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About the James Webb Space Telescope

The James Webb Space Telescope is the most powerful space telescope ever built. Canada has contributed a scientific instrument and a guidance sensor to the massive observatory, which will enable breakthrough discoveries in astronomy.

Canada's contribution to the James Webb Space Telescope (Credits: Canadian Space Agency, NASA, Northrop Grumman, ESA)


Mission objectives

Webb is designed to:

Canada's role

The Canadian Space Agency (CSA) has provided the Webb Telescope with the Near-Infrared Imager and Slitless Spectrograph (NIRISS) scientific instrument and the Fine Guidance Sensor (FGS).

Thanks to the CSA's contribution, Canadian scientists are guaranteed observation time on the Webb Telescope and are among the first to benefit from Webb's powerful instruments.

How Webb works

Webb uses infrared light, which cannot be perceived by the human eye, to study every phase in cosmic history.

The telescope's four scientific instruments are specifically designed to capture infrared light, and are able to peer through cosmic dust to study colder or very distant objects.

There are many kinds of light all around us: the rainbow of light we can see, and several other types – like X-rays, infrared, microwaves, radio waves – that are not visible to the human eye.

Certain types of objects, such as planets and very distant galaxies, shine most brightly in infrared light. A variety of instruments have been built to capture these types of non-visible light and help study different celestial phenomena like exoplanets, red dwarf stars and black holes.

About the telescope

Webb is the result of over 20 years of planning and development. Several elements make the space observatory unique and help ensure it will meet its objectives:

Where is Webb?

In addition to orbiting the Sun, Webb makes a tight orbit around a point in space known as Lagrange 2, or L2. This point is located 1.5 million kilometres from Earth. Its distant location gives Webb an unobstructed view of the sky, and aids its ability to see much farther into the universe than the Hubble Space Telescope.

Position of the Webb telescope in relation to the Sun, Earth, and the Moon – infographic

The Webb Telescope orbits the Sun at a position called L2, located 1.5 million kilometres from Earth. (Credits: ESA, CSA)

Position of the Webb telescope in relation to the Sun, Earth, and the Moon - Text version

The graphic illustrates the second Lagrange point, or L2, which is 1.5 million kilometres from Earth, opposite the Sun. The Sun and Earth are 150 million kilometres apart.

Data sheet

Mirror diameter 6.5 m
Mirror collecting area 25
Sunshield dimensions 21.2 m × 14.6 m
Height (deployed) 12 m
Launch mass 6,500 kg
Launch vehicle Ariane 5 rocket
Launch site Kourou, French Guiana
Solar array power 2,000 W
Operating temperature -233.2 °C
Wavelength coverage Near- and mid-infrared light

The Webb Telescope's four scientific instruments are housed together in a metal frame located behind the telescope's gold mirrors. (Credit: NASA)

Mission partners

Webb is an international collaboration between NASA, ESA and the CSA.

NASA's Goddard Space Flight Center manages the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute operates Webb after launch.

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