In pictures | Successful takeoff for the James Web Space Telescope

The James Web Space Telescope (JWST), which astronomers around the world have been waiting for thirty years to explore the universe in unparalleled ways, set off on Saturday with the Ariane 5 rocket to reach its observation point 1.5 million km from Earth.

27 minutes after takeoff we know whether the propelled phase of the flight has taken place properly.

Departing from the Guyanese Space Center at 12:20 GMT, JWST will become the most advanced cosmos observation device ever sent into space. However it will take another month or so to reach the finish line.

Hoping to shed more light on two questions that plague humanity: “Where did we come from?” And “Are we alone in the universe?”.

Look at the lightning of the “Cosmic Dawn” when the first galaxies began to illuminate the universe from the Big Bang 13.8 billion years ago.

With a better understanding of the formation of stars and galaxies, it will be possible for astronomers to explore the exoplanets where most specimens have been discovered, perhaps locating another Earth one day.

James Webb follows in the footsteps of the Hubble Telescope, which made revolutionary changes in the observation of the universe: thanks to him scientists discovered the presence of water vapor around the galactic black hole or exoplanet in the center of all galaxies.

Predicted by NASA since Hubble’s launch in 1990 and built in 2004 in collaboration with European (ESA) and Canadian (CSA) space agencies, JWST differs in more ways than one.

Its mirror size, with a wingspan of 6.5 meters, gives it a surface area and is therefore seven times more sensitive, enough to detect a bumblebee’s thermal signature on the moon.

Another difference: its observation approach. Observing space in the light domain where Hubble is primarily visible, James Webb enters the wavelength that escapes the eye: near and mid-infrared. Radiation emitted naturally by any body, star, human or flower.

This is studied by four instruments equipped with imagers and spectrographs to better disperse the light. Their development has brought together many engineers and scientists under the leadership of American and European laboratories and industrialists.

Thanks to this, “by looking at the same objects (like Hubble), we see new things”, explained Pierre Ferroot, astronomer, scientific co-head of the telescope for the ESA in Paris. The first galaxies, for example, had their lights turned red by distance. Or young colonies of stars hidden in the dust clouds of their nurseries. Or the atmosphere of outer planets.

The ambient temperature required for the proper functioning of the JWST is very low, which does not interfere with light testing.

Hubble is about 600 km from Earth. At this distance, JWST is useless, heated by the sun and its reflection on the earth and moon.

It will be placed at the end of a month-long tour of 1.5 million km. And five flexible mats protected from solar radiation by a thermal shield that dissipates heat, lowering the temperature (80 °) towards the telescope to -233 degrees.

But before it can get there, the machine and its designers must achieve real merit: its flawless expansion, for shield only, with a series of operations with 140 opening mechanisms, 400 pulleys and almost 400 meters of cables. .

Because the Observatory, with its 12 meter high and tennis court-like shield, had to be folded to slip into Ariane 5’s cap. “The Encapsulation” was carried out with laser guidance without any damage to the device, the development of which cost a few tens of billions of dollars.

For these maneuvers, the NASA Telescope also imposed strict cleaning measures to prevent contamination by mirror particles or even charged air …

Finally, ArianeSpace installed a tailor-made firing depressurization system so that when separated from the launcher, at an altitude of 120 km, a sudden pressure change would not harm the beast. “Extraordinary actions, for an exceptional customer,” an ESA official in Kauro explained on Thursday.

It can take several weeks to find out if the telescope is ready for use. With official entry into the service scheduled for June.