The primary purpose of the James Webb Space Telescope (JWST) is infrared astronomy. With the most powerful infrared resolution and sensitivity ever sent into space, the JWST can view objects that are too old, distant, or faint for the telescope. For example, it is expected to enable a wide range of astronomical and cosmological investigations, such as observations of early galaxies and thorough atmospheric characterization of exoplanets that may be habitable. After a December 2021 launch from Kourou, French Guiana, on an ESA Ariane 5 rocket, JWST entered orbit in January 2022 and is currently conducting instrument modes check-out. Upon completion in July 2022, JWST is planned to replace the Hubble as NASA's flagship astrophysics mission. Science photos will be released on July 12, 2022, at 10:30 EDT/USA for the first official NASA event.
JWST was developed by NASA, ESA, and the Canadian Space Agency in tandem (CSA). In Maryland, the Goddard Space Flight Center (GSFC), the Space Telescope Science Institute (STScI), and the prime contractor, Northrop Grumman, were all involved in creating JWST. The administrator of NASA from 1961 to 1968, James E. Webb, inspired the telescope's name.
For comparison, Hubble's primary mirror has a diameter of 2.4 meters (7.5 feet). JWST's primary mirror comprises 18 hexagonal mirror segments of gold-plated beryllium (7.9 ft). Webb's light-gathering surface will be around 25 square meters larger than Hubble's, putting it about six times as powerful. JWST will view in a lower frequency range, from long-wavelength visible light (red) to mid-infrared (0.6–28.3 m), unlike Hubble, which observes in the near ultraviolet, visible, and near-infrared (0.1–1.7 m) spectra. For infrared spectroscopy, the telescope must be maintained extremely cold, below 50 K (-223°C; -370°F), to avoid interference from heat energy. Around 1.5 million kilometers (930,000 miles) from Earth, it is placed in a solar orbit around the Sun-Earth L2 Lagrange point, where it is shielded from the Sun, Earth, and Moon by its five-layer kite-shaped sunshield.
Initially scheduled for 2007 with a budget of $500 million, development began in 1996. One significant redesign in 2005, a shredded sunshield during practice deployment, recommendations from an independent board of review, and threats from the United States contributed to delays and cost overruns. In addition to the COVID-19 epidemic and telescope malfunctions, Congress has decided to scrap the project. The media, scientists, and engineers noted the launch's enormous stakes and the telescope's complexity. In late 2016, the project was completed, followed by years of testing before it was ready to go into production. An estimated $9.7 billion in total costs have been calculated for the project.
The James Webb Space Telescope weighs almost half as much as the Hubble Space Telescope. The primary mirror of the JWST measures 6.5 meters (21 feet) in diameter and comprises 18 individual hexagonal mirrors coated in gold. Of the 26.3 m2 polished surface area, 9.7 square feet of auxiliary support struts obscure 9.7 square feet at the total collecting area of 25.4 m2 (273 sq ft). The Hubble Space Telescope's 2.4-meter (7.9-foot) diameter mirror's collecting area of 4.0 m2 is dwarfed by this (43 sq ft). A gold coating on the mirror provides infrared reflectivity and endurance.
Near-infrared and mid-infrared astronomy are the primary goals of the JWST. However, depending on the equipment, it can also observe orange and red visible light and the mid-infrared area. Up to 100 times fainter than Hubble, it can identify objects from a considerably earlier time, as far back as z20 (about 180 million years cosmic time after the Big Bang). Comparatively, the earliest stars are thought to have been born in the time 100 million years after the Big Bang, with a redshift of z20, while the first galaxies may have emerged at z15 (about 270 million years cosmic time). Hubble can only see as far back as z11.1 in the early stages of reionization (galaxy GN-z11, 400 million years cosmic time).
The near-to-mid-infrared wavelengths are chosen for three main reasons:
Earth's atmosphere is opaque in many infrared wavelengths for telescopes located on the ground. Even in areas where the atmosphere is clear, many of the target chemical constituents, such as water, carbon dioxide, and methane, are present in the Earth's atmosphere, making analysis extremely difficult. There are currently no space telescopes capable of studying the infrared bands since their mirrors do not get cool enough (the Hubble mirror is maintained at roughly 15°C (288 K); 59°F).
Even in our own Solar System, JWST can see objects that appear to move at less than 0.030 arc seconds per second. Beyond the Earth's orbit, this includes all of the planets and their satellites, comets, asteroids, and "nearly all" of the Kuiper Belt objects discovered. For example, observations of supernovae and gamma-ray bursts can be made within 48 hours of deciding.
There's an L2 Lagrange point around 1,500,000 kilometers (930,000 miles) outside Earth's orbit around the Sun, where the JWST flies. During its orbital transition, it moves between a distance of around 160,000 kilometers (160,000 miles) and 832,000 kilometers (517,000 miles) from L2, keeping it out of the shadows of the Earth and the Moon. As a point of reference, Hubble travels 550 kilometers (340 miles) above the surface of the Earth, whereas the Moon is around 400,000 kilometers (250,000 kilometers) away from the planet. The telescope can keep its unique sunshield and equipment bus-oriented toward the Sun, Earth, and Moon while remaining at a relatively constant distance from the Sun-Earth L2 point. Because of its wide shadow-avoiding orbit, the telescope can block heat and light from all three bodies simultaneously and avoid even the slightest temperature changes caused by Earth's and the Moon's shadows, all while continuing to receive power from the Sun and communicate with Earth on its sun-facing side. This configuration maintains the spacecraft's temperature at or below 50 K (-223 °C; -370 °F), required for feeble infrared measurements.
JWST must be kept at or below 50 K (-223.2 °C; -369.7 °F) to conduct infrared observations; otherwise, the telescope's infrared radiation would overwhelm its equipment. Due to its proximity to Sun-Earth L2, it can simultaneously keep all three celestial bodies on one side of the spacecraft, thanks to a massive sunshield that blocks light and heat. Maintaining a stable environment for the sunshield and solar arrays avoids Earth's and Moon's shadows. The shielding keeps the structures on the dark side at a constant temperature, ensuring that the major mirror segments are perfectly aligned in space.
