Five premier multi-wavelength sky regions are selected; each has multi-wavelength data from Spitzer and other facilities, and has extensive spectroscopy of the brighter galaxies. The program, officially named "Hubble Deep Fields Initiative ", is aimed to advance the knowledge of early galaxy formation by studying high-redshift galaxies in blank fields with the help of gravitational lensing to see the "faintest galaxies in the distant universe. Anyone can apply for time on the telescope; there are no restrictions on nationality or academic affiliation, but funding for analysis is only available to US institutions.
Calls for proposals are issued roughly annually, with time allocated for a cycle lasting about one year. Proposals are divided into several categories; "general observer" proposals are the most common, covering routine observations. Snapshot observations are used to fill in gaps in the telescope schedule that cannot be filled by regular GO programs.
- The Future of Hubble;
- Team Hubble: Servicing Missions.
- A Plan to Save Hubble.
Astronomers may make "Target of Opportunity" proposals, in which observations are scheduled if a transient event covered by the proposal occurs during the scheduling cycle. Astronomers can apply to use DD time at any time of year, and it is typically awarded for study of unexpected transient phenomena such as supernovae. Other uses of DD time have included the observations that led to views of the Hubble Deep Field and Hubble Ultra Deep Field, and in the first four cycles of telescope time, observations that were carried out by amateur astronomers.
Public image processing of Hubble data is encouraged as most of the data in the archives has not been processed into color imagery. The first director of STScI, Riccardo Giacconi , announced in that he intended to devote some of his director discretionary time to allowing amateur astronomers to use the telescope.
Fact Sheet
The total time to be allocated was only a few hours per cycle but excited great interest among amateur astronomers. Proposals for amateur time were stringently reviewed by a committee of amateur astronomers, and time was awarded only to proposals that were deemed to have genuine scientific merit, did not duplicate proposals made by professionals, and required the unique capabilities of the space telescope.
Thirteen amateur astronomers were awarded time on the telescope, with observations being carried out between and A second study from another group of amateurs was also published in Icarus. These were projects that were both scientifically important and would require significant telescope time, which would be explicitly dedicated to each project. This guaranteed that these particular projects would be completed early, in case the telescope failed sooner than expected. The panels identified three such projects: Hubble has helped resolve some long-standing problems in astronomy, while also raising new questions.
Some results have required new theories to explain them. Among its primary mission targets was to measure distances to Cepheid variable stars more accurately than ever before, and thus constrain the value of the Hubble constant , the measure of the rate at which the universe is expanding, which is also related to its age. While Hubble helped to refine estimates of the age of the universe, it also cast doubt on theories about its future. Astronomers from the High-z Supernova Search Team and the Supernova Cosmology Project used ground-based telescopes and HST to observe distant supernovae and uncovered evidence that, far from decelerating under the influence of gravity , the expansion of the universe may in fact be accelerating.
Three members of these two groups have subsequently been awarded Nobel Prizes for their discovery. The high-resolution spectra and images provided by the HST have been especially well-suited to establishing the prevalence of black holes in the nuclei of nearby galaxies. While it had been hypothesized in the early s that black holes would be found at the centers of some galaxies, and astronomers in the s identified a number of good black hole candidates, work conducted with Hubble shows that black holes are probably common to the centers of all galaxies.
The legacy of the Hubble programs on black holes in galaxies is thus to demonstrate a deep connection between galaxies and their central black holes. The collision of Comet Shoemaker-Levy 9 with Jupiter in was fortuitously timed for astronomers, coming just a few months after Servicing Mission 1 had restored Hubble's optical performance. Hubble images of the planet were sharper than any taken since the passage of Voyager 2 in , and were crucial in studying the dynamics of the collision of a comet with Jupiter, an event believed to occur once every few centuries.
Hubble Space Telescope
Other discoveries made with Hubble data include proto-planetary disks proplyds in the Orion Nebula ; [] evidence for the presence of extrasolar planets around Sun-like stars; [] and the optical counterparts of the still-mysterious gamma-ray bursts. A unique window on the Universe enabled by Hubble are the Hubble Deep Field , Hubble Ultra-Deep Field , and Hubble Extreme Deep Field images, which used Hubble's unmatched sensitivity at visible wavelengths to create images of small patches of sky that are the deepest ever obtained at optical wavelengths.
