Even before the launch of the James Webb Space Telescope in 1990, astronomers began asking the question: What's next after Hubble?
In September 1989, the Space Telescope Science Institute (STScI) and NASA co-organized the Next Generation Space Telescope Workshop at STScI, bringing together more than 130 astronomers and engineers. The group proposed that NASA investigate the feasibility of a 10-meter, passively cooled, near-infrared telescope in a high Earth orbit or a 16-meter telescope based on the Moon to study high-redshift galaxies.
In 1996, an 18-member committee led by astronomer Alan Dressler formally recommended that NASA develop a space telescope that would observe the skies in infrared light, the wavelength band that allows astronomers to see through clouds of dust and gas and extends humanity's vision farther into space and further back in time. It would have a mirror with a diameter of more than four meters and operate in an orbit well beyond Earth's moon.
Three teams composed of scientists and engineers from the private and public sectors convened to determine if NASA could make the committee's vision a reality. All three concluded that the proposed telescope would work. NASA agreed in 1997 to fund additional studies to refine the technical and financial requirements for building the telescope. By 2002, the agency had selected the teams to build the instruments and the group of astronomers who would provide guidance for the construction. Also in 2002, the telescope was formally named the James Webb Space Telescope, in honor of the NASA administrator who led the development of the Apollo program.
From Vision to Reality
Engineers and astronomers innovated new ways to meet the scientific demands of the Webb telescope, as well as a mission to a distance not accessible from Earth. Unlike Hubble, astronauts will not be able to repair and upgrade the telescope.
Construction of Webb began in 2004. In 2005, the European Space Agency's Centre Spatial Guyanais (CSG) spaceport in French Guiana was chosen as the launch site, and an Ariane 5 rocket as the launch vehicle. By 2011, the 18 mirror segments were completed and tested to meet the required specifications.
Between 2012 and 2013, individual pieces of Webb, built in various locations, began arriving at NASA's Goddard Space Flight Center in Greenbelt, Maryland. In 2013, construction of the sunshield layers began. From 2013 to 2016, Webb's scientific instruments underwent numerous tests of extreme temperature and vibration. From late 2015 to early 2016, Webb's 18 individual mirrors were installed on the backplane structure to assemble the 6.6-meter (21.7-foot) mirror.
In 2017, the mirrors and scientific instruments were connected and tested, then sent to NASA's Johnson Space Center in Houston, Texas. Additional environmental testing of the coupled telescope and instruments assembly occurred in a giant thermal vacuum chamber at Johnson in 2017, weathering Hurricane Harvey in late August without schedule delays. Final assembly and testing take place in 2018 and 2019 to ensure Webb will perform its complex deployment and scientific mission perfectly once in space, as it will be farther than humans have traveled and cannot be serviced. On December 25, 2021 at 7:20 a.m. EST (1220 GMT), Webb was launched from CSG.
Webb Project Timeline
1989
The Space Telescope Science Institute (STScI) and NASA co-organize the Next Generation Space Telescope Workshop at STScI. The focus was on the scientific and technical capabilities of an observatory that would follow the James Webb Space Telescope after its decommissioning, which was estimated at that time for 2005.
1995_1996
An STScI committee recommends a significantly larger telescope capable of observing infrared light. NASA selects Goddard Space Flight Center and STScI to study the feasibility of the Next Generation Space Telescope. Three independent teams from government and aerospace industry determine that such an observatory is feasible.
1997
NASA selects teams from Goddard Space Flight Center, TRW, and Ball Aerospace to refine the technical and financial requirements of the telescope.
1999
Lockheed Martin, Ball Aerospace, and TRW (also partnering with Kodak and ATK) conduct Phase A mission studies, including preliminary design and cost analysis.
2002
- Based on two Phase A studies, NASA selects the TRW/Ball Aerospace design to continue into detailed Phase B design studies, which examine the performance and cost of the chosen design.
- The telescope is renamed from Next Generation Space Telescope to James Webb Space Telescope.
- In Phase B, TRW and Ball receive the observatory contract, but immediate changes follow. Northrop Grumman acquires TRW and works with Ball to develop the observatory during Phases B, C, and D.