Each layer of the sunshield is made of an ultra-thin poylmer called Kapton E, a commercially available polyimide film from DuPont, which is coated on both sides with aluminum, and the Sun-facing side of the two hottest layers has a layer of doped silicon to reflect the Sun's heat into space. Delays in the project were exacerbated by accidental tears in the sensitive film structure discovered during testing in 2018.
Folded twelve times, it would fit inside the Ariane 5 rocket's payload fairing, which is 4.57 meters (15.0 feet) by 5.31 meters (16.19 feet) in length and has a diameter of 15.0 meters. The shield was designed to be 14.162 m x 21.197 m (46.46 ft x 69.54 ft) in size when completely deployed. The sunshield was built by hand at ManTech (NeXolve) in Huntsville, Alabama, before being tested at Northrop Grumman in Redondo Beach, California.
When the sunshield is in place, the field of view for JWST is limited. Forty percent of the sky is visible from one location, whereas the telescope can see all of it in six months, the time it takes for one-half of its orbit to complete.
JWST's primary mirror has a collecting surface of 25.4 m2 and is 6.5 m (21 ft) in diameter (273 sq ft). It would have been too big for current launch vehicles as a single enormous mirror. As a result, the telescope's mirror comprises 18 hexagonal pieces that unfold after it is launched. Micromotors are employed to precisely position the mirror segments based on image plane wavefront detection through phase retrieval. After this initial setup, they require occasional updates every few days to maintain their best concentration. Instead of employing a mirror segment that must be constantly adjusted to compensate for gravity and wind loads, terrestrial telescopes such as the Keck series use active optics.
Small actuators (aka actuator motors) will be used to position and modify the optic components of Webb's telescope, given there are few environmental disturbances in space. With 126 primary and six secondary mirror actuators, there are 132 actuators in the system. Each primary mirror segment is controlled by six positional actuators with an additional ROC (radius of curvature) actuator at the center to regulate curvature. The actuators can place the mirror with a precision of 10 nanometers.
Ball Aerospace & Technologies has designed and manufactured actuators vital to the telescope's mirror alignment. One stepper motor powers all 132 actuators, allowing fine and coarse adjustments. There is a coarse adjustment step size of 7 and 58 nanometers for bigger changes with the actuators.
Using curved secondary and tertiary mirrors, the optical design of JWST's three-mirror anastigmat delivers images free of optical aberrations over a large field. This mirror is 0.74 m (2.4 feet) in diameter and is used for secondary reflection. Additional picture stabilization can be provided via a fine steering mirror that adjusts its location frequently. To save weight, the rear of the major mirror pieces is hollowed out in a honeycomb design.
An optical subcontractor for the JWST project directed by Northrop Grumman Aerospace Systems under a contract from NASA's Goddard Space Flight Center in Greenbelt, Maryland, is Ball Aerospace & Technologies (BAT). Beryllium segment blanks were produced by numerous businesses, including Axsys, Brush Wellman, and Tinsley Laboratories, and the mirrors were built and polished by Ball Aerospace & Technologies.
ISIM is a structure that provides the Webb telescope with power, cooling, and structural stability. Graphite-epoxy composite has been bonded to the telescope's lower construction. Scientific instruments and a guide camera are all housed in the ISIM.
An infrared camera called NIRCam (Near Infrared Camera) has a spectral range from the edge of visible light (0.6 nm) to the near-infrared (5 nm). There are ten 4-megapixel sensors in all. For wavefront sensing and control activities, NIRCam will also serve as the observatory's wavefront sensor, which is needed to align and focus the primary mirror segments. NIRCam was created by a team directed by the University of Arizona, with Marcia J. Rieke as the lead investigator. Palo Alto, California-based Lockheed Martin is the industrial partner.
All spectrum wavelengths will be covered by NIRspect (Near-Infrared Spectrograph). In Noordwijk, Netherlands, it was built by the European Space Agency (ESTEC). NIRSpec project scientist Pierre Ferruit (École normale supérieure de Lyon) is part of the development team that comprises individuals from Airbus Defense and Space, Ottobrunn and Friedrichshafen, Germany, and the Goddard Space Flight Center. The NIRSpec design has three modes of observation: a low-resolution prism mode, a multi-object R1000 mode, and long-slit spectroscopy R2700 integral field unit mode. Preselected dispersive elements (prisms or gratings) can be selected using a mechanism known as the Grating Wheel Assembly. ISOPHOT wheel mechanisms used by the Infrared Space Observatory form the basis for both systems. The multi-object mode uses a micro-shutter mechanism to observe hundreds of unique objects from NIRSpec's perspective simultaneously. A total of eight megapixels are housed in two sensors. Carl Zeiss Optronics GmbH (now Hensoldt) of Oberkochen, Germany, designed, assembled, and tested the mechanisms and their optical elements under contract from Astrium.
The mid-to-long-infrared wavelength range (5–27 m) will be measured by MIRI (Mid-InfraRed Instrument). Both an imaging spectrometer and a mid-infrared camera are included.
Rieke (University of Arizona) and Wright (UK Astronomy Technology Centre, Edinburgh, Scotland, part of the Science and Technology Facilities Council (STFC)) are leading a coalition of European countries in the development of MIRI. A similar wheel mechanism to NIRSpec is used in MIRI, which was also created by Carl Zeiss Optronics GmbH (now Hensoldt) on contract from the Max Planck Institute for Astronomy in Heidelberg, Germany. By mid-2012, Goddard Space Flight Center had received MIRI's finished Optical Bench Assembly for integration into the ISIM. To keep the temperature of the MIRI from rising above 6 K (-267 °C; -449 °F), the environmental shield is equipped with a helium gas mechanical cooler.
Canadian Space Agency-led FGS/NIRISS (Fine Guidance Sensor and Near-Integral Imager and Slitless Spectrograph) is utilized during science observations to stabilize the telescope's field of view.
