synonymhubble space telescope (Hubble Space Telescope) generally refers to the Hubble Space Telescope (developed and launched by the United States in 1990)
Hubble Space Telescope(English: Hubble Space Telescope, abbreviation: HST)American astronomersEdwin HubbleIt was successfully launched on April 24, 1990Optical telescope[1]。
The Hubble Telescope was developed by NASA. Its main mirror is 2.4 meters long, and it orbits the earth at the speed of 28000 km/h.As of 2015, although the cumulative cost of the Hubble telescope has reached $10 billion, its achievements have far exceeded expectations.During its service, it not only helped astronomers solve some long-term puzzles, but also led the astronomical community to explain some phenomena with new theories, promoted the progress of astronomical science, and fundamentally changed human understanding of the universe and celestial bodies[22]。
In May 2019, the scientists of the Hubble Space Telescope released the latest cosmic photograph, the "Hubble Heritage Field" (HLF), which is the most complete and comprehensive cosmic map ever. It is a mosaic of 7500 starry photos taken by Hubble in 16 years, including about 265000 galaxies, some of which are at least 13.3 billion years old,Studying it will help scientists understand the earlier history of the universe.[2]
On June 19, 2021, according to Agence France Presse, NASA said that the Hubble Space Telescope, which has been observing the universe for more than 30 years, was shut down in the past few days because a payload computer stopped working since the 13th.[16]
The Hubble Space Telescope (HST) is an astronomerEdwin HubbleA telescope in Earth orbit.The Hubble telescope receives instructions from the ground control center (in Hopkins University, Maryland, USA) and transmits various observation data back to the earth by radio.Because it is located above the earth's atmosphere, it has the advantages that ground-based telescopes do not have: the image is not disturbed by atmospheric turbulence, the visibility is excellent, and there is no background light caused by atmospheric scattering. It can also observe ultraviolet rays that will be absorbed by the ozone layer.Launched in 1990, it has become the most important instrument in the history of astronomy.It has successfully made up for the shortage of ground observation, helped astronomers solve many basic problems in astronomy, and made people have more understanding of astrophysics.In addition, Hubble's ultra deep space field of view is the deepest and most sensitive space optical image available to astronomers.
The Hubble Space Telescope, the Compton Gamma Ray Observatory, the Chandra X-ray Observatory and the Spitzer Space Telescope are all part of the NASA Large Orbital Observatory program.The Hubble Space Telescope is jointly managed by NASA and ESA.
Development history
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theoretical basis
The history of the Hubble Space Telescope can be traced back to the paper "Astronomical Observation Advantages Beyond Earth" proposed by astronomer Lyman Spitzer (Jr.) in 1946.In the article, he pointed out that there are two performances of observatories in space that are better than those on the ground.First of all, the limit of angular resolution (the minimum separation angle that an object can be clearly resolved) will be limited only by diffraction, rather than the visibility caused by the atmosphere that causes twinkling stars and turbulence.At that time, the analytical power of ground-based telescopes was only 0.5-1.0 arc seconds, compared with the theoretical diffraction limit of 0.1 arc seconds for a 2.5 meter aperture telescope.Secondly, telescopes in space can observe infrared and ultraviolet rays absorbed by the atmosphere.[4]
Spitzer takes space telescope as his career and devotes himself to the promotion of space telescope.In 1962, the National Academy of Sciences recommended space telescope as a part of the space development plan in a report. In 1965, Spitzer was appointed as the chairman of a scientific committee whose purpose was to build a space telescope.
During the Second World War, scientists used to develop rocket technology, and at the same time, they once tried space based astronomy on a small scale.In 1946, the ultraviolet spectrum of the sun was observed for the first time.In 1962, Britain launched a solar telescope and placed it in orbit as part of the Aryan space program.In 1966, NASA carried out the first orbital observatory (OAO) mission, but the battery of the first OAO failed three days later, and the mission was suspended.The second OAO made ultraviolet observations of stars and galaxies from 1968 to 1972, which lasted one year longer than the original plan.
