James Webb Space Telescope


The James Webb Space Telescope (JWST) is a large, infrared space telescope with a 6.5-meter primary mirror. The planned launch date is October 2018 and will serve thousands of astronomers worldwide.

James Webb Space Telescope Picture

James Web Space Telescope will have a large mirror 6.5 m (21.3 ft) in diameter and a sunshield the size of a tennis court. Both the mirror and sunshade are folded up during launch and will open up when the telescope is in space. The space telescope will be located in an orbit about 1.5 million km (1 million miles) from the Earth.


The James Webb Telescope is an international collaboration between NASA, the European Space Agency and the Canadian Space Agency. The NASA Goddard Space Flight Center is managing the development effort. The prime contractor is Northrop Grumman Space Technologies. The Space Telescope Science Institute will operate the telescope after launch.

Several innovative technologies have been developed for James Webb Telescope. These include:

  1. Folding segmented primary mirror – adjusted to shape after launch
  2. Ultra-lightweight beryllium optics
  3. Detectors able to record extremely weak signals
  4. Microshutters that enable programmable object selection for the spectrograph
  5. A cryocooler for cooling the mid-IR detectors to 7K.


The James Webb Space Telescope mission aims are:

  1. To search for light from the first stars and galaxies which formed in the Universe after the Big Bang

2. To study the formation and evolution of galaxies and their connection to the Milky Way and our own Solar System.

3. To understand the formation of stars and planetary systems

4. To study planetary systems and the origins of life.

5. To study the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

The telescope will be launched in October 2018. It will be launched on an Ariane 5 rocket into an L2 orbit.


The Space Telescope’s instruments are designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 27 micrometers in wavelength.

There are four science instruments on JWST:

  1. NIRCam (Near Infrared Camera)

NIRCam is an infrared imager which has a spectral coverage ranging from the edge of the visible (0.6 micrometres) through the near Inradred (5 micrometres). The NIRCam will also serve as the observatory’s wavefront sensor, which is required for wavefront sensing and control activities.

The NIRCam is being built by a team led by the University of Arizona, with Principal Investigator Dr. Marcia Rieke. The industrial partner is Lockheed-Martin’s Advanced Technology Center located in Palo Alto, California.

  1. NIRSpec: (Near Infrared Spectrograph)

NIRSpec enables scientists to obtain simultaneous spectra of more than 100 objects in a 9-square-arcminute field of view.

NIRSpec is being built by ESA at ESTEC in Noordwijk, the Netherlands, leading a team involving Astrium GmbH, Ottobrunn and Friedrichshafen, Germany and the Goddard Space Flight Center: the NIRSpec project scientist is Dr Peter Jakobsen. The infrared detectors for both the NIRCam and NIRSpec modules are being provided by Teledyne Imaging Sensors (formerly Rockwell Scientific Company).

  1. MIRI: (Mid Infrared Instrument),

MIRI contains both a mid-infrared camera and spectrometer that has a spectral range extending from 5 to 27 micrometres, with a possible spectrographic coverage up to 29 micrometers. MIRI is being developed in collaboration between NASA and a consortium of European countries and is led by Dr. George Rieke (University of Arizona) and Dr Gillian Wright (UK Astronomy Technology Centre, Edinburgh).

  1. FGS: (Fine Guidance Sensor)

FGS is a very broadband guide camera that is incorporated into the cryogenic instrument payload in order to meet the image motion requirements of the JWST. This sensor is used for both “guide star” acquisition and fine pointing. The sensor operates over a wavelength range of 1 to 5 micrometers. It will be used to stabilize the line of sight of the observatory during science observations and also includes a Tunable Filter Imager module for astronomical narrow-band imaging in the 1.5 to 5 micrometre wavelength range.

The FGS (Fine Guidance Sensor) is led by the Canadian Space Agency under project scientist Dr John Hutchings (Dominion Astrophysical Observatory, Victoria).


James Webb Space Telescope (JWST) was formerly known as the Next Generation Space Telescope (NGST). JWST was renamed in September 2002 after NASA’s second administrator, James E. Webb.