FGS measurements control both the overall orientation of the spaceship and the fine steering mirror. Research led by René Doyon of the University of Montréal with the help of a Near-Infrared Imager and Slitless Spectrograph (NIRISS) module developed by the Canadian Space Agency will be carried out in the wavelength range of 0.8 to 5 micrometers. Even though they are physically positioned next to each other, NIRISS and the FGS are referred to as a single unit because they are both parts of the astronomical observatory's support infrastructure. NIRCam and MIRI use coronagraphs that filter out starlight to observe faint objects like extrasolar planets and disks that orbit nearby stars.
Teledyne Imaging Sensors provide the infrared detectors for the NIRCam and NIRSpec, FGS, and NIRISS modules (formerly Rockwell Scientific Company). Sending data between science instruments and data-handling equipment on the James Webb Space Telescope's Integrated Science Instrument Module is done using SpaceWire.
The James Webb Space Telescope's principal support component is the spacecraft bus, which houses several computing, communication, electric power, propulsion, and structural components. It's part of the space telescope's spacecraft and the sunshield. Other significant components of JWST are the Optical Telescope Element and the Integrated Science Instrument Module (OTE). The MIRI cryocooler and the ISIM Command and Data Handling unit are in the spacecraft bus. The Deployable Tower Assembly, which also links to the sunshield, connects the spacecraft bus to the Optical Telescope Element. Sun-facing "warm" side of the sunshield is where the spacecraft bus runs at a temperature of 27 °C (80 °F).
The structure of the spacecraft bus has a mass of 350 kg (770 lb) and is required to sustain the 13,700 lb space telescope. Graphite composite is the primary component. Assembling and integrating the telescope was completed in California in 2015 and will be launched in 2021. Using a one-arcsecond pointing precision, the spacecraft bus can isolate vibrations down to two milliarcseconds from the telescope.
Using the central processor and software, the processor and software route data from and to instruments, the solid-state memory core, and the radio system that can transmit data back to Earth and receive commands. Additionally, the computer is responsible for directing the spacecraft's trajectory, taking in data from the gyroscopes and the star tracker, and issuing directions to the thrusters.
On the journey to L2 and in the halo orbit, Webb carries two pairs of rocket engines (one for redundancy) for course corrections and station holding. Attitude control, or making sure the spaceship is pointed in the right direction, is accomplished with eight smaller thrusters. Hydrazine (159 liters or 42 gallons at launch) and dinitrogen tetroxide (DTO) are used as oxidizers in the engines (79.5 liters or 21.0 US gallons at launch).
This mission is not designed to be supported in orbit. When JWST was first developed, NASA's Associate Administrator Thomas Zurbuchen said that despite best efforts, a distant uncrewed mission was deemed impossible because of the existing state of technology. Officials at NASA referred to the possibility of a JWST servicing mission, but no plans were made public. NASA claimed they had made only a little room for any future servicing missions that may be necessary. Refillable fuel tanks, heat shields, and attachment points were provided, as were accurate guidance markers in the form of crosses on JWST's surface for remote repair missions.
Infrared space telescopes have been sought after for decades. Space Infrared Telescope Facility was proposed in the United States during the Space Shuttle's development, and infrared astronomy potential was recognized then. The atmosphere does not absorb infrared light as it is with ground-based telescopes. Astronomers now have access to a "new sky" thanks to satellite observatories in orbit.
"Detectors working at all wavelengths from 5 m to 1000 m can achieve great radiometric sensitivity since the scant atmosphere above the 400 km nominal flight altitude has no appreciable absorption." – S. A collaboration between G. Witold Autio's work was published in 1978.
On the other hand, infrared telescopes have a drawback: they must be kept extremely cold, and the longer the infrared wavelength, the colder they must be. It would be impossible to detect anything if the heat from the device itself was not overwhelming the sensors. This problem can be solved with proper spacecraft design, such as housing the telescope within a dewar filled with liquid helium. Consequently, infrared telescopes can only operate for a few months or years at most due to their coolant's short lifespan.
Near-infrared observations can sometimes be made without a coolant supply because of clever spacecraft design, such as the Spitzer Space Telescope and Wide-field Infrared Survey Explorer missions that ran for lengthy periods. Cryocoolers, like the one used by Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS), was first used to keep the instrument cool but eventually drained the sensor's nitrogen supply. Cryocoolers are used in the mid-infrared instrument of the James Webb Space Telescope to keep the telescope cool without a dewar.
Hubble's delays and costs can be compared to JWST's delays and expenses. To put that into perspective, Hubble's development cost was initially projected to be $300 million. Still, by the time it was launched into orbit four years later, that figure had risen to roughly $1 billion in constant currency in 2006. At least US$9 billion was spent on new instruments and servicing missions by 2006.
There have been several other NASA observatories proposed around the same time. Still, most have been canceled or delayed, including Terrestrial Planet Finder (2011), Space Interferometry Mission (2010), the International X-ray Observatory (2011), and MAXIM (Microarcsecond X-ray Imaging Mission), SAFIR (Submillimeter Probe of the Evolution of Cosmic Structure).
A Hubble successor was first mooted in the 1980s, but it wasn't until the early 1990s that actual planning got underway. As early as 1989 and 1994, the Hi-Z telescope design was developed: a 4 m (13 ft) aperture infrared telescope that would orbit the Earth at 3 Astronomical units (AU). Light noise from dust in the zodiac may have been minimized in this faraway orbit. NEXUS precursor telescope mission was another early idea.
The starting years of the Hubble Space Telescope were critical in the James Webb Space Telescope (JWST) development. HST's primary mirror had a spherical aberration. Therefore NASA prepared STS-61, the Shuttle mission that would carry an HST camera replacement and an imaging spectrograph upgrade to correct it. For all its excitement, NASA stressed that the unprecedented advancement in functioning in space posed a significant risk and its successful completion was not a foregone conclusion.
A committee called "HST & Beyond Committee" was established in 1995 to assess the success of HST repair efforts and to brainstorm possible future space telescope designs in the event of a failure of the repair mission. Space Shuttle Servicing Mission 1 of the HST in December 1993 was a great success and received an unprecedented public response to HST's breathtaking photographs.