The orbital observatory mission demonstrated the important role of space-based observatories in astronomy. Therefore, in 1968, NASA decided to build a 3 meter diameter reflecting telescope in space. At that time, it was temporarily called the Large Orbital Telescope or the Large Space Telescope (LST), which was expected to be launched in 1979.This plan emphasizes the need for someone to go into space for maintenance to ensure that this expensive plan can last long enough working hours;And the space shuttle technology that can be reused should be developed synchronously, so that the previous plan can become a feasible plan.
preparation in advance
The success of the orbital observatory project has encouraged more and more public opinion to support that large space telescopes should be an important goal in the field of astronomy.In 1970, NASA set up two committees, one to plan the space telescope project and the other to study the scientific objectives of space telescope missions.After that, the next obstacle that NASA needs to remove is the problem of money, because it is many times more expensive than any ground-based observatory.The Congress of the United States raised many doubts about the budget requirements of space telescopes. In order to fight against the budget required for disarmament, it listed the hardware requirements of telescopes and the instruments needed for subsequent development in detail at that time.In 1974, encouraged by government spending cuts, Gerald Ford eliminated all budgets for space telescopes.
In response, astronomers coordinated nationwide lobbying efforts.Many astronomers went to visit the House of Representatives and senators in person, and carried out large-scale letters and word propaganda.The report published by the National Academy of Sciences also emphasized the importance of space telescopes. Finally, the Senate decided to restore half of the budget originally deleted by Congress.
The reduction of funds has led to the reduction of target projects, and the aperture of lenses has also been reduced from 3 meters to 2.4 meters, in order to reduce costs and more effectively and closely configure the hardware of the telescope.As an early test, the 1.5 meter space telescope placed on the satellite was also cancelled. The European Space Agency (ESA), which expressed concern about the budget, has also become a cooperative partner.The European Space Agency has agreed to provide funds and some instruments needed for telescopes, such as solar cells as power sources, in return for European astronomers to spend at least 15% of their observation time with telescopes.In 1978, the US Congress allocated US $36000000 for the design of a large space telescope, which was scheduled to be launched in 1983.
In early 1980, the telescope was named Hubble in memory of Edwin Hubble, an astronomer who discovered the expansion of the universe in the early 20th century.
Design and manufacture
In May 1979, the Hubble primary mirror was polished at Perkin Elmer Company in Danbury, Connecticut.Dr. Martin Yelin, an engineer who works for the company, appears in the picture.
Once the space telescope plan was approved, it was divided into many sub plans and sent to various agencies for implementation.Marshall Space Flight Center (MSFC) is responsible for the design, development and construction of telescopes, and Goldstone Space Flight Center (GSFC) is responsible for the overall control of scientific instruments and the mission control center on the ground.The Marshall Space Flight Center commissioned Perkin Elmer to design and manufacture the optical components of the space telescope, as well as the precision positioning sensor (FGS). Lockheed was commissioned to build the spacecraft for installing the telescope.
Combined installation of optical telescope (OTA)
The mirror and optical system of the telescope are the most critical parts, so there are very strict specifications in the design.For ordinary telescopes, the accuracy of the mirror after polishing is about one tenth of the wavelength of visible light. However, because the observation range of space telescopes is from ultraviolet light to near-infrared light, it requires ten times higher resolution than previous telescopes. The accuracy of its mirror after polishing is one twentieth of the wavelength of visible light, that is, about 30 nanometers.
Perkin Elmer deliberately used an extremely complicated computer-controlled polishing machine to grind the mirror, but there was a problem in the cutting-edge technology;Kodak was commissioned to use traditional polishing techniques to make a spare mirror (Kodak's mirror is now permanently stored in the Smithsonian Institute).In 1979, Perkin Elmer began to grind lenses using ultra-low expansion glass. In order to minimize the weight of the mirror, honeycomb lattice was used. Only one inch of the surface and one inch of the bottom were thick glass.
The polishing of mirrors started in 1979 and lasted until May 1981. The progress of polishing had fallen behind and exceeded the budget, when NASA's report began to question Perkin Elmer's management structure.To save money, NASA stopped supporting the production of lenses and postponed the launch date to October 1984.The lenses were completed at the end of 1981, and were plated with 75 nm thick aluminum enhanced reflection and 25 nm thick magnesium fluoride protective layer.