- NASA selects the flight science working group and the team responsible for developing the Near Infrared Camera (NIRCam).
2004
Construction begins on certain parts of the telescope that require extensive, long-term work, particularly Webb's scientific instruments and the 18 segments of the primary mirror.
2005
NASA approves the use of the European Space Agency's Ariane 5 rocket to launch Webb into space.
2006
The scientific instrument teams for the Near Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) pass critical design reviews and begin construction of the flight instruments. All of Webb's essential technologies are successfully tested in flight conditions.
2007_2008
NASA subjects the Webb mission to review by internal and external groups. The internal preliminary design review and external non-advocate review conclude that the plans and designs have reached the maturity needed for NASA to commit to Phases C and D, which involve detailed design, procurement, testing, and assembly of the telescope and observatory components. Construction begins in earnest.
2009
The Integrated Science Instrument Module (ISIM) structure, built to house Webb's four scientific instruments, arrives at Goddard Space Flight Center for testing.
2010
Webb passes its mission critical design review, meaning the integrated observatory will meet all scientific and engineering requirements for its mission.
2011
Webb's mirrors are completed. They are coated with beryllium with a thin layer of gold and have passed cryogenic tests, which exposed them to the cold temperatures they will experience in space.
2012
Goddard Space Flight Center receives two of Webb's four scientific instruments, the Mid-Infrared Instrument (MIRI) and the Near Infrared Imager and Slitless Spectrograph (NIRISS), as well as Webb's Fine Guidance Sensor, from the European and Canadian space agencies. Webb's secondary mirror and the first three segments of the primary mirror also arrive at Goddard Space Flight Center from Ball Aerospace & Technologies Corp. Northrop Grumman and its partner ATK complete construction of the center section of Webb's backplane structure, designed to hold the telescope's primary mirror segments.
2013
The two side "wings" of Webb's backplane structure are completed by Northrop Grumman and ATK. The two final scientific instruments for Webb, the Near Infrared Camera (NIRCam) and the Near Infrared Spectrograph (NIRSpec), as well as the remaining segments of the primary mirror, are delivered to Goddard Space Flight Center.
2014
Manufacturing begins on the spacecraft parts (such as fuel tanks, gyroscopes, and solar panels). Cryogenic testing of the Integrated Science Instrument Module (ISIM), including the four instruments, begins to demonstrate instrument performance as well as the electronics used to communicate with the instruments.
2015_2016
Cryogenic testing of the Integrated Science Instrument Module (ISIM) is completed. The 18 segments of the primary mirror are mounted on the backplane, along with the secondary mirror and supports. The primary and secondary mirrors are integrated with the backplane and ISIM to create the unit known as the Optical Telescope Element.
2017
The Optical Telescope Element successfully undergoes cryogenic testing in a giant thermal vacuum chamber called Chamber A at Johnson Space Center.
2018
After successfully completing its final thermal vacuum test, the Optical Telescope Element is delivered to Northrop Grumman in Redondo Beach, California, bringing all of Webb's flight components under one roof. The first successful communications tests are executed from the Mission Operations Center at STScI to the telescope's spacecraft on the ground in California.
2019
For the first time, Webb's spacecraft element—the sunshield and bus—successfully passes acoustic, vibration, and thermal vacuum tests that simulate the rigors of the launch environment as well as the extreme vacuum of space. Engineers successfully connect the two halves of the Webb telescope—the Optical Telescope Element and the spacecraft—at Northrop Grumman.
2020
Webb folds completely for the first time and completes final environmental tests to prove it can withstand the jolts and jostles of the launch environment. Webb's sunshield also deploys for the last time on Earth.
2021
- Webb folds and stows for launch for the last time. STScI announces the selection of Cycle 1 General Observer programs, completing the science that Webb will perform during its first year in space. Webb is shipped to the Guiana Space Centre (Le Centre Spatial Guyanais, CSG) in Kourou, French Guiana, for launch.
- NASA's James Webb Space Telescope launches on December 25 at 7:20 a.m. EST on an Ariane 5 rocket from Europe's Spaceport in French Guiana.