The James Web Space Telescope (JWST), which has been waiting for thirty years for astronomers around the world to explore the universe in unparalleled ways, is set to reach its observation post on Saturday with an Ariane 5 rocket 1.5 million km from Earth.
Scheduled for a 32-minute window from 12:20 GMT shortly after takeoff from the Cayenne Space Center, JWST will become the most advanced cosmos-tracking device ever sent into space.
With the aim of shedding more light on two questions that plague humanity: “Where do we come from?” And “Are we alone in the universe?”.
13.8 billion years ago, when the first galaxies after the Big Bang began to illuminate the universe, see the “Cosmic Dawn” glow.
This will allow us to better understand the formation of stars and galaxies and to observe extraterrestrial planets that astronomers have discovered more and more models to one day identify other Earths.
James Webb follows in the footsteps of the Hubble Space Telescope, which revolutionized the observation of the universe: thanks to him, scientists discovered the existence of a galaxy black hole at the center of all galaxies or the presence of steam around outer planets.
Imagined by NASA since the launch of Hubble in 1990 and built in collaboration with European (ESA) and Canadian (CSA) space agencies since 2004, JWST differs in more than one way.
Its glass size, with wingspan of 6.5 meters, gives it a surface area that is seven times more sensitive, enough to detect the thermal signature of a bumblebee on the moon.
Another difference: its monitoring method. Where Hubble primarily observes space in the field of visible light, James Webb enters the wavelength escaping from the eye: near and middle infrared. Radiation emitted naturally by any body, star, human or flower.
Images and spectrographs are fitted to examine this light with four instruments and to distinguish it better. Their development has mobilized numerous engineers and scientists under the leadership of American and European laboratories and manufacturers.
Thanks to this, astronomer Pierre Ferruit, associate science director of the telescope for the ESA, explained in Paris, “When we look at the same objects (like the Hubble), we see new things.” For example, the first galaxies, objects that turned pale red from a distance. Or young star colonies, growing in the dust clouds of their nurseries. Or the atmosphere of extraterrestrials.
The prerequisite for the proper operation of the JWST is a low ambient temperature that does not interfere with light testing.
Hubble is about 600 km above Earth. At this distance, JWST becomes unusable, warming by its reflection on the sun and the earth and moon. It will be placed at the end of a month-long journey of 1.5 million km. The flexible shield of the five flexible sails protects it from sunlight, which dissipates heat and lowers the temperature on the telescopic side (80 °) to -233 degrees.
But before going there, the machine and its designers must achieve a real feat: its flawless deployment, consistent with continuous operation, for example, shield only, 140 opening mechanisms, 400 pulleys and nearly 400 meters of cables. .
This is because the observation deck, which is 12 meters high and has a shield equivalent to a tennis court, had to slip into Ariane 5’s cap. It will cost about ten billion dollars.
For these maneuvers, NASA has imposed strict cleaning measures to prevent contamination of telescopic glass, particles or charged air.
Finally, at an altitude of 120 km, a firing depressurization system designed by Arianespace was installed so that a sudden pressure change during detachment from the launcher would not damage the animal. “A + customer + exceptional, exceptional activities”, the ESA official explained in Kourou on Thursday.
After 27 minutes we will know if the propulsion phase of the aircraft is correct. This will further seal the cooperation between NASA and its European allies. ESA and NASA officials told Kourou that space needed “strong cooperation to do great things.”
However, it can take several weeks to find out if the telescope is ready for use. With the official entry into the service scheduled for June.