Because the budget of the optical telescope combination continues to expand and the progress is lagging behind, the question of whether Perkin Elmer is competent for the follow-up work continues to exist.In response to what has been described as "an unsettled and fickle daily report", NASA extended the launch date to April 1985.However, Perkin Elmer's progress has continued to increase by one month every quarter, and the time delay has also reached the point where every working day is falling behind.NASA was forced to postpone the launch date, first to March 1986 and then to September 1986.By this time, the total cost of the whole plan had reached $1.175 billion.
Space platform system
Spacecraft with telescopes and instruments is another major engineering challenge.It must be capable of withstanding the temperature changes caused by frequent entry and exit between the sun and the earth's shadow, and be extremely stable and able to accurately target the telescope for a long time.The shield made of multi-layer insulating materials can keep the temperature inside the telescope stable, and the light aluminum shell surrounds the support of the telescope and instrument.Inside the housing, the graphite epoxy frame firmly fixes the calibrated working instrument.
For a period of time, the construction of the spaceship used to place instruments and telescopes was smoother than the combination of optical telescopes, but Lockheed still experienced budget shortfalls and progress lags. Before the summer of 1985, the progress of the spaceship was months behind, and the budget exceeded 30%.The report of Marshall Space Flight Center believes that Lockheed did not take the initiative in the construction of spacecraft and relied excessively on the guidance of NASA.
Ground support
In 1983, the Space Telescope Science Association (STSCI) was established after the power struggle between NASA and the scientific community.The Space Telescope Science Association is affiliated to the American University Astronomical Research Alliance (AURA), which is a unit composed of 32 American universities and 7 international members. Its headquarters is located on the campus of Johns Hopkins University in Baltimore, Maryland.
The Space Telescope Science Association is responsible for the operation of space telescopes and the delivery of data to astronomers.The National Aeronautics and Space Administration (NASA) wants to use it as an internal organization, but scientists plan to establish it as a research unit according to the practice of the scientific community. NASA's Goddard Space Flight Center located at Green Causeway, Maryland, 48 kilometers south of the Space Telescope Science Association and contractors provide engineering support.The Hubble telescope operates 24 hours a day, and four working teams take turns to operate it.
The European Space Telescope Coordination Agency was established in Garching bei M ü nchen, Germany, near Munich, in 1984 to provide similar support to European astronomers.
Free floating black hole
In June 2022, according to the Science and Technology Daily and the website of Forbes Biweekly, the research teams from the Space Telescope Science Institute of the United States and the University of California, Berkeley, respectively, independently published papers that they used the Hubble Space Telescope of the National Aeronautics and Space Administration (NASA),It is the first time to detect a free floating black hole completely independent of the stellar companion. This "wandering black hole" 5000 light-years away is located in the spiral arm of Sagittarius in the Milky Way.[19]
Launch history
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April 24, 1990, in the United StatesKennedy Space CenterBy“Discoverer”The space shuttle successfully launched[1]The main task of the Hubble Space Telescope is to explore the deep space of the universe, solve the mystery of the origin of the universe, and understand the evolution process of the solar system, the Milky Way and other galaxies[5]。
As early as 1986, the Hubble Space Telescope was planned to be launched in October that year.But the Challenger accident brought the US space program to a standstill, and the suspension of the launch of the space shuttle forced the launch of the Hubble Space Telescope to be delayed for several years.The telescopes and all accessories must be stored in dust-free rooms by category until the launch date can be scheduled, which also makes the total cost of overruns even higher.
Finally, with the launch of the space shuttle in 1988, the telescope is scheduled to be launched in 1990.In the final preparation before launch, the mirror surface is sprayed with nitrogen to remove the dust that may accumulate, and all systems are extensively tested.Finally, on April 24, 1990, the Space Shuttle Discovery successfully put the telescope into the planned orbit on the STS-31 voyage.
From its original total budget of about $400 million to the current cost of more than $2.5 billion, the cost of Hubble is still accumulating and increasing.The US government estimates that spending will be as high as US $4.5 billion to US $6 billion, and Europe will also inject as much as 600 million euros (estimated in 1999).
On orbit operation
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Carry instrument
At launch, the instruments carried by the Hubble Space Telescope are as follows:
Wide area and planetary cameras (WF/PC)
Goddard High Resolution Spectrograph (GHRS)
High speed photometer (HSP)
Dark Celestial Camera (FOC)
Dark Object Spectrograph (FOS)
WF/PC originally planned to use high-resolution cameras for optical observation.Manufactured by NASA's Jet Propulsion Laboratory, it is equipped with a set of 48 optical filters, which can screen special wave bands for astrophysical observation.The whole instrument uses 8 CCD, and two cameras are made, each of which uses 4 CCD.The Wide Area Camera (WFC) loses its resolving power due to its wide field of vision, while the Planetary Camera (PC) images at a longer focal length than WFC, so it has a higher magnification.