An infrared-sensitive telescope with a larger, colder, and a more expansive field of view was proposed for future missions in 1996, inspired by the success of the Hubble Space Telescope (HST). The HST could not accomplish this crucial scientific objective because the telescope's infrared emission blinds it. As a result of HST & Beyond's recommendations for a large, cold space telescope (with a cooling temperature well below absolute zero), NASA has begun the design process for the future James Webb Space Telescope (JWST). NASA has also agreed to extend the HST mission until 2005 and develop technologies to find planets orbiting other stars.
It has been a tradition for many decades now to bring together astronomers from around the United States to brainstorm about the next decade's research priorities and come up with fresh ideas for new astronomical devices since the 1960s. NASA has been a staunch supporter of the 'Decadal Surveys of Astronomy and Astrophysics and has had great success in creating programs and tools to carry out the recommendations of the Survey. The astronomy community considered the 2000 Decadal Survey vital, despite NASA's commencing work on a successor to the HST receiving great support and excitement in the mid-1990s.
To prepare for the Survey, NASA worked on the scientific program for the "Next Generation Space Telescope," as well as on essential technology. When "Origins" by HST & Beyond matured, the primary goals of researching the creation of galaxies in the early cosmos and hunting for planets near other stars came together.
NASA formed the 'Origins Subcommittee' in the late 1990s to oversee this work and the 'Beyond Einstein Subcommittee' to oversee missions where the cosmos serves as a laboratory for fundamental astrophysics, such as black holes and supernovae. NASA According to the 2000 Decadal Survey of Astronomy & Astrophysics, the NGST achieved the highest grade, allowing the project to proceed with the full support of the scientific community.
For the next significant paradigm change in astronomy, NASA administrator Dan Goldin coined the mantra "faster, better, cheaper" and chose to shatter the barrier of a single mirror as the solution. From "remove moving parts" to "learn how to live with moving parts," this necessitated shifting the focus (i.e., segmented optics). Although silicon carbide with a thin coating of glass on top was initially considered a possible solution to the problem of mass density, beryllium was ultimately chosen.
An 8-meter (26-foot) aperture for flight to L2 was developed in the mid-1990s as part of the "faster, better, cheaper" period. The NGST design is anticipated to cost US$500 million. For preliminary concept studies in 1999, NASA teamed up with Lockheed Martin and TRW from the Goddard Space Flight Center, Ball Aerospace & Technologies, and TRW to undertake technical requirements and cost assessments of the three concepts. The launch date was set for 2007 but was repeatedly delayed (see table further down).
James E. Webb, NASA's second administrator (1961–1968), inspired the project's renaming in 2002. Webb was in charge of NASA in the Apollo era and established scientific research as the agency's primary mission.
TRW was granted the US$824.8 million prime contract for JWST in 2003 by NASA. The plan proposed a primary mirror with a de-scoped height of 6.1 meters (20 feet) and a launch in 2010. That year, Northrop Grumman purchased TRW in a hostile bid and renamed the company to become Northrop Grumman Space Technology.
As of 2004, the European Space Agency (ESA) and Canada's Space Agency (CSA) have formally joined the JWST project, which NASA leads.
NASA's Goddard Space Flight Center in Greenbelt, Maryland, was in charge of the project's development under the direction of project scientist John C. Mather. In addition to the satellite bus, sunshield, Deployable Tower Assembly, and Mid Boom Assembly (MBA), Northrop Grumman Aerospace Systems was responsible for developing and building the spacecraft element that includes both the OTE and the Integrated Sci-Tech System. Ball Aerospace & Technologies was subcontracted to develop and build the OTE and the Integrated Sci-Tech System (ISIM).
A re-evaluation of the budget in August of that year was necessitated by an increase in costs discovered in spring 2005. A nearly 2 year launch delay and the abolition of system-level testing for observatory modes at wavelengths lower than 1.7 m were the key technical implications of the re-planning. The observatory's other significant characteristics remained untouched. A project review was carried out in April 2006 after the re-planning was completed.
The project's total life-cycle cost was projected at 4.5 billion dollars in the 2005 re-plan. It cost about US$3.5 billion to design, develop, launch, and commission the system and about US$1 billion to operate it for ten years. In 2004, the European Space Agency (ESA) agreed to contribute around €300 million, which included the launch. On July 1, 2007, Canada's Space Agency donated $39 million Canadian, and in 2012, it contributed pointing and atmospheric monitoring equipment for the Hubble telescope.
During a Non-Advocate Review in January of 2007, nine of the ten technical development items in the project passed. The project's risk management team determined that these technologies had reached a mature stage and could safely be eliminated. The MIRI cryocooler, the final piece of technology in development, reached maturity in April 2007. The beginning of the process that eventually led to the project's detailed design phase was this technology review (Phase C). Costs remained on track as of May 2007. The project finished its Preliminary Design Review in March 2008. (PDR). The Non-Advocate Review was completed in April 2008. A review of the Optical Telescope Element was completed in October 2009, and the review of the Sunshield was completed in January 2010. All other evaluations were completed.
The Mission Critical Design Review for the telescope was completed in April of that year (MCDR). A successful MCDR indicates that the integrated observatory can meet its mission's science and engineering criteria. Design reviews before MCDR were all included in this one review process. This process, known as an "Independent Comprehensive Review Panel," led to a re-scheduling of the mission's launch date from 2015 to 2018, following a review of the project's timeline following its MCDR. Although the JWST's cost overruns impacted other projects by 2010, the launch date for JWST itself remained intact.
The final design and manufacture of the JWST project were completed by 2011. (Phase C). Every aspect of the design, building, and operation is scrutinized in great depth, as is customary for a complex project that cannot be changed after it has been launched. The project broke new ground regarding technology and passed all of its design reviews. A telescope this huge and light in weight was not known to be conceivable in the 1990s.
Robotic arms were used to assemble the primary mirror's hexagonal components, which began in November 2015 and finished on February 3, 2016. On March 3, 2016, the second mirror was deployed. Extensive testing began as soon as the Webb telescope's final building phase was complete in November 2016.
