James-Webb telescope: how France helped build the next space revolution

The 24 December, an Ariane 5 rocket will send the James-Webb space telescope into orbit to take over from the famous Hubble. Initiated at the end of the years 1963, this technological gem will disrupt our view of the universe.

The space adventure is part of the long term. When the first milestones of the James Webb Space Telescope (JWST) are laid in 1980, its predecessor the Hubble Telescope has not even gone into space yet. But the future is prepared a long time in advance and it is finally 24 years later that this incredible tool weighing more than 6 tons, the size of a tennis court, is about to begin the mission.

Unless there is a last minute delay, the James-Webb telescope should depart from Kourou, Guyana, aboard an Ariane 5 rocket on 32 next December. It is one of those milestones that mark space history like the rover Curiosity on Mars or the robot Philae on comet Rosetta. A technical feat, the result of international collaboration, which will open a new side of space exploration.

To fully understand the impact of this eagerly awaited telescope, it suffices to observe what its big brother Hubble, launched into space in 1990. Most of the incredible photos of galaxies, supernovas or planets are taken from this telescope, although they are subsequently refined and colored for better rendering.

The pillars of creation, one of the emblematic photos taken by Hubble © Nasa Unlike telescopes on Earth, space telescopes installed in Earth orbit are not hampered by the atmosphere to get better shots, capturing both light visible to humans but also invisible spectra (infrared, gamma rays, etc.). It is to Hubble that we owe the proof of the existence of black holes, the refinement of the age of the universe or the idea of ​​the immense number of galaxies present in the universe.

Near 10 billions of dollars

James-Webb, named after the former NASA boss during the first step on the Moon, promises to take a new step. Its main mirror, a tool for capturing the famous light spectra, measures 6.5 meters in diameter (against 2.4 meters for Hubble). More powerful and located 1.5 million km from the Earth (against 580 km for Hubble), it promises to detect the tiny lights of the first stars to appear on the edge of our universe. It should also tell us more about how galaxies were formed. Finally, since each chemical component has a spectral signature, it will be able to determine whether an exoplanet has the conditions necessary for life (presence of methane, ozone, water, etc.) or even if it has traces of life.

The stakes are high, as is the budget: $ 9.7 billion, mainly disbursed by NASA ($ 7.9 billion). But Europe is not disconnected from the project since the European Space Agency (ESA) has provided one of the four instruments, the MIRI (Mid-InfraRed Instrument), which will make it possible to observe far infrared light. France was responsible in particular for one of the two parts of this instrument, the MIRIM imager (equivalent to a camera), developed between 2004 and 2009 by Cnes, CEA and several French laboratories.

Another French actor to take part in the adventure: Arianespace, responsible for sending the telescope into its distant orbit, 1.5 million km away. If the rocket
Ariane 5 is more in the habit of sending satellites near our planet, she was already responsible for launching in 2009 Herschel and Planck, two scientific satellites at the Lagrange L2 point, the same as the orbit point planned for James-Webb.

But this launch will remain that of the “decade” for the industrialist who has been working since several years on the adaptation of its launcher for this mission, in particular to ensure the deployment of the immense telescope. The latter will take about a month to go into orbit and another 5 months to start its work.

This trip will also be one of the last of Ariane 5, which will leave its place, running 2009 to the new Ariane 6 launcher. One last mission to end in style.

Thomas Leroy BFM Business Journalist