What was the first space telescope?
Quick answer
NASA’s first successful space telescope was the Orbiting Astronomical Observatory 2 (OAO-2), launched on December 7, 1968, which studied stars in ultraviolet light. The most famous is the Hubble Space Telescope, launched in 1990, the first large optical telescope in space.
Why put telescopes in space?
Earth’s atmosphere blurs starlight (that’s why stars twinkle) and blocks many kinds of light, such as ultraviolet, X-rays and much infrared. Above the atmosphere, telescopes get sharper views and can see these hidden wavelengths. Astronomer Lyman Spitzer proposed a large space telescope as early as 1946.
Key space telescopes
| Telescope | Launched | Known for |
|---|---|---|
| OAO-1 | 1966 | Failed after a battery problem |
| OAO-2 | 1968 | First successful space telescope; ultraviolet observations |
| Hubble | 1990 | Stunning visible-light images; measuring the universe’s expansion |
| Compton Gamma Ray Observatory | 1991 | High-energy gamma rays |
| Chandra X-ray Observatory | 1999 | Black holes and exploding stars in X-rays |
| Spitzer | 2003 | Infrared views of dusty regions |
| Kepler | 2009 | Finding thousands of exoplanets |
| James Webb (JWST) | 2021 | Infrared views of the earliest galaxies |
The Hubble story
Hubble’s first images were blurry: its main mirror had been ground to the wrong shape by about 2 micrometers, a fraction of a hair’s width. In 1993, astronauts on a Space Shuttle mission installed corrective optics, like glasses for a telescope. Hubble then delivered some of the most famous images in history, including the “Pillars of Creation.” It was named after astronomer Edwin Hubble, who proved galaxies such as Andromeda lie beyond our own.
James Webb
JWST’s 6.5-meter gold-coated mirror is much larger than Hubble’s 2.4 m. It orbits about 1.5 million km from Earth and sees in infrared, letting it observe galaxies formed only a few hundred million years after the Big Bang.
Satellites made all this possible, starting with Sputnik 1.
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