Since NASA delayed JWST's launch in March 2018 due to the sunshield ripping during practice deployment and the sunshield cables not properly tightened, it has been pushed back to May 2020. An independent review board created after a March 2018 test deployment failure recommended delaying the launch by another ten months to March 2021 in June 2018. There were 344 single-point failures in the launch and deployment of the JWST, actions that could not be redone in the event of failure and so had to be successful for the telescope to function. Exactly 12 years ago, in 2007, the mechanical integration of the telescope was due to be finished.
JWST performed final testing at a Northrop Grumman facility in Redondo Beach, California, after construction was completed. The telescope was shipped from California on September 26, 2021, and arrived in French Guiana on October 12, 2021, via the Panama Canal.
The project's completion cost is projected to be US$9.7 billion, of which US$8.8 billion was spent on the design and development of the spacecraft, and US$861 million is set aside to support the mission for the next five years. According to ESA and CSA representatives, the two organizations will contribute around €700 million and CA$200 million to the projects they lead.
JWST has a history of substantial cost overruns and delays, partly due to external factors such as difficulty in deciding on a launch vehicle and additional cash for contingency. JWST had a budget of roughly US$4.5 billion in 2006, and US$1 billion was already spent on its development. NASA's Space Science Board conducted a feasibility study in 1984, indicating that a next-generation infrared observatory cost roughly $7 billion in 2006 (about $4 billion).
According to the original estimate of US$1.6 billion, the telescope would cost around $4.5 billion when it was formally approved for construction in 2008. Even though the mission passed its Critical Design Review (CDR) in the summer of 2010, Maryland U.S. Senator Barbara Mikulski called for an independent investigation into the project because of delays and cost overruns. The ICRP, which was presided over by J.P. Morgan Chase & Co., launched in late 2015 at the cost of $1.5 billion more (for a total of $6.5 billion), was the earliest possible date determined by Casani (JPL). According to these experts, this would have necessitated additional funding in fiscal years 2011 and 2012, and a later launch date would have resulted in a higher total cost.
According to the House Appropriations Committee's FY2012 budget proposal for NASA, the James Webb Space Telescope (JWST) program would be axed by approximately one-quarter of that amount, amounting to $1.9 billion. There had been a total investment of $3 billion, with 75% of the gear now in production. A subcommittee vote on the next day approved this budget plan. The American Astronomical Society and Maryland US Senator Barbara Mikulski both issued statements supporting JWST in response to the committee's allegations that it was "billions of dollars over budget and plagued by poor management." Several editorials in support of JWST were published in 2011 in the worldwide press. Rather than canceling JWST, Congress blocked new financing for the project at US$8 billion in November 2011.
In light of the Webb telescope's rising price and lengthy timetable delays, some scientists raised concern about the lack of funding for alternative astronomical projects. A 2010 Nature article referred to JWST as "the telescope that ate astronomy" because of its out-of-control budget.
Many flaws that plagued past big NASA programs have been found in JWST's budget and status reports. As a result of the telescope's repairs and further testing, the timeline was pushed back, and the prices went up even more.
JWST's launch has been postponed until May 2020 or later; NASA revealed on March 27 that the project's costs could reach US$8.8 billion. After negotiating a new launch window with the European Space Agency, NASA committed to delivering an updated cost estimate (ESA). The COVID-19 pandemic stalled the project in 2020.
After voicing concerns about rising costs, Congress upped the mission's cost limit by US$800 million in February 2019.
Since 1996, NASA, ESA, and CSA have worked on the telescope. In 2003, ESA's members approved participation in construction and launch, and an agreement was signed with NASA in 2007. As part of its full partnership, the European Space Agency (ESA) will provide an Ariane 5 ECA launch vehicle and a team of astronomers to support operations in exchange for access to the observatory and full representation. Aside from the Near-Infrared Imager Slitless Spectrograph and the Fine Guidance Sensor, the CSA will also supply operational support personnel.
More than a thousand scientists and engineers from 15 countries worked together to construct, test, and integrate the JWST. Participating in the pre-launch project will be 258 companies, governmental agencies, and academic institutions from around the world, including 12 Canadians and 21 British, 16 French, and 12 German institutions. The pre-launch project will be held in 12 European countries, including the United Kingdom, 16 France, and 12 German institutions. The post-launch operations of other NASA partners, including Australia, are or will be involved.
Several large telescope models of the JWST have been on display since 2005, including in the United States at Seattle (Washington); Denver (Colorado); Greenbelt (Maryland); Rochester (New York); New York City (New York); and Orlando (Florida); and elsewhere in France, Ireland, Canada, the United Kingdom, and Germany). Northrop Grumman Aerospace Systems, the primary contractor, constructed the model.
A full-scale model of the telescope was created for the Smithsonian Institution's National Air and Space Museum in Washington, DC's National Mall in May 2007. The model intended to give viewers a better understanding of the satellite's size, scale, and complexity and spark their interest in science and astronomy. To withstand gravity and weather, the model is made of aluminum and steel, and it weighs 5,500 kg (79 feet by 39 feet by 39 feet) and is 24 meters long, 12 meters wide, and 12 meters high (12,100 lb).
On display in New York City's Battery Park at the 2010 World Science Festival, the replica included Nobel Prize winner John C. Mather, astronaut John M. Grunsfeld, an astrophysicist Heidi Hammel as backdrops for panel discussions. The model was on show at SXSW 2013 in Austin, Texas, in March 2013. In addition to Comic-Con, TEDx, and other public venues, Amber Straughn, the project's deputy project scientist for science communications, has appeared at numerous SXSW events since 2013.
When Webb was launched and deployed, NASA's Where Is Webb? The website allowed the general public to track its journey [https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html]
To honor NASA administrator James E. Webb, who served as NASA administrator from 1961 to 1968, NASA administrator Sean O'Keefe decided to name the telescope after Webb in 2002.