GHRS is a spectrograph designed to be used in the ultraviolet band, manufactured by Goddard Space Center, which can achieve a spectral resolution of 90000, and also select suitable observation targets for FOC and FOS.Both FOC and FOS are the instruments with the highest resolution on the Hubble Space Telescope.These three instruments all abandon CCD and use digital photon counter as the detection device.FOC is manufactured by the European Space Agency and FOS is manufactured by Martin Marietta.
The last instrument is HSP designed and manufactured by the University of Wisconsin Madison, which is used to observe the changes in brightness of variable stars and other selected objects in the visible and ultraviolet light bands.Its photometer can detect 100000 times per second with an accuracy of at least 2%.
The guidance system of the Hubble Space Telescope can also be used as a scientific instrument. Its three fine guide star sensors (FGS) are mainly used to maintain the accuracy of telescope pointing during observation, but can also be used for very accurate astrometry, with the accuracy of 0.0003 arc seconds.
Maintenance
First repair/maintenance
In 1993, astronauts removed wide-angle and planetary cameras from the first Hubble maintenance mission and installed a more powerful "successor" - No. 2 wide-angle and planetary camera[6]。
Second repair/maintenance
In the early morning of February 11, 1997, seven American astronauts took off in the space shuttle Discovery to transform the Hubble Space Telescope, which had been in space for seven years.From the late night of February 13 to the early morning of February 18, astronauts replaced 11 new equipment for Hubble, including the near-infrared camera, the multi-target spectrometer and the space telescope image spectrograph, and repaired some of the insulation peeled off on the telescope[7]。
Third repair/maintenance
The third maintenance mission was still carried out by Discovery during the STS-103 voyage in December 1999.In this maintenance, all six gyroscopes were replaced, and a fine star guide sensor and calculator were also replaced. An assembled voltage/temperature improvement tool (VIK) was installed to prevent the battery from overheating, and the thermal insulation blanket was replaced[6]。
Fourth repair/maintenance
In 2001, scientists used the US space shuttle Columbia to carry out the fourth maintenance of the Hubble telescope, install mapping cameras, replace solar panels and power control devices that have been working for 11 years, and activate the dormant near-infrared camera and multi target spectrometer[8]。
Fifth repair/maintenance
In 2009, the United States used the space shuttle to maintain the Hubble telescope[9]。Astronauts installed two new sets of instruments for Hubble: the Cosmic Origin Spectrometer (COS) and the Wide Field Camera 3. They carried out on-site maintenance on the other two instruments of the telescope, the Advanced Sky Survey Camera (ACS) and the Space Telescope Imaging Spectrometer (STIS). In addition, they replaced Hubble's 18 year old batteries with new batteries,Six new gyroscopes for telescope pointing have been installed, and a new set of fine guidance system has been added to help the telescope point in the right direction[3]。
Sixth repair/maintenance
In April 2024, NASA announced that the Hubble Space Telescope had entered a safe mode and stopped scientific observation on the 23rd due to the failure of the gyroscope.The space agency is working to solve the problem, and the overall situation of the telescope remains good.[28]
Parameter characteristics
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The Hubble Telescope has a diameter of 2.4 meters and a length of about 16 meters. It has a variety of instruments for observing faint celestial bodies. It orbits the Earth about 640 kilometers above the ground and patrols the universe.Because it is located above the atmosphere, unlike ground-based telescopes, it is affected by atmospheric turbulence, greatly expanding people's understanding of the universe[10]。
Scientific research achievements
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Major achievements of the Hubble Space Telescope during the first seven years of service
1. It has enhanced human understanding of the size and age of the universe.
2. It is proved that there are supermassive black holes in the center of some cosmic galaxies and black holes may exist in the center of most galaxies.
3. In the visible spectrum range, we have conducted the most in-depth research on the universe, observed thousands of galaxies, and detected the "primitive galaxies" in the early days of the universe, making it possible for astronomers to track and study the history of the universe.
