Hubble Space Telescope

• Context (TH): NASA celebrates 35 years of the Hubble Space Telescope (HST).

About Hubble Space Telescope

• Lyman Spitzer envisioned a space telescope in the 1940s for unobstructed views of the universe.
• NASA and the US Congress approved the Large Space Telescope project in 1969. European Space Agency (ESA) contributed 15% of funding and gained 15% of observation time.
• Later, the HST was planned by NASA in 1979 as an astronomical observatory. Originally scheduled for 1986, it was delayed due to the Space Shuttle Challenger disaster and technical issues.
• Finally launched on April 24, 1990. It was named after the American astronomer Edwin Hubble, whose research in the 1920s provided the first evidence of the universe’s expansion.
• The telescope orbits approximately 547 kilometres above the Earth’s surface.
• It is equipped with a 2.4-meter primary mirror and advanced scientific instruments that allow it to capture high-resolution images and spectroscopic data across the electromagnetic spectrum.
• The primary objectives of the Hubble Space Telescope are to explore the universe and to study its composition, formation, and evolution.

Source: TH

Key Instruments and Upgrades

• Initial Payloads: Included Wide-Field and Planetary Camera (WFPC), Faint Object Camera, GHRS, FOS, a high-speed photometer and three Fine Guidance Sensors.
• COSTAR Installation (1993): Corrected early mirror defect with a set of compensatory mirrors; WFPC replaced with WFPC 2.
• Instrument Replacements (1997): GHRS and FOS were replaced with the Space Telescope Imaging Spectrograph to capture ultraviolet to infrared light frequencies.
• Data Capacity: Transmits ~150GB data per week; made 1.6 million observation of ~52,000 stellar objects.

Major Scientific Contributions

• Cosmic Expansion and Universe’s Age: Identified over 800 Cepheid variable stars in 24 galaxies to estimate the universe’s age at 13.8 billion years through luminosity and pulsation data.
• Redshift and Blueshift Insights: Analysed wavelength changes in light (redshift for moving away, blueshift for approaching) to measure cosmic motion and distances.
• Gamma-Ray Burst Discovery: Located the origin of gamma-ray bursts in star-forming galaxies low in heavier elements.
• Black Hole Evidence: Observations confirmed the presence of supermassive black holes at the centres of many galaxies.
• Dark Matter Mapping: Helped construct a 3D map of dark matter using light distortions from galaxies.
• Technological Blueprint: Served as a model for advanced telescopes like James Webb Space Telescope and upcoming missions.

Iconic Observations and Celestial Discoveries

• Tarantula Nebula (30 Doradus): Captured merging star clusters in the Large Magellanic Cloud, 170,000 light-years away.
• Butterfly Nebula Imaging: Revealed gas dynamics and stellar mechanics using near-ultraviolet to near-infrared wavelengths.
• Globular Cluster NGC 6355: Studied dense, spherical star formations in the Milky Way’s inner region, ~50,000 light-years away.

Also refer to Rate of Universe’s Expansion > Hubble Constant.