James Webb Space Telescope

Sucessor to the Hubble Space Telescope, the James Webb Space Telescope (JWST) is the most complex and powerful telescope ever built. It is the most important space observatory of the next decade, and will be used by thousands of astronomers around the world.

A revolution in space astronomy

The Canadian FGS/NIRISS instrument on the James Webb Space Telescope. (Credit: NASA/C. Gunn)

Webb has a primary mirror composed of 18 hexagonal panels that is 6.5-metres in diameter, making Webb a huge space observatory. Its mass is about 6,500 kg, and its sunshield is the size of a tennis court. In order to launch it into space, the telescope had to be folded up to fit inside the fairing of the Ariane 5 rocket that launched it into space on the morning of December 25, 2021. The telescope then unfolded in space, like a flower, over 14 days en route to its final destination.

Located 1.5 million kilometres from Earth in the dark and freezing cold of space, the Webb telescope discovers and studies objects thousands of times fainter than could be detected with telescopes before it. Unlike the Hubble Space Telescope, which scans the visible universe, Webb is optimised to observe infrared light.

Four instruments are available on the Webb telescope, including the Canadian FGS/NIRISS instrument. This Canadian “2 in 1” instrument is composed of the Fine Guidance Sensor (FGS), which will allow the telescope to orient itself with great precision, and of a scientific instrument, the Near-InfraRed Imager and Slitless Spectrograph (NIRISS). The FGS is equipped with two identical cameras, essential to the vision of the Webb telescope. Their images allow the telescope to determine its position, locate its celestial targets, and stay pointed so that it can collect high-quality data. The FGS guides the telescope with the incredible precision of one millionth of a degree.

Science Objectives

The Webb Telescope can study every phase of cosmic history. The science goals of the James Webb Space Telescope can be grouped into four main themes:

alien worlds, from those in our own Solar System to exoplanets;
galaxies through time;
the life cycle of stars, from their birth to their death;
the early Universe as it was only 200 to 300 million years after the Big Bang.

This artist’s rendering shows the scientific capabilities of the James Webb Space Telescope. With its large mirror and infrared sensitivity, Webb can peer into early galaxies, explore star formation, and measure the physical and chemical properties of exoplanets. (Credit: NASA/ESA/STScI)

More specifically, thanks to its unique capabilities, the NIRISS instrument will discover the most distant and oldest galaxies in the history of the Universe. It will pierce the dazzling glow of nearby young stars to reveal new Jupiter-like exoplanets. It will also be able to detect the tenuous atmosphere of small, habitable Earth-like planets, determine their chemical composition, and search for water vapour, carbon dioxide, methane, oxygen, and other potential biosignatures.

The partners

The FGS/NIRISS instrument was designed, built and tested by Honeywell Canada (formerly COMDEV) in Ottawa and Cambridge, Ontario. The Université de Montréal and the National Research Council Canada (NRC) provided technical contributions to the project, and the FGS research team provided scientific guidance. Canada’s contribution guarantees Canadian astronomers the use of a fraction of the telescope’s observing time.

The FGS/NIRISS science team was led by NRC’s John Hutchings at the beginning of the project. It is now led by René Doyon, Director of iREx and Professor in the Department of Physics at the Université de Montréal. The team includes scientists from NRC, St. Mary’s University, the Université de Montréal, the University of Toronto, York University, Cornell University, the Space Telescope Science Institute, University of Michigan, and University of Rochester.

The James Webb Space Telescope is an international collaboration between NASA, the European Space Agency, and the Canadian Space Agency.

The Webb Telescope and iREx

Some of the iREx researchers affiliated with the Université de Montréal involved in the Webb mission (Credit: A. Philibert/UdeM)

Several iREx members, led by our director René Doyon who is also the principal investigator of the Canadian Webb instrument, have been involved in the design of NIRISS. iREx researchers have secured 207 hours of guaranteed observing time in the early years of Webb operations, most of which will be used to study the atmospheres of exoplanets using transit, eclipse and phase spectroscopy. Nearly half of the Canadian time proposals for general observations in the first year of Webb are also led by iREx researchers. Our team remains very involved in the development and support of Webb data analysis algorithms through the work of researchers Loïc Albert, Étienne Artigau and Neil Cook. The Outreach Scientist for Webb in Canada is also our Deputy Director, Nathalie Ouellette.