In 2015, accusations were made about Webb's involvement in the "lavender scare," the US government's prosecution of federal employees accused of homosexuality in the 1950s. Roughly three-quarters of the American workforce was laid off as a result of the fear. Between 1950 and 1952, State Department workers; Webb served as undersecretary of state from early 1949 to early 1952. Acknowledging that claims against Webb stemmed from a fake Wikipedia quote, Hakeem Oluseyi said he could uncover no evidence that Webb participated in anti-gay discrimination. In an editorial piece published in Scientific American in March 2021, four scientists urged NASA to rethink the telescope's naming in light of Webb's alleged cooperation. The press was quick to hone in on the controversy. NASA will not rename the telescope; it will be announced in September 2021. To suggest Webb should "be held accountable for that activity when there's no evidence to even hint [that he participated in it] is an injustice," said O'Keef, who decided to name the telescope after Webb. The American Astronomical Society sent NASA administrator Bill Nelson two letters requesting NASA release a public report detailing their investigation. According to documents from a 1969 appeals ruling (regarding the 1963 dismissal of an employee), it was common practice at the agency to dismiss gay employees.
There are four main objectives for the James Webb Space Telescope:
Observation in the near-infrared spectrum rather than visible light can better achieve these objectives. Rather than measuring light at visible or ultraviolet wavelengths as Hubble does, JWST's equipment will focus on infrared wavelengths. JWST can detect wavelengths from 0.6 nm to 28 nm (equivalent to orange light and deep infrared radiation at roughly 100 K or -173 °C).
KIC 8462852, a star that was identified in 2015 and has a light curve that's a little out of whack, may be studied by JWST in the future. As a result of this, astronomers will be able to determine whether or not an exoplanet has methane as a biosignature.
JWST is in a halo orbit near the L2 point, but orbits around it rather than sit exactly at the L2 spot. At 1,500,000 kilometers (930,000 miles) from the Sun, the second Lagrange point (L2) in the Sun-Earth system, JWST is nearly four times further from the Sun than the Moon's orbit. Typically, it would take longer than a year for an object orbiting the Sun at a distance greater than Earth's. A spacecraft can orbit the Sun similarly to how long it takes to orbit the Earth at the L2 point. As the antenna is nearer to the Earth, data rates can be much faster for a given size.
Around the Sun-Earth L2 point, it travels in an inclined halo orbit with a radius that ranges from about 250,000 kilometers (160,000 miles) to 832,000 kilometers (517,000 miles), and it takes roughly half a year to complete the journey. L2 is merely an equilibrium point with no gravitational attraction. Therefore the halo orbit can be regarded as a controlled drifting to keep the spacecraft in a certain neighborhood of that point, rather than a true orbit. Station-keeping: 2.5 m/s per year from the overall 93 m/s v budget is needed. The observatory's propulsion system consists of two sets of thrusters. All station-keeping operations are designed to slightly undershoot the required thrust to avoid pushing the JWST beyond the semi-stable L2 point, a situation from which there would be no recovery. "We never want this boulder to roll over the crest and get away from Sisyphus [...] pushing this rock up the gradual slope near the top of the hill," said JWST Integration and Test Project Scientist Randy Kimble of the telescope's precise station-keeping.
JWST is the successor of the Hubble Space Telescope (HST) and the Spitzer Space Telescope since its primary focus is infrared astronomy. This new observatory will be able to see significantly more and much older stars and galaxies than any of those two. Cosmic redshift and improved penetration of obscuring dust and gas make infrared observations an important approach for this goal. This enables the observation of objects that are fainter and colder. Ground-based infrared astronomy is restricted to wavelengths where the atmosphere absorbs less strongly due to water vapor and carbon dioxide in the atmosphere. As a bonus, the atmosphere itself emits infrared radiation, which can obscure the object being studied. For infrared observations, a space telescope is a way to go.
Objects farther away appear younger because their light has had more time to reach observers. Because of the redshift caused by the expanding cosmos, infrared radiation makes distant objects visible even at great distances. With its infrared capabilities, the JWST can retrace our galaxy's evolution back just a few hundred million years.
Cosmic dust is more likely to scatter visible light than infrared radiation. If gas and dust were obscuring these regions in the visible spectrum, the infrared would allow us to study them. This includes molecular clouds where stars are born, the disks that form around the stars, and the cores of active galaxies.
Planck's law states that infrared radiation is emitted mostly by objects with temperatures less than several thousand degrees. As a result, infrared spectroscopy is more useful for studying objects cooler than stars. This comprises the interstellar medium, brown dwarfs, planets, comets, and Kuiper belt objects that will be studied by the Mid-Infrared Instrument (MIRI).
Infrared astronomy missions such as Spitzer and the Wilkinson Microwave Anisotropy Probe impacted JWST's development (WMAP). Mid-infrared spectroscopy, which can be used to study dust disks around stars and other objects, was made possible thanks to Spitzer. In addition, the WMAP probe found that the universe was "lit up" around redshift 17, highlighting the importance of the mid-infrared. They were launched in the early 2000s, just in time to impact JWST's design.
An initial budget of US$162.2 million was set aside for the Science and Operations Center (S&OC) at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, on the Homewood Campus of Johns Hopkins University. In this role, STScI will be in charge of the telescope's scientific operation and the distribution of data products to the astronomical community. STScI will process and calibrate the JWST data via the NASA Deep Space Network, which will then be available online to astronomers worldwide. Anyone can submit suggestions for observations, similar to how Hubble operates. Peer review panels will pick the projects to be observed in the future year each year from the submissions of astronomers. After one year of private access to the selected proposals, the data will be made available to the general public from STScI's online archive for free download.
The satellite's bandwidth and digital throughput are designed to function continuously at 5.42 megabits per second (Mbps) throughout the mission. Single-board computers handle the bulk of the telescope's data processing. Analog science data is converted to digital form using the proprietary SIDECAR ASIC (System for Image Digitization, Enhancement, Control, And Retrieval Application Specific Integrated Circuit). According to NASA, all the operations of a 9.1 kg (20 lb) instrument box will be contained in a 3 cm (1.2 in) package and will use only 11 milliwatts of electricity. This IC must utilize as little power as possible to maintain the low temperature necessary for optimal functioning of JWST since it is close to the detectors on the telescope's cool side.
Since launch, the sixth micrometeoroid attack on the C3 mirror segment occurred between May 23 and 25, 2022. It was detected on June 8, 2022, necessitating engineers' use of a mirror actuator to correct the damage.
