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Hubble Space Telescope (HST)

Hubble Space Telescope (HST) mission graphic

Hubble Space Telescope

Phase: Operating

Launch Date: April 24, 1990

Mission Project Home Page -

Program(s):Cosmic Origins

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The Hubble Space Telescope's launch in 1990 sped humanity to one of its greatest advances in the journey to understand the universe. Hubble is a telescope that orbits Earth. Its position above the atmosphere, which distorts and blocks the light that reaches our planet, gives it a view of the universe that typically far surpasses that of ground-based telescopes.

Hubble was serviced by astronauts five times between 1993 and 2009. Each time, its capabilities were enhanced and its life was extended. In 2015 Hubble marked its 25th year of operations. Hubble is currently operating near its scientific peak. NASA plans to operate Hubble at least until 2020 in order to allow 1 year of overlap of science operations with the James Webb Space Telescope.

Hubble is one of NASA's most successful and long-lasting science missions. It has beamed hundreds of thousands of images back to Earth, shedding light on many of the great mysteries of astronomy. Its gaze has helped determine the age of the universe, the identity of quasars, and the existence of dark energy.

Twenty years later Hubble revisits the Eagle Nebula, commonly called the Pillars of Creation. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

Hubble's discoveries have transformed the way scientists look at the universe. Its ability to show the universe in unprecedented detail has turned astronomical conjectures into concrete certainties. It has winnowed down the collection of theories about the universe even as it sparked new ones, clarifying the path for future astronomers. Among its many discoveries, Hubble significantly improved our measurement of the age of the universe. It also played a key role, in conjunction with other observatories, in the discovery of dark energy, a mysterious force that causes the expansion of the universe to accelerate. This discovery was recognized with the 2011 Nobel Prize for Physics.

Hubble has shown scientists galaxies in all stages of evolution, including toddler galaxies that were around when the universe was still young, helping them understand how galaxies form. It found protoplanetary disks, clumps of gas and dust around young stars that likely function as birthing grounds for new planets. It discovered that gamma-ray bursts — strange, incredibly powerful explosions of energy — occur in far-distant galaxies when massive stars collapse. And these are only a handful of its many contributions to astronomy.

The sheer amount of astronomy based on Hubble observations has also helped make it one of history's most important observatories. More than 10,000 scientific articles have been published based on Hubble data.

The policies that govern the telescope have contributed to its incredible productivity. The telescope is an instrument for the entire astronomical community — any astronomer in the world can submit a proposal and request time on the telescope. Teams of experts then select the observations to be performed. Once observations are completed, the astronomers have a year to pursue their work before the data is released to the entire scientific community. Because everyone gets to see the information, the observations have given rise to a multitude of findings — many in areas that would not have been predicted by the telescope’s original proposals. Hubble's success with these policies has helped spread them throughout the astronomical community, and they are becoming common with other observatories.

Last Updated: February 20, 2015

Related Links
  • HubbleSite (STScI) -
  • ESA HST Site -
  • More about Hubble -
  • Hubble on iSat -
  • HST 25th Anniversary Site -
  • ESA-HST 25th Anniversary Site -
  • ESA Hubblecast videos -