The images reveal galaxies billions of light years away, and have generated a wealth of scientific papers, providing a new window on the early Universe. The Wide Field Camera 3 improved the view of these fields in the infrared and ultraviolet, supporting the discovery of some of the most distant objects yet discovered, such as MACSJD. In March , researchers announced that measurements of aurorae around Ganymede revealed that the moon has a subsurface ocean.
Using Hubble to study the motion of its aurorae, the researchers determined that a large saltwater ocean was helping to suppress the interaction between Jupiter's magnetic field and that of Ganymede. On December 11, , Hubble captured an image of the first-ever predicted reappearance of a supernova, dubbed " Refsdal ", which was calculated using different mass models of a galaxy cluster whose gravity is warping the supernova's light.
Astronomers spotted four separate images of the supernova in an arrangement known as an Einstein Cross. The detection of Refsdal's reappearance served as a unique opportunity for astronomers to test their models of how mass, especially dark matter , is distributed within this galaxy cluster. On March 3, , researchers using Hubble data announced the discovery of the farthest known galaxy to date: Many objective measures show the positive impact of Hubble data on astronomy.
Over 15, papers based on Hubble data have been published in peer-reviewed journals, [] and countless more have appeared in conference proceedings. On average, a paper based on Hubble data receives about twice as many citations as papers based on non-Hubble data. Although the HST has clearly helped astronomical research, its financial cost has been large. Deciding between building ground- versus space-based telescopes is complex. Even before Hubble was launched, specialized ground-based techniques such as aperture masking interferometry had obtained higher-resolution optical and infrared images than Hubble would achieve, though restricted to targets about 10 8 times brighter than the faintest targets observed by Hubble.
The usefulness of adaptive optics versus HST observations depends strongly on the particular details of the research questions being asked. In the visible bands, adaptive optics can only correct a relatively small field of view, whereas HST can conduct high-resolution optical imaging over a wide field. Only a small fraction of astronomical objects are accessible to high-resolution ground-based imaging; in contrast Hubble can perform high-resolution observations of any part of the night sky, and on objects that are extremely faint. In addition to its scientific results, Hubble has also made significant contributions to aerospace engineering , in particular the performance of systems in low Earth orbit.
These insights result from Hubble's long lifetime on orbit, extensive instrumentation, and return of assemblies to the Earth where they can be studied in detail. In particular, Hubble has contributed to studies of the behavior of graphite composite structures in vacuum, optical contamination from residual gas and human servicing, radiation damage to electronics and sensors, and the long term behavior of multi-layer insulation.
Gyros are now assembled using pressurized nitrogen. Hubble data was initially stored on the spacecraft.
HubbleSite - Team Hubble - Servicing Missions
When launched, the storage facilities were old-fashioned reel-to-reel tape recorders , but these were replaced by solid state data storage facilities during servicing missions 2 and 3A. All images from Hubble are monochromatic grayscale , taken through a variety of filters, each passing specific wavelengths of light, and incorporated in each camera.
Color images are created by combining separate monochrome images taken through different filters. This process can also create false-color versions of images including infrared and ultraviolet channels, where infrared is typically rendered as a deep red and ultraviolet is rendered as a deep blue. Observations made on Director's Discretionary Time are exempt from the proprietary period, and are released to the public immediately. Calibration data such as flat fields and dark frames are also publicly available straight away.
All data in the archive is in the FITS format, which is suitable for astronomical analysis but not for public use. Astronomical data taken with CCDs must undergo several calibration steps before they are suitable for astronomical analysis. STScI has developed sophisticated software that automatically calibrates data when they are requested from the archive using the best calibration files available. This 'on-the-fly' processing means that large data requests can take a day or more to be processed and returned. The process by which data is calibrated automatically is known as 'pipeline reduction', and is increasingly common at major observatories.
Astronomers may if they wish retrieve the calibration files themselves and run the pipeline reduction software locally. This may be desirable when calibration files other than those selected automatically need to be used. Hubble data can be analyzed using many different packages. The software runs as a module of IRAF , a popular astronomical data reduction program. It has always been important for the Space Telescope to capture the public's imagination, given the considerable contribution of taxpayers to its construction and operational costs.