As the roughly $10 billion equipment was put through its paces, the scientists and engineers who worked on it revealed their excitement and nervousness over the launch. At 12:20 UTC on December 25, 2021, an Ariane 5 rocket launched from the Guiana Space Center in French Guiana with the mission (named Ariane flight VA256). NASA administrator Bill Nelson declared it "a terrific day for planet Earth" after the mission's successful launch. Following an initial test run, the telescope was confirmed to receive electricity and began a two-week deployment phase. Future spacecraft could utilize an adapter ring to grab hold of the observatory and try to remedy its massive deployment issues. It was tethered to the Ariane 5 through this adapter ring. This means that astronauts cannot do things like replacing our instruments like they could with the Hubble Telescope. To get it into a Lissajous orbit around the L2 Lagrange point, the telescope was released from the upper stage 27 minutes 7 seconds after launch.
Launched at a speed slightly below that required to reach its final orbit, the telescope decelerated as it moved away from the planet's surface, allowing it to reach L2 at speed required to enter its orbit there. On January 24, 2022, the Hubble Space Telescope reached the point known as L2. Planned course corrections were made three times during the flight to alter its speed and direction. The sunshield must remain between the telescope and the Sun to protect highly temperature-sensitive instruments, so the spacecraft cannot turn around or slow down using its thrusters. The observatory could recover from underthrusting (going too slowly), but it could not recover from overthrust (going too fast).
In theory, the telescope will be in operation for five years, but its ultimate goal is to be operational for ten years or more. After a six-month commissioning period, the five-year science mission gets underway. Station-keeping, or fuel to keep the telescope in its halo orbit around L2, is necessary for JWST due to the instability of its L2 orbit. The Ariane 5 launch and the first midcourse correction were credited with conserving enough fuel onboard that JWST may be able to sustain its orbit for roughly 20 years instead of the ten years it was originally meant to carry.
After a successful launch, JWST was released from the rocket's upper stage 27 minutes later. As soon as JWST blasted off, it began deploying its array of solar cells and antenna, as well as its sunshield and mirrors. The Space Telescope Science Institute in Baltimore commands nearly all deployment procedures, save for two early automatic stages, the unfolding of the solar panel and the deployment of the communication antenna. It was meant to allow ground controllers to adapt or modify the deployment process in the event of an issue.
Launch rotation was closer to optimum than deployment plans had anticipated. Therefore the electricity-generating solar panel was deployed one and a half minutes following telescope separation from the Ariane rocket's second stage. A camera mounted on the rocket provided a live feed of the solar panel separation and extension.
Despite the solar arrays' deployment, a factory pre-set duty cycle in the array regulator module was established before launching restricted power output. The telescope's batteries were being drawn down at a higher rate than predicted, resulting in a higher than expected voltage. Solar panels were reset, and duty cycles were tuned to account for the real-world conditions observed, including array temperatures, to assure sufficient power delivery for spacecraft and science operations. Some of the shade deployment motors had temperatures that were higher than expected. It was determined that, while the motors remained within acceptable operational parameters, they needed to be rebalanced, and their attitude was altered to help them achieve their desired temperatures. Based on simulation results, this was done. The majority of forecast models predicted the operational evolution in space.
It's now 7:50 pm. The telescope's primary rockets began firing for 65 minutes on December 25, 2021, at approximately 12 am Eastern Standard Time (EST). This was the first of three scheduled mid-course corrections. The high-gain communication antenna was automatically erected on the second day and ready to use.
Webb's rockets fired for nine minutes and 27 seconds on December 27, 2021, 60 hours after launch, to perform the second of three mid-course adjustments needed for the telescope to arrive at its L2 location. Three days after Webb's launch in December 2021, mission controllers initiated the deployment of Webb's all-important solar shield on December 28, 2021. The sunshield's forward and aft pallet structures were successfully lowered thanks to commands from the controllers. The delicate shield membranes are first unfolded and extended before being lifted from the pallets by telescoping beams in the following stage.
On December 29, 2021, Controllers successfully extended the Deployable Tower Assembly, a pipe-like column that moved away from the telescope, its mirrors and scientific instruments, and the "bus" containing electronics and motors. It took six and a half hours to lengthen the assembly by 48 in (1,200 mm), which included numerous preparatory directives. After deployment, there was enough space between JWST segments for the sunshield to open up and cool the telescope to its maximum operating temperature. Unpacking the observatory has two further steps accomplished by controllers by December 30, 2021. The aft "momentum flap," a device that provides a balance against solar pressure on the sunshield, was deployed first, minimizing the need for thruster firings to maintain Webb's orientation and save fuel. The sunshield was exposed to space for the first time after the protective covers were removed and rolled up.
On December 31, 2021, the ground team lowered the "mid booms" from the left and right sides of the observatory, extending the five sunshield membranes from their folded stowage in the fore and aft pallets. Once the sunshield cover had fully rolled up, mission control delayed the deployment of the left side boom in the pointing direction of the main mirror. The scientists then proceeded to expand the booms after reviewing additional data. Only 3 hours and 19 minutes separate the left side from the right. Webb's sunshield took on a kite-like shape and expanded to its full 14-meter (47-foot) width with that final step. It was envisaged that the membranes would be separated and tightened over several days.
To cool down the slightly hotter-than-expected sunshield deployment motors after a rest on New Year's Day, the ground team postponed sunshield tensioning by one day. This gave them time to optimize the observatory's array of solar panels. In the sunshield, tensioning began on January 3 and was finished at 3:48 pm local time on January 3, 2022. EST. At 4:09 pm, the second and third layers started to be tightened. Eastern Standard Time (EST). The final two layers, four and five, were successfully tensioned on January 4 at 11:59 am EST.
The telescope's secondary mirror was successfully deployed on January 5, 2022, with a tolerance of one and a half millimeters.
The primary mirror's wings had to be unfurled as the final step in structural deployment. The three primary mirror segments in each panel had to be folded to fit the telescope into the fairing of the Ariane rocket for the launch of the telescope. NASA completed the port-side wing deployment and lock-in on January 7, 2022, and the starboard-side mirror wing deployment and lock-in on January 8, 2022. The observatory's structural deployment was completed with this step.