4. It clearly shows the existence environment of quasars, the brightest celestial bodies in the Milky Way.
5. The different processes of star formation are explained more clearly.
6. The composition of heavy elements in the process of star formation at the early stage of the birth of the universe has been studied. These elements are the necessary conditions for the existence of planets and life.
7. It shows the complex composition of the gas shell around the dead star.
8. The detection of many dust disks around young stars in the Orion Nebula shows that other planetary systems may form in the Milky Way where the Earth is located.
9. The once in a lifetime Huimu collision was observed in detail.
10. The Ministry of Civil Affairs has studied the climate on Mars and other solar system planets.
11. Discovery of Jupiter's moonEuropaandGanymedeThere is oxygen in the atmosphere of[7]。
The Hubble Space Telescope has discovered a hot "rugby" shaped exoplanet.The planet is torn and heated because it is too close to the star. The atmosphere is also accelerating to escape, and the whole planet is on the edge of being swallowed.The planet is too close to the star and is on the edge of being torn by tidal forces.This "death embrace" has distorted it into a football shape, and the upper atmosphere temperature is more than 2500 degrees Celsius[11]。
In January 2020, an international team of astronomers used the U.S. Hubble Space Telescope to discover the most remote and oldest galaxy cluster known so far.This triple group of galaxies is called EGS77.More importantly, the observation shows that this triple galaxy group participated in the transformation process called "re ionization" in the early universe.EGS77 was born about 680 million years after the Big Bang, when the age of the universe was less than 5% of the current 13.8 billion years.[12]
The most distant single star observed
On March 30, 2022, NASA said that the Hubble Space Telescope had discovered the most distant single star ever observed by humans through the "gravitational lens" effect.[17]
Hubble Space Telescope Captures the "Prawn Nebula" Drifting in the Far Universe
On May 30, 2022, according to foreign media reports, at present, the latest Hubble Space Telescope observation image shows local features of the Prawn Nebula. The region is colorful and dazzling, including bright glowing gas.[18]
Hubble Space Telescope Captures the "Prawn Nebula" Drifting in the Far Universe[18]
Capture new images of Phantom Galaxy
Hubble Space Telescope Captures the "Prawn Nebula" Drifting in the Far Universe
On August 30, 2022 local time, it was reported that the Hubble Telescope and the James Weber Telescope jointly developed by NASA and the European Space Agency recently captured a new image of the Mirage Galaxy, officially named M74, located 32 million light-years from the EarthPisces。[20]
In November 2022, the Hubble Space Telescope successfully captured the picture of Pismis 26 globular cluster.The cluster is located in the constellation Scorpius, near the center of the Milky Way Galaxy, 23000 light-years away from Earth.[21]
Capture three images spanning 8 days
On December 9, 2022, researchers said that,NASAThe Hubble Space Telescope successfully captured three images spanning eight days, the first of which was captured only hours after the explosion.Considering the time and distance of the explosion, this achievement deserves more attention.
The first image comes from about 6 hours after the explosion started, showing that the explosion started on a relatively small scale and was unusually hot, with a temperature of about 100000 degrees Kelvin/99725 degrees Celsius.The second image comes from about two days later, and the third image comes from about six days after the second image.In these two images, the gaseous matter ejected by the star can be seen expanding outward.In the second image, the heat of the explosion is only one fifth of that in the first image.The heat in the third image is only one tenth of that in the first image.[23]
"Water World" exoplanets
In December 2022, a group of "exoplanet hunters" announced in the journal Nature Astronomy that they had discovered two exoplanets full of water, namely Kepler-138c and Kepler-138d, using NASA's Hubble Space Telescope and the retired Spitzer Space Telescope.[24]
Discover the "runaway" black hole
On April 10, 2023, the US Fun Science Network reported that when researchers used the Hubble Space Telescope to observe the dwarf galaxy RCP 28, which is about 7.5 billion light years away from the Earth, they found a "runaway" black hole, which appears as a bright stripe.[25]
New pictures of barred spiral galaxy NGC 4535
New pictures of spiral galaxy NGC 4535
On February 19, 2024, it was reported that NASA astronomers were still observing the universe with the help of the Hubble Space Telescope. In the latest dynamic update,Shared new pictures of the barred spiral galaxy NGC 4535, 54 million light-years away from Earth.[27]
Problem maintenance
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From its original idea in 1946 until its launch, the plan to build a space telescope was constantly delayed and plagued by budget problems.After it is launched, it is immediately found that the primary mirror has spherical aberration, which seriously reduces the observation ability of the telescope.Fortunately, after the maintenance mission in 1993, the telescope recovered its planned quality and became the most important tool for astronomical research and public relations promotion.[13]
