Hubble Space Telescope Timeline

(April 24, 1990 – Present)

The Hubble Space Telescope is a NASA-ESA observatory launched in 1990 that orbits Earth above the atmosphere's distortion. Despite an initial flawed mirror corrected by astronauts in 1993, Hubble has revolutionized astronomy with stunning images and discoveries about the universe's age, expansion, black holes, and distant galaxies. More Less

Go to: Timeline | Event List | Key Facts | Directory

Origins and Planning

Lyman Spitzer proposes a space telescope

1946

Astronomer Lyman Spitzer authored a report advocating for a large telescope in space, arguing it could observe the universe free from Earth's atmosphere. His vision laid the intellectual foundation for what would eventually become the Hubble Space Telescope.

Image source: Lyman Spitzer

NASA and ESA agree to jointly build a space telescope

1977

NASA secured congressional funding for the Large Space Telescope project, with the European Space Agency joining as a partner contributing instruments and solar panels in exchange for observing time. The mission was later renamed the Hubble Space Telescope.

Image source: Hubble Space Telescope

NASA and ESA agree to jointly build a space telescope

Construction of Hubble's primary mirror completed

1981

Perkin-Elmer Corporation finished grinding and polishing Hubble's 2.4-meter primary mirror to extraordinary precision. Tragically, a testing error left the mirror's edge too flat by a fraction of a human hair, a flaw that would later require corrective optics.

Great Observatories program concept established

1985

NASA formalized its Great Observatories program, positioning Hubble alongside future missions like Compton, Chandra, and Spitzer to observe the universe across multiple wavelengths, with Hubble serving as the flagship visible-light observatory.

Image source: Great Observatories program

Space Shuttle Challenger disaster delays Hubble launch

Jan 28, 1986

The destruction of the Space Shuttle Challenger grounded the shuttle fleet for nearly three years, postponing Hubble's planned launch. During the delay, engineers performed extensive testing and improvements on the telescope while it was stored in a clean room.

Image source: Space Shuttle Challenger disaster

Launch and Early Operations

Hubble Space Telescope launched aboard STS-31

Apr 24, 1990

The Space Shuttle Discovery carried Hubble into orbit at an altitude of about 540 kilometers. The following day, astronauts deployed the telescope from the shuttle's cargo bay, beginning its journey as humanity's premier observatory above the atmosphere.

Image source: STS-31

Spherical aberration discovered in Hubble's mirror

Jun 1990

After initial images came back disappointingly blurry, scientists diagnosed spherical aberration caused by the misfigured primary mirror. The flaw limited Hubble's capabilities and became an embarrassment for NASA, prompting plans for a repair mission.

Servicing Missions

First servicing mission corrects Hubble's vision

Dec 2, 1993 - Dec 13, 1993

Astronauts aboard the Space Shuttle Endeavour installed corrective optics (COSTAR) and replaced the Wide Field and Planetary Camera during an ambitious eleven-day mission. The repair restored Hubble's promised sharpness, marking one of NASA's greatest triumphs.

Image source: STS-61

Second servicing mission upgrades instruments

Feb 11, 1997 - Feb 21, 1997

Discovery astronauts replaced the Goddard High Resolution Spectrograph and Faint Object Spectrograph with new instruments, including the Space Telescope Imaging Spectrograph, extending Hubble's infrared and imaging capabilities.

Image source: STS-82

Third servicing mission replaces gyroscopes

Dec 19, 1999 - Dec 27, 1999

After gyroscopic failures forced Hubble into safe mode, Discovery astronauts conducted an urgent repair mission, replacing all six gyroscopes along with a fine guidance sensor and computer upgrades, restoring the telescope to full operation.

Image source: STS-103

Fourth servicing mission installs ACS

Mar 1, 2002 - Mar 12, 2002

Columbia astronauts installed the Advanced Camera for Surveys, which dramatically increased Hubble's discovery efficiency, and replaced the solar arrays with smaller, more powerful ones, giving the telescope renewed vigor.

Image source: STS-109

Fifth and final servicing mission

May 11, 2009 - May 24, 2009

Atlantis astronauts performed the most ambitious upgrade yet, installing Wide Field Camera 3, repairing the Advanced Camera for Surveys and Space Telescope Imaging Spectrograph, and adding new batteries and gyros, extending Hubble's life well into the 2020s.

Image source: STS-125

Scientific Discoveries

Hubble Key Project refines Hubble constant

1994 - 1999

Hubble's multi-year Key Project measured Cepheid variable stars in nearby galaxies to precisely determine the rate of cosmic expansion, pinning down the age of the universe at approximately 12 to 14 billion years.

Image source: Hubble's law

Hubble Key Project refines Hubble constant

Comet Shoemaker-Levy 9 impacts Jupiter observed

Jul 16, 1994 - Jul 22, 1994

Hubble provided spectacular images of comet fragments slamming into Jupiter, creating Earth-sized fireball scars in the planet's atmosphere. The event demonstrated Hubble's unique ability to capture dynamic phenomena across the solar system.

Image source: Comet Shoemaker–Levy 9

Hubble Deep Field observations begin

Dec 18, 1995 - Dec 28, 1995

Hubble stared at a tiny, seemingly empty patch of sky for ten consecutive days, revealing thousands of previously unseen galaxies. The Hubble Deep Field revolutionized astronomy by showing that the early universe was densely populated with forming galaxies.

