrophysicists expected it to be – a discovery that challenges scientists’ understanding of the many planets of this type found in solar systems outside our own.

An intensive survey deep into the universe by NASA's Hubble and Spitzer space telescopes has yielded the proverbial needle-in-a-haystack: the farthest galaxy yet seen in an image that has been stretched and amplified by a phenomenon called gravitational lensing.

Astronomers and visualization specialists from NASA's Universe of Learning program have combined visible and infrared vision of the Hubble and Spitzer space telescopes to create an unprecedented, three-dimensional, fly-through view of the picturesque Orion Nebula, a nearby star-forming region.

A NASA-led team has found evidence that the oversized exoplanet WASP-18b is wrapped in a smothering stratosphere loaded with carbon monoxide and devoid of water. The findings come from a new analysis of observations made by the Hubble and Spitzer space telescopes.

A super-Earth exoplanet thought to sport lava lakes on its hot side, 55 Cancri e, likely also wears an atmosphere with ingredients similar to Earth's, a new study indicates.

Beneath an elegant office building with a Spanish-style red tiled roof in Pasadena, California, three timeworn storerooms safeguard more than a century of astronomy. Down the stairs and to the right is a basement of wonder.

A deep look back to the early universe by NASA's Spitzer Space Telescope has revealed a surprisingly rowdy bunch of galaxies. Within a large galaxy sample observed 1.5 billion years after the Big Bang, Spitzer witnessed around 15 percent of galaxies undergoing bouts of extreme starmaking, called starbursts.

For the first time, NASA scientists have detected light tied to a gravitational-wave event, thanks to two merging neutron stars in the galaxy NGC 4993, located about 130 million light-years from Earth in the constellation Hydra.

NASA is seeking information from U.S. parties interested in operating the Spitzer Space Telescope with non-NASA funding after March 2019, when NASA financial support ends.

A study finds that giant exoplanets that orbit far from their stars are more likely to be found around young stars that have a disk of dust and debris than those without disks.

One of the most mysterious stellar objects may be revealing some of its secrets at last. Called KIC 8462852, also known as Boyajian’s Star, or Tabby's Star, the object has experienced unusual dips in brightness

Dim objects called brown dwarfs, less massive than the Sun but more massive than Jupiter, have powerful winds and clouds -- specifically, hot patchy clouds made of iron droplets and silicate dust. Scientists recently realized these giant clouds can move and thicken or thin surprisingly rapidly, in less than an Earth day, but did not understand why.

Researchers say in a new study that the TRAPPIST-1 star is quite old: between 5.4 and 9.8 billion years. This is up to twice as old as our own solar system, which formed some 4.5 billion years ago.

How do you visualize distant worlds that you can't see? IPAC's Robert Hurt and Tim Pyle are featured in a new video produced by JPL that highlights how they use scientific data to imagine exoplanets and other astrophysical phenomena.

Astronomers have watched as a massive, dying star was likely reborn as a black hole.

A study combining observations from NASA’s Hubble and Spitzer space telescopes reveals that the distant planet HAT-P-26b has a primitive atmosphere composed almost entirely of hydrogen and helium.

Astronomers have produced a highly detailed image of the Crab Nebula, by combining data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum.

May 3rd, 2017 marks the 5,000th day of NASA's Spitzer Space Telescope mission. This video gives us a detailed look at six of these days, showing how an automated observatory like Spitzer, which is effectively an astronomy robot, spends its time. It’s overall mission design allows for an unprecedented degree of efficiency, allowing it to study the full range of astronomical phenomena including nearby objects in the solar system, stars in our galaxy, and galaxies out to the edge of the observable universe.

Scientists have discovered a new planet with the mass of Earth, orbiting its star at the same distance that we orbit our sun. The planet is likely far too cold to be habitable for life as we know it, however, because its star is so faint. But the discovery adds to scientists' understanding of the types of planetary systems that exist beyond our own.

Astronomers have detected a huge mass of glowing stardust in a galaxy seen when the universe was only 4 percent of its present age. This galaxy was observed shortly after its formation and is the most distant galaxy in which dust has been detected. This observation is also the most distant detection of oxygen in the universe.

NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.

A planet and a star are having a tumultuous romance that can be detected from 370 light-years away. NASA's Spitzer Space Telescope has detected unusual pulsations in the outer shell of a star called HAT-P-2. Scientists' best guess is that a closely orbiting planet, called HAT-P-2b, causes these vibrations each time it gets close to the star in its orbit.

In a first-of-its-kind collaboration, NASA's Spitzer and Swift space telescopes joined forces to observe a microlensing event, when a distant star brightens due to the gravitational field of at least one foreground cosmic object.