The future of Hubble depends on the success of subsequent maintenance tasks. Several gyroscopes that maintain stability have been damaged. By 2007, even the spare ones had been exhausted, and the function of another telescope used for pointing is also declining.The gyroscope must be repaired manually. On January 30, 2007, the main Advanced Sky Survey Camera (ACS) also stopped working. Before manual maintenance, only ultra ultraviolet channels can be used.On the other hand, if there is no further elevation to increase the orbital height, the resistance will force the telescope to re-enter the atmosphere in 2010.Since the tragic incident of the Space Shuttle in Columbia in 2003, the International Space Station and Hubble are not at the same height, which makes astronauts lack safe refuge in emergency situations. Therefore, NASA believes that manned space missions to repair Hubble telescopes are unreasonable dangerous missions.NASAAfter the re review, Chief Executive Mike Griffin decided to carry out the last Hubble maintenance mission in Atlanta on October 31, 2006. The mission was scheduled for September 11, 2008. Based on safety considerations, Discovery will be put on standby on LC-39B launch pad at that time to provide rescue in case of emergency.The planned maintenance will enable the Hubble Space Telescope to continue to work until 2013.If successful, the subsequent James Weber Space Telescope (JWST) should have been launched and can be connected to the mission.Weber Space Telescope is far more powerful than Hubble in many research projects, but it will only observe infrared light, so it cannot replace Hubble's function in the field of visible light and ultraviolet light in the spectrum.
Existing problems
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Lens defect
A few weeks after the launch of the telescope, the pictures sent back showed that there were serious problems in the optical system.Although the first image looks sharper than the ground-based telescope, the telescope obviously does not reach the optimal focusing state, and the best image quality obtained is far lower than the original expectation.The image of the point source is diffused into a circle with a radius of more than one arc second, instead of the standard in the design criteria: the point diffuse function image with a diameter of 0.1 arc second and concentric circles.
The analysis of the pattern defects shows that the root cause of the problem is that the shape of the main mirror is worn wrong.The mirror edge is a little flat, about 2.2 microns from the required position, but this difference causes catastrophic and serious spherical aberration.The reflected light from the mirror edge cannot be focused on the same focus as the reflected light in the center.
The effect of mirror defects is that on the core observation of scientific observation, the PSF of core aberration should be sharp enough to carry out high-resolution resolution, but it is not affected by bright celestial bodies and spectral analysis.Although, a large amount of light lost at the periphery can not converge on the focus, resulting in halo, which seriously impairs the telescope's ability to observe dark objects or high contrast images.This means that almost all research plans on cosmology cannot be implemented, because they are very weak observation objects.NASA and the Hubble Space Telescope have become the targets of many jokes and are considered to be big white elephants.
The root cause of the problem
Tracing back from the point source image, astronomers determined that the cone constant of the mirror is − 1.01324, rather than − 1.00230 as originally expected.The same values were obtained by analyzing Perkin Elmer's zero corrector (an instrument that accurately measures polished surfaces) and the interferogram image of the mirror tested on the ground.
The committee led by Aaron, the director of the Jet Propulsion Laboratory, determined how the error occurred.The Aaron Committee found that the zero corrector used by Perkin Elmer had an error in assembly, and its field lens position had deviated by 1.3 mm.
During polishing the mirror, Perkin Elmer used two other zero correctors, both of which (correctly) showed that the mirror had spherical aberration.These tests are designed to truly eliminate spherical aberration. Regardless of the guidance of quality control documents, the company believes that the accuracy of these two zero correctors is not as good as that of the main equipment, and ignores the test results.
The committee pointed out that the main cause of the failure was Perkin Elmer.Due to the frequent schedule changes and the cost overrun of telescope manufacturing, the relationship between NASA and optical companies is extremely tense.NASA found that Perkin Elmer did not think that mirror making was a key and difficult job in their business, and NASA failed to fulfill its responsibilities before polishing.While the committee painfully criticized Perkin Elmer for his improper and missing management, NASA was also criticized for failing to fulfill its quality control responsibilities and should not rely on the test results of only one instrument.
