The Observatory, who had left the Earth on December 25, reached his final orbit at 1.5 million kilometers from our planet. It must capture the radiation of the first stars and galaxies formed after the big bang.
Le Monde with AFP
Almost a month after its launch, the Space Telescope James-Webb reached its final orbit, at 1.5 million kilometers from the Earth, from which it may be able to observe the first galaxies of the universe, confirmed NASA Monday, January 24th.
He activated his thrusters at about 20 hours to reach the point of Lagrange 2 or “L2”, ideal for observing the cosmos. “Welcome home, Webb!”, Exclaimed the boss of the American space agency, Bill Nelson, in a statement.
“We took a step further towards the update of the mysteries of the universe. And I can not wait to see the first new images of the world by Webb this summer!”, Has he Added.
At this carefully chosen orbit, the earth, the sun and the moon will all be on the other side of its sun visor, which will make it possible to operate in the darkness and in a very cold, indispensable at the study of the first cosmic radiation via its infrared sensors.
This is the third time that the telescope has thus operated its propellants since its launch on a rocket ariane 5, on December 25th.
A mission of twenty years
The high impulse supplied by the rocket had indeed been systemally minimized to prevent the instrument from exceeding its objective, without real hope of return, and it still owed, by small successive pushes, to place itself of itself .
The duration of the mission could be twenty years, according to Keith Parrish, one of the project managers. A possibility, which is not considered for the moment, would be a future mission goes into space to feed the fuel telescope.
The James-Webb telescope, whose cost for NASA is estimated at $ 10 billion, is one of the most expensive scientific equipment ever constructed, comparable to its hubble predecessor or the immense particle accelerator of the CERN.
But while Hubble was placed in orbit around the earth, Webb gravitate in the area of the space called Lagrange 2 point, where the forces of attraction of the earth and the sun are counterbalanced by the centrifugal force of the telescope, allowing a stable trajectory with a lower use of fuel.
in permanent contact with the earth
The new telescope will not exactly be at the L2 point but will oscillate around him in “halo” at a distance similar to that of the earth and the moon, according to a cycle of six months.
Other spatial missions have previously been placed on L2, such as the Herschel Infrared Space Telescope developed by the European Space Agency or NASA satellite which already had to study the Big Bang.
James-Webb’s positioning will also allow him to keep in mind with the ground by the DEEEP Space Network, a network of three large antennas in Australia, Spain and California.
NASA had succeeded in early January to deploy the huge mirror of the telescope that will allow it to receive radiation emitted by the first stars and galaxies, formed more than 13.4 billion years, less than 400 million years after the Big Bang.
With the expansion of the universe, this light still travels more way to reach the observer, and doing it “blushes”. As the sound of an object that moves away, the luminous wave stretches and passes from the frequency visible to the naked eye to that of the infrared.
Explore the exoplanets
Or, Webb, unlike Hubble, is equipped to perceive these infrared signals, which will allow it to see not only older objects, but also the clouds of interstellar dust that absorb the light of the stars and hide them. Hubble.
It must also take a big step in the exploration of exoplanets, orbit around other stars as the sun. It will examine their atmosphere, in search of conditions conducive to the appearance of life.
Next step: His scientific instruments still have to cool before being very precisely calibrated. His first images should be transmitted in June or July.