Image source: Hubble Deep Field

Evidence for supermassive black holes compiled

1997

Using Hubble observations, astronomers confirmed that supermassive black holes reside at the centers of many galaxies, including compelling evidence from gas dynamics near galactic cores. This work cemented the link between black holes and galaxy evolution.

Image source: Supermassive black hole

Accelerating expansion of universe confirmed

1998

Two teams using Hubble observations of distant supernovae discovered that the universe's expansion is speeding up, implying the existence of dark energy. The finding earned the 2011 Nobel Prize in Physics and transformed cosmology.

Image source: Accelerating expansion of the universe

Atmosphere of exoplanet HD 209458 b analyzed

Nov 27, 2001

Hubble detected sodium in the atmosphere of an exoplanet transiting its star, the first direct detection of an exoplanet's atmosphere. This pioneering observation opened the field of comparative exoplanetology.

Image source: HD 209458 b

Hubble Ultra-Deep Field reveals earliest galaxies

Sep 24, 2003 - Jan 16, 2004

Hubble accumulated roughly one million seconds of exposure on a small region of the constellation Fornax, producing the deepest image of space ever taken at the time. It revealed galaxies dating back to within a few hundred million years of the Big Bang.

Image source: Hubble Ultra-Deep Field

Pluto's moons Nix and Hydra discovered

Jun 15, 2005

Using Hubble imagery, astronomers discovered two small moons orbiting Pluto beyond Charon. The discovery expanded understanding of the Pluto system ahead of the New Horizons flyby and revealed the complexity of Kuiper Belt objects.

Image source: Nix (moon)

Hubble Frontier Fields program begins

Nov 2013

Hubble began using massive galaxy clusters as natural gravitational lenses to magnify extremely distant background galaxies, pushing observations closer to the era of first galaxy formation than ever before.

Image source: Hubble Space Telescope

Water vapor found on exoplanet atmosphere

Dec 3, 2013

Hubble spectroscopy revealed clear evidence of water vapor in the atmosphere of the exoplanet Tau Boötis b, demonstrating the telescope's power to probe the chemical composition of worlds light-years away.

Image source: Tau Boötis b

Hubble measures universe expansion discrepancy

Apr 25, 2019

Hubble measurements of nearby Cepheids and supernovae refined the local expansion rate with high precision, deepening the 'Hubble tension' — a significant mismatch between local measurements and those inferred from the cosmic microwave background.

Image source: Hubble's law

Hubble observes interstellar comet Borisov

Oct 12, 2019

Hubble captured detailed images of 2I/Borisov, only the second known interstellar object to visit our solar system, providing unprecedented views of material originating from another star system.

Image source: 2I/Borisov

Hubble captures Comet ATLAS breakup

Apr 2020

Hubble documented the dramatic disintegration of Comet ATLAS into dozens of fragments, offering rare insight into how comets die and providing clues about the structure of cometary nuclei.

Image source: C/2019 Y4 (ATLAS)

Legacy and Future

Hubble data contributes to Nobel Prize in Physics

Oct 4, 2011

Saul Perlmutter, Brian Schmidt, and Adam Riess received the Nobel Prize for the discovery of the accelerating universe, a breakthrough enabled substantially by Hubble's precise supernova distance measurements.

Image source: List of Nobel laureates in Physics

Hubble Legacy Field mosaic released

May 2, 2019

Astronomers assembled nearly 7,500 exposures taken over 16 years into a single panoramic portrait containing roughly 265,000 galaxies, stretching back 13.3 billion years — a monumental legacy dataset for future research.

Image source: Hubble Legacy Field

Hubble celebrates 30 years in orbit

Apr 24, 2020

Three decades after launch, Hubble had made over 1.4 million observations and contributed to more than 16,000 scientific papers. NASA celebrated the anniversary despite the pandemic, highlighting the telescope's enduring scientific and cultural impact.

Payload computer malfunction halts science operations

Jun 13, 2021 - Jul 15, 2021

Hubble entered safe mode after its payload computer stopped responding. Engineers spent weeks diagnosing the issue before identifying a faulty power control unit, successfully switching to backup hardware and resuming full science operations.

James Webb Space Telescope launched as successor

Dec 25, 2021

NASA launched the James Webb Space Telescope, designed to complement and extend Hubble's work with powerful infrared observations. Rather than replacing Hubble, Webb joined it in a continuing partnership exploring the cosmos.

Image source: James Webb Space Telescope

Key Facts

Hubble was launched aboard the Space Shuttle Discovery on April 24, 1990, as a joint project between NASA and the European Space Agency (ESA).
Shortly after launch, scientists discovered its primary mirror had a spherical aberration flaw, which was famously corrected during a 1993 Space Shuttle servicing mission.
Astronauts serviced and upgraded Hubble five times between 1993 and 2009, installing new instruments like the Wide Field Camera 3 and repairing key systems.
Hubble observations helped determine the universe's age at approximately 13.8 billion years and provided key evidence for the accelerating expansion of the universe driven by dark energy.
Its Deep Field images revealed thousands of galaxies in tiny patches of sky, transforming our understanding of galaxy formation and evolution.

Source

This Hubble Space Telescope timeline was generated with the help of AI, using information found on the internet.

We work hard to keep these timelines accurate, but mistakes do get through. If you spot one, email us at [email protected] and we'll fix it for future visitors.

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