Solution
The maintenance task was originally planned in the design of the telescope, so astronomers immediately began to look for solutions that could solve the problem when the first maintenance task was scheduled in 1993.It is too expensive and time-consuming for Kodak to make a spare mirror for Hubble and replace it on the track, so it is impossible to take the telescope back to the ground for repair temporarily.On the contrary, the wrong shape of the lens has been accurately measured, so an optical system with the same spherical aberration but opposite effect can be designed to offset the error.In the first maintenance task, Hubble was equipped with a pair of glasses that can correct spherical aberration.
Due to the design of the original instrument, two sets of different calibration instruments must be used.The design of wide area and planetary cameras includes rotating lenses and light from eight independent CCD chips that directly enter the two cameras. A mirror with anti spherical aberration can completely eliminate the main deformation on their surfaces.The correction mirror was fixed in the replacement of the second generation wide area and planetary camera (due to the pressure of schedule and budget, only 4 CCD's were corrected instead of 8).However, other instruments lack any intermediate surface that can be placed, so an additional correction device is necessary.
COSTAR
The instrument designed to correct spherical aberration is called "Space Telescope Optical Axis Compensation Correction Optics" (COSTAR), which basically includes two mirrors on the optical path, one of which corrects spherical aberration, and the light is focused to the dark celestial camera, dark celestial spectrometer, and Goddard high resolution spectrograph.In order to provide the required position of COSTAR in the telescope, one of the instruments must be removed. Astronomers choose to sacrifice the high-speed photometer.
During the first three years of the Hubble mission, the telescope still carried out a lot of observations before the optical system was corrected to fit.Spectral observations were not affected by spherical aberrations, but many observations of faint objects were cancelled or delayed due to poor performance of telescopes.Despite setbacks, optimistic astronomers have made many scientific advances in the past three years by skillfully using image processing techniques, such as inversion (image overlap).
Software failure
March 7, 2021.The Hubble Space Telescope was suspended due to a software failure;On March 12, the telescope has partially resumed its work, but there are still problems that have not been eliminated.
NASA said that the Hubble Space Telescope has completed its first scientific observation since it resumed operation, and has used the Cosmic Spectrometer to map the gas flow in the core of an active galaxy.However, the No. 3 Wide Field Camera (WFC3) is still suspended. Researchers found a low voltage problem, which caused the camera to fail to start.[15]
Computer failure
On June 19, 2021, NASA said that the Hubble Space Telescope, which has been observing the universe for more than 30 years, was shut down in the past few days because a payload computer stopped working since the 13th.NASA said that the payload computer is used to control and coordinate scientific instruments and monitor them for health and safety purposes;In addition, NASA said that the Hubble telescope itself and its accompanying scientific instruments are "in good condition".NASA tried to restore the computer on Monday, but failed.Preliminary evidence shows that the root cause of the problem is the deterioration of the computer memory module, but the attempt to switch the spare memory module also failed.[16]
Value significance
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The Hubble Space Telescope was launched in 1990. For more than 20 years, it has been continuously sending beautiful cosmic images back to the Earth.(CCTV)[3]
Since the launch of the Hubble Space Telescope 27 years ago, it has made many breakthrough discoveries, constantly bringing us surprises, and we are lucky to touch the mystery billions of light years away.(China Youth Online Review)[1]
As of March 2015, the Hubble Space Telescope has been orbiting the Earth for 25 years, and the photos it captured are fundamentally changing our understanding of the universe.(Xinhuanet)[14]
As of 2009, since the launch of the U.S. Hubble Space Telescope in 1990, more than 2000 scientists from more than 20 countries have made more than 110000 astronomical observations using this "space eye", and have written 1346 papers based on the analysis of observation data.(China Network)[7]
Equipment evaluation
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The Hubble Space Telescope cost US $2.1 billion. It took more than 40 years from the initial concept, design to completion.(Popular Science China)[5]
world record
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As of April 24, 2022, it is still in operation - the mission period has reached 32 years, setting a Guinness World Record for the longest running space telescopeRecord).[26]