Several initiatives have helped to keep the public informed about Hubble activities. The Hubble Heritage Project , operating out of the STScI, provides the public with high-quality images of the most interesting and striking objects observed. The Heritage team is composed of amateur and professional astronomers, as well as people with backgrounds outside astronomy, and emphasizes the aesthetic nature of Hubble images.
The Heritage Project is granted a small amount of time to observe objects which, for scientific reasons, may not have images taken at enough wavelengths to construct a full-color image. The work is centered on the production of news and photo releases that highlight interesting Hubble results and images. ESA produces educational material, including a videocast series called Hubblecast designed to share world-class scientific news with the public.
The Hubble Space Telescope celebrated its 20th anniversary in space on April 24, Past servicing missions have exchanged old instruments for new ones, both avoiding failure and making possible new types of science. Without servicing missions, all of the instruments will eventually fail. The electronics had originally been fully redundant, but the first set of electronics failed in May Similarly, the Advanced Camera for Surveys ACS main camera primary electronics failed in June , and the power supply for the backup electronics failed on January 27, A new power supply for the wide angle channel was added during SM 4, but quick tests revealed this did not help the high resolution channel.
HST uses gyroscopes to detect and measure any rotations so it can stabilize itself in orbit and point accurately and steadily at astronomical targets. The gyroscopes are part of the Pointing Control System which has five types of sensor: Three gyroscopes are normally required for operation; observations are still possible with two or one, but the area of sky that can be viewed would be somewhat restricted, and observations requiring very accurate pointing are more difficult.
After the Columbia disaster in , it was unclear whether another servicing mission would be possible, and gyro life became a concern again, so engineers developed new software for two-gyro and one-gyro modes to maximize the potential lifetime. The development was successful, and in , it was decided to switch to two-gyroscope mode for regular telescope operations as a means of extending the lifetime of the mission.
The switch to this mode was made in August , leaving Hubble with two gyroscopes in use, two on backup, and two inoperable. By the time of the final repair mission in May , during which all six gyros were replaced with two new pairs and one refurbished pair , only three gyros were still working. Engineers determined that the gyro failures were caused by corrosion of electric wires powering the motor that was initiated by oxygen-pressurized air used to deliver the thick suspending fluid. Of the six gyroscopes replaced in , three were of the old design susceptible for flex-lead failure, and three were of the new design with a longer expected lifetime.
The first of the old-style gyros failed in March , and the second of the old-style gyros failed in April On October 5, , the last of the old-style gyros failed, and one of the new-style gyros was powered-up from standby state. However, that reserve gyro did not immediately perform within operational limits, and so the observatory was placed into "safe" mode while scientists attempted to fix the problem.
Additional tests to be performed to ensure Hubble can return to science operations". The solution that restored the backup new-style gyro to operational range was widely reported as "turning it off and on again". The failure was attributed to an inconsistency in the fluid surrounding the float within the gyroscope e.
On October 18, the Hubble Operations Team directed the spacecraft into a series of maneuvers - moving the spacecraft in opposite directions - in order to mitigate the inconsistency. Only after the maneuvers, and a subsequent set of maneuvers on October 19, did the gyroscope truly operate within its normal range. Hubble orbits the Earth in the extremely tenuous upper atmosphere , and over time its orbit decays due to drag.
If it is not re-boosted, it will re-enter the Earth's atmosphere within some decades, with the exact date depending on how active the Sun is and its impact on the upper atmosphere. If Hubble were to descend in a completely uncontrolled re-entry, parts of the main mirror and its support structure would probably survive, leaving the potential for damage or even human fatalities.
NASA's original plan for safely de-orbiting Hubble was to retrieve it using a space shuttle. Hubble would then have most likely been displayed in the Smithsonian Institution. This is no longer possible since the space shuttle fleet has been retired , and would have been unlikely in any case due to the cost of the mission and risk to the crew. Instead, NASA considered adding an external propulsion module to allow controlled re-entry.
