The Hubble Telescope

Images and Facts

The giant Telescope was carried into orbit in April 1990 and is a calloboration between NASA and the European Space Agency. The hubble project was funded as far back as the 1970's and was set to be launched in 1983 but unforseen circumstances such as budget issues and the Challenger disaster (see Missions page) put the launch on hold. When finally launched in 1990, there was another major set-back. Technicians discovered that the telescope had trouble focusing and this was the result of the main mirror being ground incorrectly. The telescope would not be repaired until a servicing mission was launched in 1983.

There have been five servicing missions, the last occurring in May 2009. Servicing Mission 1 took place in December 1993 when Hubble's imaging flaw was corrected. Servicing missions 2, 3A, and 3B repaired various sub-systems and replaced many of the observing instruments with more modern and capable versions. However, following the 2003 Columbia disaster, (see Missions page) the fifth servicing mission was canceled on safety grounds. The fifth and final servicing mission eventually launched in May 2009 which saw the installation of two new instruments. Testing of this new equipment meant that the telescope will remain off-line until September 2009. This new epuipment should allow the Hubble to function until at least 2014 when the telescope is due to be taken out of service. The Hebble telescope is due to be replaced by the James Webb Space Telescope.

Facts about the Hubble

  • Named after American astronomer Edwin P Hubble (1889 - 1953)
  • Launched in April 1990 from space shuttle Discovery
  • Mission duration = 20 years
  • Servicing mission 1: December 1993 (repaired the mirror)
  • Servicing mission 2: February 1997
  • Servicing mission 3A: December 1999
  • Servicing mission 3B: February 2002
  • Servicing mission 5: May 2009 (which included the installation of new equipment)
  • Size: Length 43.5 ft (13.2 m), Weight 11,110 kg (24,500 lb), Diameter 14 ft (4.2 m)

Important Discoveries

According to NASA, "Hubble played a key role in discovering that a mysterious form of energy called dark energy is acting like a cosmic gas pedal, accelerating the universe's expansion rate. Dark energy shoves galaxies away from each other at ever-increasing speeds and works in opposition to gravity." Hubble's observations of supernovas helped reveal that the mysterious energy is a constant presence in the universe. (sourced from

One of Hubble's key duties was to help astronomers determine a precise age for the universe. The telescope helped astronomers accomplish that goal, narrowing the universe's age to 13 to 14 billion years old, an accuracy of about 10 percent. Astronomers made observations of Cepheid variable stars, pulsating stars used to measure vast distances, in the Virgo and other clusters to establish the expansion rate and the universe's age.

According to NASA, "Hubble provided astronomers with a 'scrapbook' full of snapshots of the early universe including pictures of the 'deep' universe in a series of unique observations: the Hubble Deep Fields, the Great Observatories Origins Deep Survey, and the Hubble Ultra Deep Field (pictured left). The observations provided the deepest views of the cosmos in visible, ultraviolet, and near-infrared light." Astronomers using ground-based telescopes to hunt for planets outside our solar system, dubbed extrasolar planets, have nabbed more than a hundred alien worlds. But they needed the keen 'eye' of Hubble to make the first direct measurement of the chemical makeup of an extrasolar planet's atmosphere.

The telescope detected the elements sodium, hydrogen, carbon, and oxygen in the atmosphere of a Jupiter-size planet. The unique observation demonstrates that Hubble and other telescopes can sample the chemical makeup of the atmospheres of alien worlds." The Hubble Telescope also detected that the core of most galaxies contain a Black Hole which devours everything within its vicinity. These Black Holes are said to have a mass of millions to billions times that of our sun.

More Facts about Hubble

  • Cost at launch = $1.5bn
  • Spaceflight statistics:
    1. Orbit: 353 miles or 569 km
    2. Time to complete one orbit: 97 minutes
    3. Speed: 17,500 mph (28,000 kph)
  • Optical Capabilities:
    1. Cannot observe the Sun or Mercury as it is too close to the Sun
    2. First image: May 20, 1990: Star Cluster NGC 3532
  • Power
    1. Powered by the sun via 25 foot solar panels
    2. 2,800 watts

In order to take images of distant, faint objects, Hubble must be extremely steady and accurate. The telescope is able to lock onto a target without deviating more than 7/1000th of an arcsecond, or about the width of a human hair seen at a distance of 1 mile.

Looking into the past

When we see images of distant gallaxies captured by Hubble, we do not see them as they are today, but as they were millions of years ago. This is caused by the Speed of Light. The speed of light has been measured at 300,000 kilometers per second and distances in space are so vast that instead of using miles or kilometers to measure the distances between objects, astronomers use light years. A light year is the distance that light travels in one year. If something happens in a galaxy that is 1 million light years away, it would take 1 million years for people on Earth to witness it.