When JWST entered its final orbit at the Sun-Earth L2 point at 2 pm EST on January 24, 2022 (almost a month after launch), the third and final course correction occurred.
Mirror alignment began on January 12, 2022, while the ship was still in the passage. Their protected launch sites were shifted away from the primary and secondary mirror segments. It took about ten days to complete the alignment to align the 132 actuator motors, which are designed to fine-tune the mirror positions with microscopic accuracy (10-nanometer increments). For further safety and efficiency, only one actuator was moved at a time, and actuators were only used for brief periods, keeping overall speed to around 1mm per day. This maneuver also involved repositioning the 18 ROC actuators, which control the curvature of the primary mirror segments.
There will be roughly three months of commissioning and testing when the 18 mirror segments have been liberated from launch protection and fine-tuned and aligned to work as a single mirror. The telescope's performance and the precise forms of some components will alter microscopically as it cools, making commissioning more difficult. In addition, all of its remaining scientific instruments have been powered up for testing as of January 31, 2022, and heaters used to prevent water and ice condensation will be gradually switched off.
Each of the 18 mirror segments and the secondary mirror must be precisely aligned within 50 nanometers. If the Webb primary mirror were as big as the US, each section would be the size of Texas, and the team would need to line the height of those Texas-sized segments up with each other to an accuracy of around 1.5 inches.
Identification of certain portions of an image. Which segment image is created by moving one of the 18 mirror segments? The mirrors are angled to bring the images closer, so they may be analyzed in greater detail.
The first step in Segment Alignment is to move the secondary mirror slightly to defocus the segment images. A mathematical procedure known as Phase Retrieval is applied to the defocused images to ascertain the specific location errors of the segments. 18 well-aligned "telescopes" are then produced by adjusting the segment lengths. Although the parts don't form a single mirror, they work well together.
Stacking of images. Each segment image must be piled on top to gather all the light in one area. Image Stacking is the process of aligning all segment images so that they fall exactly in the center of the field. Coarse Phasing is made possible by this procedure.
Optical Alignment of the Telescope with the Instruments of View. After Fine Phasing, the telescope will be perfectly aligned in the NIRCam field of view. Now, the remainder of the instruments must be aligned as well.
With the help of a 1/6 scale model, mirror alignment has been practiced and perfected repeatedly. A brilliant star, HD 84406 in Ursa Major, is the target of NIRCam when the mirrors reach 120 K (-153 °C; -244 °F). To do this, NIRCam collects 1560 photographs of the sky (156 images with each of its ten sensors) and uses these wide-ranging images to establish where each section of the primary mirror is initially pointing in the sky. As a result of the primary mirror segments initially being considerably misaligned, a hazy image of the star field containing 18 different images of the target star will be produced. HD 84406's 18 photos are matched to their respective mirror segments, and the 18 segments are brought into an approximate alignment centered on the star ("Segment Image Identification"). Each segment is adjusted for its primary focusing faults using the phase retrieval technique, resulting in 18 unique but high-quality images from the 18 mirror segments ("Segment Alignment"). To form a single image, the 18 photos from each section are precisely overlapped before being reassembled ("Image Stacking").
A 50-nanometer operational accuracy, less than one wavelength of measured light, is required for mirror fine-tuning now that they are perfectly positioned for proper images. First, dispersed fringe sensing uses 20 pairs of mirrors to detect and correct most faults. Then specific optical elements are employed to introduce 4 and 8 waves of defocus to each segment's image so that practically all residual flaws may be detected and rectified ("Fine Phasing"). These operations are done three times each, and the telescope's Fine Phasing will be constantly monitored.
In the NIRCam field of vision, the telescope will be perfectly aligned after three Coarse and Fine Phasing rounds. All instruments will make measurements and calculate corrections based on identified intensity fluctuations in the acquired image, resulting in a well-aligned result across all instruments ("Telescope Alignment Over Instrument Fields of View").
This last set of Fine Phasing and picture quality checks on all instruments verify that any lingering faults from the previous phases have been addressed and eliminated ("Iterate Alignment for Final Correction"). It is now possible to acquire photos with the telescope's mirror segments aligned and in focus, and the procedure allows for the retesting of prior processes to verify accuracy.
NIRCam's first photons were detected on February 3, 2022, at 19.28 UTC, NASA reported in preparation for the alignment (although not yet complete images). NASA announced on February 11, 2022, that the telescope's primary mirror had located and imaged HD 84406 and that all segments had been brought into near alignment. Phase 1 alignment was finished on February 18, followed one week later on February 25, by phases 2 and 3. However, this does not indicate that the 18 segments are operating together as a single telescope until all seven steps have been completed. Hundreds of other instruments are being set up and calibrated simultaneously as the primary mirror.
General Observers (GO), Guaranteed Time Observations (GTO), and Director's Discretionary Early Release Science (DD-ERS) programs are used to distribute JWST observational time. The GTO program guarantees to observe time for scientists who contributed to developing the observatory's hardware and software. A large percentage of the total viewing time will be allocated to the GO program, which is open to all astronomers. Similar to the Hubble Space Telescope proposal review process, GO programs are selected by a Time Allocation Committee (TAC).
It was reported in November 2017 that 13 Director's Discretionary Early Release Science (DD-ERS) programs had been selected after a competitive submission procedure by the Space Telescope Science Institute. After commissioning, these programs' observations will be collected over the first five months of JWST science operations. These 13 programs received a total of 460 hours of observing time, which covers a wide range of science topics, including the Solar System, exoplanets, stars and star formation, nearby and distant galaxies, and gravitational lenses, and quasars. A total of 242.8 hours of telescope time will be used by these 13 ERS activities (not including JWST observing overheads and slew time).
Webb's general science operations will begin on July 12, 2022, when the first full-color photos and spectroscopic data will be made available to the public for the first time. Nevertheless, on July 8, 2022, The Wall Street Journal released a preview test image from the JWST, which NASA indicated was slated for release.