Telescopes from the Ground Up

A space telescope gets down to the details

In 1990, the Hubble Space Telescope, named in honor of astronomer Edwin Hubble, was launched into orbit around the Earth.

The telescope, a basic reflector with a 94.5-inch (2.4-meter) mirror, was packed with instruments that would give astronomers clear views of the universe in visible, infrared and ultraviolet light. Without the Earth’s atmosphere blocking its view, Hubble would be able to observe details of astronomical objects that had never been seen before.

Disaster strikes

It was a long-delayed dream about to come true. NASA had started working on Hubble, the first telescope in the Great Observatories program, in 1977. It was originally supposed to be launched in 1985. But then the space shuttle Challenger exploded in 1986, and flights came to a halt while NASA tried to figure out how to safely resume them.

The delay made it difficult to schedule a time to get Hubble into space. Other flights came first. Conditions had to be right. It was years before Hubble finally sped toward space on the space shuttle Discovery.

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Space Telescopes
Diagram showing the orbit of the Hubble Space Telecope around Earth.
Image of the Hubble Space Telescope in orbit.Enlarge picture
The Hubble Space Telescope (HST)
Year launched: 1990
Telescope type: Reflector
Light collector: Aluminum-coated glass mirror
Mirror diameter: 94.5 inches
(2.4 m)
Light observed: Infrared, visible, ultraviolet
Discovery Highlights:
  • Helped determine the age of the universe and the way galaxies form. Revealed extraordinary details about the process by which Sun-like stars end their lives as planetary nebulae.