As of [update] , the Trump Administration is considering a proposal by the Sierra Nevada Corporation to use a manned version of its Dream Chaser spacecraft to service Hubble some time in the s both as a continuation of its scientific capabilities and as insurance against any malfunctions in the to-be-launched James Webb Space Telescope. There is no direct replacement to Hubble as an ultraviolet and visible light space telescope, because near-term space telescopes do not duplicate Hubble's wavelength coverage near-ultraviolet to near-infrared wavelengths , instead concentrating on the farther infrared bands.
These bands are preferred for studying high redshift and low-temperature objects, objects generally older and farther away in the universe. These wavelengths are also difficult or impossible to study from the ground, justifying the expense of a space-based telescope. Large ground-based telescopes can image some of the same wavelengths as Hubble, sometimes challenge HST in terms of resolution by using adaptive optics AO , have much larger light-gathering power, and can be upgraded more easily, but cannot yet match Hubble's excellent resolution over a wide field of view with the very dark background of space.
It is not engineered to be fully serviceable such as replaceable instruments , but the design includes a docking ring to enable visits from other spacecraft. It is expected to detect stars in the early Universe approximately million years older than stars HST now detects. Like JWST, Herschel was not designed to be serviced after launch, and had a mirror substantially larger than Hubble's, but observed only in the far infrared and submillimeter. It needed helium coolant, of which it ran out on April 29, Further concepts for advanced 21st-century space telescopes include the Advanced Technology Large-Aperture Space Telescope , [] a conceptualized 8 to This effort is being planned for the — time frame.
Existing ground-based telescopes, and various proposed Extremely Large Telescopes , can exceed the HST in terms of sheer light-gathering power and diffraction limit due to larger mirrors, but other factors affect telescopes. In some cases, they may be able to match or beat Hubble in resolution by using adaptive optics AO. However, AO on large ground-based reflectors will not make Hubble and other space telescopes obsolete.
Op-ed | A Not-so-final Servicing Mission
Furthermore, space telescopes can study the universe across the entire electromagnetic spectrum, most of which is blocked by Earth's atmosphere. Finally, the background sky is darker in space than on the ground, because air absorbs solar energy during the day and then releases it at night, producing a faint—but nevertheless discernible— airglow that washes out low-contrast astronomical objects. From Wikipedia, the free encyclopedia.
For other uses, see Hubble disambiguation. Space Telescope Science Institute. Hubble's low orbit means many targets are visible for somewhat less than half of an orbit's elapsed time, since they are blocked from view by the Earth for one-half of each orbit. Animation of Hubble's orbit from October 31, , to December 25, Earth is not shown. List of Hubble anniversary images. James Webb Space Telescope. Astronomy portal Spaceflight portal. Archived from the original on July 6, Archived from the original on May 7, Retrieved May 7, Retrieved June 3, Retrieved August 16, Retrieved April 26, Retrieved March 3, Retrieved June 28, Archived from the original on March 27, NASA originally discussed plans to return Hubble to Earth at the end of its mission, but with the shuttle fleet retiring that's not in the cards now.
Lead STS spacewalker John Grunsfeld has said even if NASA wanted to, Hubble may now be too big and heavy with all the added hardware over the last 19 years to fit in a shuttle payload bay. During the STS mission, spacewalkers will attach a soft docking mechanism, a docking port for a future robotic spacecraft that - at the end of Hubble's mission - could latch on and then steer the school bus-sized space telescope into a controlled re-entry. A sort of space cremation, most likely over the Pacific Ocean.
Grunsfeld said the jury is still out on this. NASA could also attach a motor and boost it into a graveyard, or museum orbit. In terms of the decommissioning, isn't it true that the robotic vehicle that would use the soft-docking mechanism for Hubble is not even built yet?
Right now, NASA's plan is to use a generic soft-docking mechanism, one it has developed for spacecraft like Orion and others at the International Space Station. The robotic craft envisioned to steer Hubble down to its death or a graveyard orbit is not yet built. How much will the mission to Hubble cost?
- Hubble Space Telescope: NASA's Plans for a Servicing Mission;
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- NASA - Hubble Space Telescope Servicing Mission 4;
The cost has swelled due to the last few years of delays. Can NASA save money and risk by building a new space telescope to replace Hubble instead of flying the servicing mission? Weiler has said that while the cost of the mission is one that can be criticized, even attempting to build a new space telescope would face the same scrutiny later on because cost overages would most assuredly follow then too.
