Hubble Space Telescope
The Hubble Space Telescope (HST) is a space-based telescope that was launched into low Earth orbit in 1990 and remains in operation. HST was named after the astronomer Edwin Hubble, and is one of the largest and most versatile space telescopes, known for its profound impact on astronomy.
History and Development
- Conception: The idea for HST originated in 1946 when astronomer Lyman Spitzer proposed the concept of placing a telescope in space to avoid atmospheric distortion.
- Design and Construction: The development of HST was a collaborative effort involving NASA, the European Space Agency (ESA), and various contractors. The telescope was built by Lockheed Martin's Space Systems/Astrophysics, with the primary mirror manufactured by Perkin-Elmer.
- Launch: HST was deployed from the Space Shuttle Discovery during mission STS-31 on April 24, 1990.
Features and Capabilities
- Optical Design: HST has a 2.4-meter (7.9 feet) primary mirror, which is part of a Ritchey-Chrétien optical system designed to provide clear images without the distortion caused by Earth's atmosphere.
- Instruments:
- Servicing Missions: HST has undergone several servicing missions by astronauts to repair, upgrade, and replace instruments. These missions have extended its operational life significantly.
Scientific Contributions
- Deep Field Images: HST has produced images like the Hubble Deep Field and Hubble Ultra-Deep Field, revealing the vast number of galaxies in the observable universe.
- Discovery of Exoplanets: While not its primary focus, HST has contributed to the study of exoplanets through observations of their transits across their host stars.
- Cosmic Expansion: HST has refined measurements of the Hubble's Law, providing insights into the rate of expansion of the universe.
Challenges and Overcoming Them
- Initial Issue: After its launch, HST suffered from spherical aberration due to a manufacturing flaw in its primary mirror. This was corrected during the first servicing mission in 1993 with the installation of corrective optics.
- Maintenance: Regular servicing missions have been crucial to maintaining HST's functionality, including the replacement of gyroscopes, solar arrays, and scientific instruments.
Future
While HST's successor, the James Webb Space Telescope, has taken over some of its observational duties, HST continues to operate, with NASA planning to extend its mission as long as it remains scientifically productive and operationally viable.
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