The James-Webb telescope was successfully launched from Kourou

NASA’s James-Webb Space Telescope (JWST), designed to provide a glimpse of the first moments of the Universe, was successfully launched on Saturday, December 25 from the site in Kourou, French Guiana. This revolutionary infrared telescope at a cost of 9 billion dollars (7.9 billion euros), encapsulated in an Ariane-5 rocket, took off at 9:20 a.m. (1:20 p.m. in Paris).

“From a tropical forest to the temporal borders, James-Webb begins a journey towards the birth of the Universe”a NASA commentator professed as the two-stage launcher, fitted with two booster rockets, left its launch pad in a cloudy sky.

After a twenty-seven minute hypersonic journey into space, the 6-plus-ton instrument was released from the rocket’s top stage, about 865 miles (nearly 1,400 kilometers) above the rocket. Earth. It should gradually expand to the size of a tennis court over the next thirteen days as it cruises on its own. It will then take a month to reach its destination in orbit around the Sun, 1.5 million kilometers from Earth, or about four times the Earth-Moon distance. It will be protected from solar radiation by a thermal shield of five flexible sails which will dissipate the heat, lowering the temperature (which is 80 ° C) to – 233 ° C, telescope side.

Named after James Edwin Webb, NASA’s second administrator (1961-1968), the Webb telescope is about a hundred times more sensitive than its Hubble predecessor and is expected to revolutionize astronomers’ understanding of the Universe. It should make it possible to see the glimmers of “cosmic dawn”, when the first galaxies began to light up the Universe since the Big Bang, 13.8 billion years ago.

It will allow us to better understand the formation of stars and galaxies and to observe exoplanets, of which astronomers are discovering more and more specimens, in an attempt to identify, perhaps one day, other planets sheltering life. It should also allow a closer observation of Mars and Titan, one of Saturn’s moons.

Entry into service scheduled for June 2022

Imagined by NASA from the launch of Hubble in 1990 and built from 2004, with the collaboration of the European (ESA) and Canadian (CSA) space agencies, the JWST stands out in more than one way.

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The size of its mirror, with a wingspan of 6.5 meters, gives it a surface area and therefore a sensitivity seven times greater, sufficient to detect the thermal signature of a bumblebee on the Moon. Another difference: its mode of observation. Where Hubble observes space primarily in the domain of visible light, James-Webb ventures into a wavelength escaping the eye: near and mid-infrared. A radiation that any body, star, human or flower emits naturally.

This light will be studied by four instruments, equipped with imagers and spectrographs to better dissect it. Their development mobilized a plethora of engineers and scientists, under the leadership of American and European laboratories and industrialists. The prerequisite for the correct operation of the JWST is an ambient temperature so low that it does not interfere with the examination of the light.

For space, “Strong cooperation is essential to accomplish great things”ESA and NASA officials told Kourou. However, it will take several weeks to know if the telescope is ready for use. Its entry into service is officially scheduled for June 2022.

Le Monde with AFP and Reuters