Editing Space telescope

{{Short description|Instrument in space to study astronomical objects}}
{{More citations needed|date=November 2023}}
[[File:Wavelength Sensitivity of Hubble, Webb, Roman, and Other Observatories (01FEBQTM8Y4FESTQ4N2AFQDBXH).jpg|thumb|upright=1.8|Wavelength sensitivity of Hubble, Webb, Roman, and other major observatories]]
[[File:HST-SM4.jpeg|thumb|The [[Hubble Space Telescope]], one of the [[Great Observatories program|Great Observatories]]]]
A '''space telescope''' (also known as '''space observatory''') is a [[telescope]] in outer space used to observe astronomical objects. Suggested by [[Lyman Spitzer]] in 1946, the first operational telescopes were the American [[Orbiting Astronomical Observatory]], [[OAO-2]] launched in 1968, and the Soviet [[Orion (space telescope)|Orion 1 ultraviolet telescope]] aboard space station [[Salyut 1]] in 1971. Space telescopes avoid several problems caused by the atmosphere, including the absorption or scattering of certain wavelengths of light, obstruction by clouds, and distortions due to atmospheric refraction such as [[twinkling]]. Space telescopes can also observe dim objects during the daytime, and they avoid [[light pollution]] which [[Observatory#Ground-based observatories|ground-based observatories]] encounter. They are divided into two types: Satellites which map the entire sky ([[astronomical survey]]), and satellites which focus on selected [[astronomical object]]s or parts of the sky and beyond. Space telescopes are distinct from [[Earth imaging satellite]]s, which point toward Earth for [[satellite imaging]], applied for [[Weather satellite|weather analysis]], [[Reconnaissance satellite|espionage]], and [[Remote sensing|other types of information gathering]].

== History ==

In 1946, American theoretical astrophysicist [[Lyman Spitzer]], "father of Hubble" proposed to put a telescope in space.<ref>{{cite web |title=Lyman Spitzer - NASA Science |url=https://science.nasa.gov/people/lyman-spitzer-making-space-for-hubble/ |website=science.nasa.gov |access-date=7 January 2024 |language=en}}</ref><ref>{{cite web |title = Hubble Essentials: About Lyman Spitzer, Jr. |publisher = [[Space Telescope Science Institute]] |website = Hubble Site |url = http://hubblesite.org/the_telescope/hubble_essentials/lyman_spitzer.php }}</ref> Spitzer's proposal called for a large telescope that would not be hindered by Earth's atmosphere. After lobbying in the 1960s and 70s for such a system to be built, Spitzer's vision ultimately materialized into the [[Hubble Space Telescope]], which was launched on April 24, 1990, by the [[Space Shuttle Discovery|Space Shuttle ''Discovery'']] (STS-31).<ref>{{cite web |title = Hubble Essentials: Quick Facts |publisher = [[Space Telescope Science Institute]] |website = Hubble Site |url = http://hubblesite.org/the_telescope/hubble_essentials/quick_facts.php }}</ref> This was launched due to many efforts by Nancy Grace Roman, "mother of Hubble", who was the first Chief of Astronomy and first female executive at NASA.<ref>{{Cite web |date=June 4, 2024 |title=The mother of hubble |url=https://esahubble.org/about/history/the-mother-of-hubble/}}</ref> She was a program scientist that worked to convince NASA, Congress, and others that Hubble was "very well worth doing".<ref>{{Cite web |title=Dr. Nancy Grace Roman (1925-2018) - NASA Science |url=https://science.nasa.gov/people/nancy-roman/ |access-date=2024-06-05 |website=science.nasa.gov |language=en-US}}</ref>

The first operational space telescopes were the American [[Orbiting Astronomical Observatory]], [[OAO-2]] launched in 1968, and the Soviet [[Orion (space telescope)|Orion 1 ultraviolet telescope]] aboard space station [[Salyut 1]] in 1971.

== Advantages ==
[[File:NASA's Great Observatories Provide a Detailed View of Kepler's Supernova Remnant.jpg|thumb|[[Kepler's Supernova]] observed in visible light, infrared, and X-rays by NASA's three [[Great Observatories]]]]
Performing [[astronomy]] from [[Observatory#Ground-based observatories|ground-based observatories]] on Earth is limited by the filtering and distortion of [[electromagnetic radiation]] ([[Scintillation (astronomy)|scintillation]] or twinkling) due to the [[Earth's atmosphere|atmosphere]]. A telescope orbiting Earth outside the atmosphere is subject neither to twinkling nor to [[light pollution]] from artificial light sources on Earth. As a result, the [[angular resolution]] of space telescopes is often much higher than a ground-based telescope with a similar [[aperture]]. Many larger terrestrial telescopes, however, reduce atmospheric effects with [[adaptive optics]].<ref name=nasa>{{cite web |title=Why a Telescope in Space? - NASA Science |url=https://science.nasa.gov/mission/hubble/overview/why-a-space-telescope-in-space/ |website=science.nasa.gov |date=13 January 2023 |access-date=7 January 2024 |language=en}}</ref>