26 June 2007: JWST Full-Scale Model Visits Dublin, Ireland.

6 June 2007: NASA and ESA Sign Agreements for Future Cooperation on JWST and LISA missions.

26 June 2007: Extra-Solar Planet Exhibition Unveiled at Goddard Visitor Center. Worlds Beyond was organized by the National Space Society in partnership with the James Webb Space Telescope’s education effort at Goddard.

14 June 2007: Construction Begins on the JWST’s Guidance Sensor and Imager.

April 2011: Cryogenic testing of a six-mirror array began.

July 2011: JWST mission was under review for cancellation by the United States Congress after about $3 billion had been spent and more than 75 percent of its hardware was either in production or undergoing testing.

November 2011: Congress reversed plans to cancel the JWST and instead capped additional funding to complete the project at $8 billion.

Specs and Info:

Wavelength: Infrared
Location: L2 Lagrangian point
Diameter: 6.5m
Launch Mass: 6,200kg
Collection Area: 25m2
Orbit Period: 1 Year
Focal Length: 131.4 m (431.1 ft)

Operate at Infrared Wavelengths

Due to a combination of redshift, dust obscuration and the low temperatures of many of the sources to be studied, the JWST must operate at infrared wavelengths, spanning the wavelength range from 0.6 to 28 micrometres. In order to ensure that the observations are not hampered by infrared emission from the telescope and instruments themselves, the entire observatory must be cold, well-shielded from the Sun so that it can radiatively cool to roughly 50 kelvin (−220 °C, −370 °F).

JWST is using a large metalized fanfold sunshield that will unfurl to block infrared radiation from the Sun, as well as from the Earth and Moon. The telescope’s location at the Sun-Earth L2 Lagrange point ensures that the Earth and Sun occupy roughly the same relative position in the telescope’s view and thus make the operation of this shield possible.

Cost History

In April 2006 the program was independently reviewed following a re-planning phase which began in August 2005 due to costs growth. The review concluded the program was technically sound, but that funding phasing at NASA needed to be changed. NASA rephased its JWST budgets accordingly.

The primary technical outcomes of the replanning are significant changes in the integration and test plans, a 22-month launch delay (from 2011 to 2013) and elimination of system level testing for observatory modes at wavelength shorter than 1.7 micrometres. Other major features of the observatory are unchanged following the re-planning efforts. In May 2007 the cost of the project was estimated at about US$ 4.5 billion.

Construction and Engineering

NASA’s Goddard Space Flight Center in Greenbelt, Maryland is leading the management of the observatory project.  Northrop Grumman Space Technology is the primary contractor for the development and integration of the observatory and are developing and building the spacecraft bus and sunshield.

Did you know?

JWST has a planned mass half that of the Hubble Space Telescope.

The James Webb Space Telescope (JWST) is a planned space infrared observatory, intended to be a significant improvement on the aging Hubble Space Telescope.

* A model of the telescope has been on display at various places since 2005: Seattle, WA; Colorado Springs, CO; Paris, France; Greenbelt, MD; Rochester, NY; Orlando, Florida and Dublin, Ireland (June 2007). The model was built by the main contractor, Northrop Grumman.

James Webb PictureWho was James Webb?

James Edwin Webb (October 7, 1906 – March 27, 1992) was the second administrator of NASA, serving from February 14, 1961 to October 7, 1968.

Related Books: 

Astrophysics in the Next Decade: The James Webb Space Telescope and Concurrent Facilities (Astrophysics and Space Science Proceedings) 2009th Edition
From Amazon.com

Planet Quest: The Epic Discovery of Alien Solar Systems by Ken Croswell
From Amazon.com

Distant Wanderers: The Search for Planets Beyond the Solar System by Bruce Dorminey
From Amazon.com


James Webb Space Telescope T-Shirt
From Amazon.com

James Webb Space Telescope Links:

The James Webb Space Telescope: NASA
James Webb Space Telescope (JWST): Youtube Videos


Picture of James Webb Space Telescope: 11/8/2007

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