The Hubble Space Telescope (HST), named after the astronomer Edwin Hubble, is the first large optical space observatory telescope. Being above the atmosphere, it can view the sky more clearly than any terrestrial telescope due to a lack of atmospheric blur. HST’s main mirror is 2.4 meters across and was constructed in a collaboration from both the US’s National Aeronautics and Space Administration (NASA) and the European Space Agency. The HST orbits the earth at a height of 600 km and was launched on April 24, 1990. Like other things in low Earth orbit, it travels at approximately 10 km per second.

The telescope was launched in 1990 and upon entering orbit, there seemed to be no problem with the telescope’s operation. However, a problem was discovered when it started photographing objects.

When the HST took its first pictures, astronomers were happy to see the images, but they were not as sharp and as crisp as expected. For an initially unknown reason, the pictures were inferior to those taken on Earth. A problem was found with the telescope's mirror in that it was not curved right. Although it was only off by 2.2 microns, this was enough to cause the telescope to send back blurred images.

Another space shuttle was soon sent up to make the painstaking repairs to the telescope. Astronauts were required to install some small mirrors in order to correct the light from the larger mirror, taking five days of space walks. Eventually, Hubble was fixed.

Repairs and servicing missions have been conducted to the Hubble Space Telescope five times since its launch to keep it in orbit and enhance it as newer technology on earth became available.

In its near three decades of use, the Hubble Space Telescope has produced a dazzling array of photographs, and helped astronomers and scientists in other areas shed new light on previously unknown questions. In 2004, Hubble looked back several billion years to the first galaxies in a minute part of space now known as the Hubble Ultra Deep Field. It was able to help settle the age of the universe at about 13.7 billion years. Before the Hubble, scientists could only determine it was between 10 and 20 billion years old. As well as this, the HST took the first picture of a planet outside our solar system, and was able to determine the possible makeup of other planets’ atmosphere.