The Hubble Space Telescope (also known as HST or Hubble) is a space telescope that was deployed into low-Earth orbit in 1990 and is still operational today. It is not the first space telescope, but it is one of the largest and most flexible, regarded as a crucial scientific instrument as well as a public relations boon for astronomy. The Hubble telescope is one of NASA's Great Observatories and is named after astronomer Edwin Hubble. The Space Telescope Science Institute (STScI) picks Hubble's targets and interprets the accompanying data, while the Goddard Space Flight Center (GSFC) oversees the spacecraft. Hubble has a 2.4 m (7 ft 10 in) mirror, and its five primary instruments look at the electromagnetic spectrum in the ultraviolet, visible, and near-infrared wavelengths.
Hubble's orbit outside of the Earth's distorted atmosphere allows it to collect extraordinarily high-resolution photos with far less background light than ground-based observatories. It has captured some of the most detailed visible-light photographs, giving it a unique perspective into space. Many Hubble observations have led to astrophysics advances, such as calculating the universe's expansion rate. The Hubble telescope was sponsored and developed by the United States space agency NASA with support from the European Space Agency in the 1970s. It was supposed to launch in 1983, but the project was hampered by technical issues, finance issues, and the Challenger catastrophe in 1986. Hubble was launched in 1990, but its main mirror had been ground improperly, causing spherical aberration that limited the telescope's capabilities. A service trip in 1993 restored the optics to their original condition.
Hubble is the only telescope built to be maintained by humans in space. All five of the telescope's principal instruments have been repaired, updated, or replaced thanks to five Space Shuttle trips. Following the Columbia disaster (2003), the fifth mission was initially canceled for safety reasons, but when NASA Administrator Michael D. Griffin approved it, it was completed in 2009. The telescope celebrated its 30th anniversary in April 2020, and it is expected to continue operating until 2030–2040. Along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope, Hubble is part of NASA's Great Observatories program, which focuses on visible light (which covers the infrared bands). The James Webb Space Telescope (JWST), which was launched on December 25, 2021, is Hubble's successor in the mid-IR to the visible spectrum.
Hubble Telescope's conception to design and its goal
Proposals and precursors
Hermann Oberth considered the pioneer of modern rocketry, released Die Rakete Nach Den Planetenräumen ("The Rocket into Planetary Space") in 1923 alongside Robert H. Goddard and Konstantin Tsiolkovsky, describing how a telescope may be launched into Earth orbit by a rocket. The Hubble Space Telescope's history may be traced back to astronomer Lyman Spitzer's 1946 publication "Astronomical advantages of an extraterrestrial observatory." He talked about the two key benefits of a space-based observatory over ground-based telescopes in it.
First, angular resolution (the lowest separation at which objects can be clearly differentiated) would be restricted only by diffraction, rather than turbulence in the atmosphere, which causes stars to twinkle and is referred to as seen by astronomers. At that time ground-based telescopes were restricted to resolutions of 0.5–1.0 arcseconds, compared to a theoretical diffraction-limited resolution of roughly 0.05 arcsec for an optical telescope with a mirror 2.5 m (8 ft 2 in) in diameter. Second, a space-based telescope might see infrared and ultraviolet light, which are absorbed severely by Earth's atmosphere. Spitzer spent much of his career advocating for the creation of a space telescope. A study by the National Academy of Sciences in the United States proposed the building of a space telescope as part of the space program in 1962, and Spitzer was named chair of a group charged with setting scientific objectives for a big space telescope in 1965.
The "Mother of Hubble," Nancy Grace Roman, was also instrumental. She delivered public speeches praising the telescope's scientific significance long before it became an official NASA project. After it was approved, he became the program scientist, forming a steering group to make astronomer needs possible to execute and testifying before Congress during the 1970s to urge for ongoing financing of the telescope. Her expertise as a project scientist influenced the way NASA manages huge scientific initiatives.
Following World War II, scientists began experimenting with space-based astronomy on a modest scale, utilizing advances in rocket technology. The first ultraviolet spectrum of the Sun was collected in 1946, and the Orbiting Solar Observatory (OSO) was launched in 1962 to gather UV, X-ray, and gamma-ray spectra. The United Kingdom launched an orbiting solar telescope as part of the Ariel space program in 1962, and NASA launched the first Orbiting Astronomical Observatory (OAO) mission in 1966. After three days, OAO-1's battery died, and the operation was called off. It was followed by the Orbiting Astronomical Observatory 2 (OAO-2), which conducted ultraviolet studies of stars and galaxies from 1968 to 1972, well beyond its intended one-year mission.
The OSO and OAO missions showed how essential space-based observations may be in astronomy. In 1968, NASA finalized designs for a space-based reflecting telescope with a mirror diameter of 3 m (9.8 ft), dubbed the Large Orbiting Telescope or Large Space Telescope (LST) temporarily, with a launch date of 1979. These plans emphasized the importance of crewed maintenance missions to the telescope in order to ensure that such a costly program had a long working life, and the concurrent development of plans for the reusable Space Shuttle indicated that the technology to allow this was soon to become available.
The search for money
The OAO's continued success sparked a growing agreement among astronomers that the LST should be a primary objective. NASA formed two groups in 1970, one to develop the engineering aspect of the space telescope project and the other to select the mission's scientific aims. After establishing these, NASA's next task was to get money for the device, which would be significantly more expensive than any Earth-based telescope. Many components of the projected budget for the telescope were questioned by the US Congress, which necessitated a reduction in the budget for the planning phases, which at the time consisted of extremely extensive studies of prospective instruments and technology for the telescope. Due to budget constraints in 1974, Congress withdrew all financing for the telescope project. As a result, astronomers organized a countrywide lobbying effort. Many astronomers met with members of Congress and coordinated large-scale letter-writing campaigns. The National Academy of Sciences issued a report underlining the necessity for a space telescope, and the Senate finally agreed to fund half of the funding that Congress had allocated.
The intended mirror diameter was decreased from 3 m to 2.4 m as a result of the financing challenges, both to save money and to allow a more compact and effective arrangement for the telescope components. Budgetary issues forced collaboration with the European Space Agency, and an intended precursor 1.5 m (4 ft 11 in) space telescope to test the equipment to be utilized on the main satellite was scrapped (ESA). In exchange for European scientists receiving at least 15% of the telescope's observation time, ESA committed to fund and supply one of the telescope's first-generation equipment, as well as the solar cells that would power it and employees to work on the telescope in the United States. Congress finally authorized US$36 million in financing for 1978, and work on the LST began in earnest, with a target launch date of 1983. The telescope was named after Edwin Hubble in 1983, when he validated one of the biggest scientific findings of the twentieth century, that the universe is expanding, made by Georges Lemaître.
Comments