Space-based astronomy is more important for frequency ranges that are outside the [[optical window]] and the [[radio window]], the only two wavelength ranges of the [[electromagnetic spectrum]] that are not severely attenuated by the atmosphere.<ref name=nasa/> For example, [[X-ray astronomy]] is nearly impossible when done from Earth, and has reached its current importance in astronomy only due to orbiting X-ray telescopes such as the [[Chandra X-ray Observatory]] and the [[XMM-Newton|XMM-Newton observatory]]. [[Infrared]] and [[ultraviolet]] are also largely blocked by the atmosphere. But in space, there is nothing to resist. So we can get higher resolutions in these wavelengths. To capture them, we have sent James Webb Space Telescope (JWST) and many other telescopes to space.

== Disadvantages ==
Space telescopes are much more expensive to build than ground-based telescopes.  Due to their location, space telescopes are also extremely difficult to maintain.  The Hubble Space Telescope was serviced by the [[Space Shuttle]], but most space telescopes cannot be serviced at all.

== Future of space observatories ==
Satellites have been launched and operated by [[NASA]], [[Indian Space Research Organisation|ISRO]], [[European Space Agency|ESA]], [[China National Space Administration|CNSA]], [[JAXA]] and the [[Soviet space program]] (later succeeded by [[Roscosmos]] of Russia).  As of 2022, many space observatories have already completed their missions, while others continue operating on extended time.  However, the future availability of space telescopes and observatories depends on timely and sufficient funding.  While future space observatories are planned by NASA, JAXA and the [[China National Space Administration|CNSA]], scientists fear that there would be gaps in coverage that would not be covered immediately by future projects and this would affect research in fundamental science.<ref name="NDTV">{{cite web |url = https://www.ndtv.com/science/as-nasas-prized-telescopes-falter-astronomers-fear-losing-their-eyes-in-space-1934035 |last = Kaplan |first = Sarah  |title = As NASA's Telescopes Falter, Astronomers Fear Losing Their Eyes In Space |date = 18 October 2018 |website = NDTV.com |access-date = 19 October 2018 }}</ref>

On 16 January 2023, NASA announced preliminary considerations of several future space telescope programs, including the Great Observatory Technology Maturation Program, [[Habitable Worlds Observatory]], and New Great Observatories.<ref name="SN-20230116">{{cite news |last=Foust |first=Jeff |title=NASA prepares next steps in development of future large space telescope |url=https://spacenews.com/nasa-prepares-next-steps-in-development-of-future-large-space-telescope/ |date=16 January 2023 |work=[[SpaceNews]] |accessdate=24 January 2023 }}</ref><ref name="SA-20230123">{{cite news |last=O'Callaghan |first=Jonthan |title=JWST Heralds a New Dawn for Exoplanet Science - The James Webb Space Telescope is opening an exciting new chapter in the study of exoplanets and the search for life beyond Earth |url=https://www.scientificamerican.com/article/jwst-heralds-a-new-dawn-for-exoplanet-science/ |date=23 January 2023 |work=[[Scientific American]] |accessdate=24 January 2023 }}</ref>

== List of space telescopes ==
{{Main|List of space telescopes}}

== See also ==
* [[Airborne observatory]]
* [[Balloon-borne telescope]]
* [[Earth observation satellite]]
* [[List of telescope types]]
* [[Timeline of artificial satellites and space probes]]
* [[Timeline of telescopes, observatories, and observing technology]]
* [[Ultraviolet astronomy]]
* [[X-ray telescope]]

== References ==
{{Reflist}}

== Further reading ==
* Lyman Spitzer, [https://history.nasa.gov/SP-4407/vol5/chapter-3/III-1%20(546).pdf "Astronomical Advantages of an Extra-terrestrial Observatory"], 1946
* Neil English: ''[https://link.springer.com/book/10.1007/978-3-319-27814-8 Space Telescopes – Capturing the Rays of the Electromagnetic Spectrum]''. Springer, Cham 2017, {{ISBN|978-3-319-27812-4}}.

== External links ==
* {{Commons category-inline|Space telescopes}}·
* [https://nssdc.gsfc.nasa.gov/astro/astrolist.html Space telescopes with frequencies, at GSFC.]

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