However, a future space telescope - like a daughter of Hubble - would cost much more, be larger and require a new launch vehicle like NASA? She graduated from Georgia Tech with a B. Hubble would be able to see 90 times more objects than it did at launch in April This instrument will replace Hubble? This instrument uses the ultraviolet range to find out the temperature, density, chemical composition and velocity of intergalactic gas and galaxies, with ten times the sensitivity of current Hubble instruments.
This device will replace Hubble? The corrective optics are no longer required because all of Hubble? Attaching the Soft Capture and Rendezvous System: This docking port will allow a future spacecraft, most likely robotic, to latch onto Hubble in order to guide it to a fiery demise in Earth? The gyroscopes help keep Hubble pointed precisely at distant stars and galaxies for hours at a time. Hubble can technically limp by on two or even one gyroscope, but the fresh exchange ensures that the science keeps flowing.
Replace one of three Fine Guidance Sensors: Hubble has three Fine Guidance Sensors used to keep the telescope stead for long-duration observations. They are also used for astrometry, which studies the precise position and motion of stars. Replacing six Nickel Hydrogen Batteries: The suitcase -sized batteries get swapped out for the first time in 16 years, giving Hubble an extra lease on life for the next 5 to 10 years. The batteries keep Hubble humming during the night portion of its orbit.
The multilayer insulation on Hubble has become torn and broken by the harsh environment of space. The new thermal blankets protect the damaged insulation and helps maintain a steady temperature for Hubble. A two-sided instrument that uniquely scans across all light wavelengths of objects such as planets, comets, stars and galaxies. Spacewalkers will replace a failed power converter to restore one side of the damaged device.
One of three optical sensors that help Hubble lock onto targets with a system of mirrors and lenses. The old FGS returns home after being removed from Hubble during an earlier servicing mission. On November 13, , the Hubble Space Telescope was placed into "safe mode" after the failure of a fourth gyroscope. In safe mode Hubble could not observe targets, but its safety was preserved. This protective mode allows ground control of the telescope, but with only two gyros working, Hubble cannot be aimed with the precision necessary for scientific observations of the sky.
Controllers closed the aperture door to protect the optics and aligned the spacecraft to ensure that Hubble's solar panels would receive adequate power from the sun. There is no question that Hubble's "first generation" cameras gave us remarkable views of very distant galaxies.
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However the light from the most distant galaxies is shifted to infrared wavelengths by the expanding universe. To see these galaxies, Hubble needed to be fitted with an instrument that could observe infrared light. During the day Second Servicing Mission STS in February , the seven astronauts aboard the space shuttle Discovery installed two technologically advanced instruments. The second instrument — the versatile Space Telescope Imaging Spectrograph STIS — would be used to take detailed pictures of celestial objects and to hunt for black holes.
Both instruments had optics that corrected for the flawed primary mirror. In addition, they featured technology that wasn't available when scientists designed and built the original Hubble instruments in the late s — and opened up a broader viewing window for Hubble. The mission's most important objective was to install two devices to fix Hubble's vision problem.
Because Hubble's primary mirror was incorrectly shaped, the telescope could not focus all the light from an object to a single sharp point. Instead, it saw a fuzzy halo around objects it observed. Once astronauts from the space shuttle Endeavour caught up with the orbiting telescope, they hauled it into the shuttle's cargo bay and spent five days tuning it up.
This successful mission not only improved Hubble's vision — which led to a string of remarkable discoveries in a very short time — but it also validated the effectiveness of on-orbit servicing. Servicing Missions On this page: Shuttle flights enable on-orbit repairs and instrument upgrades. HubbleSite works better when you install the latest Flash Player for your browser. President Obama Calls the Crew. Listen in on the conversation. SM4 Step-by-step Follow the tasks of Servicing Mission 4, learning the background and detail of each step. Advanced Camera for Surveys — this technologically advanced science instrument produces large, detailed images of our universe.
Enlarge image NASA had originally planned 4 days of spacewalks, but condensed the mission to 3 days because of a weather-delayed launch. The Hubble Telescope begins its separation from Discovery following its release. Enlarge image Astronauts use the remote manipulator system to perform spacewalk duties. Enlarge image Hubble sees galaxy more clearly after servicing.