No offense to Thomas Pesquet, in the small space industry, it is James Webb who is now the star. Not the late James Webb, NASA administrator in the 1960s and conductor of the Apollo program, but the space telescope that bears his name.
After more than ten years of delay and a budget now approaching ten billion dollars, the craft designed by American NASA, European ESA and Canadian CSA is all ready for launch. If all goes well, takeoff is set for next fall from the space center in Kourou, Guyana. If all goes well. Because this project is as pharaonic as it is complicated.
Technical problems and permanent delay
As early as 1996, NASA looked into a replacement for the Hubble Space Telescope, launched six years earlier. Estimated cost: around a billion dollars, a more than reasonable sum for such a project. The calls for tenders are launched, the engineers are working. In the meantime, the company initially chosen is bought by Northrop Grumman, and the construction of the telescope finds itself split between several actors. The bill climbs to around 4 billion, a much more realistic amount given the innovations.
→ MAINTENANCE. Jean-François Clervoy: “Humanity will one day have to learn to live elsewhere”
Then the problems accumulate. An aggressive solvent is used to clean valves, which are damaged and need to be changed. Wrong voltage is applied to transducers, rewiring needs to be done. The sun visor deploys poorly. Ariane 5, which is to send the telescope, has its own difficulties. So when, in July 2020, the American agency announced a new six-month delay due to coronavirus, the news was no longer surprising. And during this time, the budget swells. The American authorities are questioning the relevance of such a financial pit. Astronomers themselves worry, because each extension for the telescope is a cut in other budgets.
Observe the beginnings of the Universe and the birth of stars
« These unforeseen events are perfectly understandable if we remember that it is a completely new project, that everything had to be invented as the development progressed. », Defends a specialist at NASA. Because the James Webb telescope is an “extraordinary” mission: the largest telescope ever sent into space. “James Webb will be a formidable time machine to trace the origins of the Universe, galaxies and stars », says Günther Hasinger, director of science at the European Space Agency (ESA).
Its mirror, with a diameter of 6.5 meters and covered with a thin film of gold, should make it possible to observe further, in space and time. For comparison, the Hubble Telescope’s mirror was “only” 2.4 meters in diameter. ” The larger the mirror of a telescope, the more light it can collect and therefore observe distant objects, describes Pierre Ferruit, scientific co-head of the ESA mission. With James Webb, we are going to look at the first hundreds of millions of years of the Universe, but also the life cycle of stars, exoplanets and their atmospheres. ” A quarter of the observation time will be devoted to these planets outside the solar system.
It is the center of Baltimore, in the United States, which already takes care of the Hubble space telescope, which will be in charge of the operations. The first images are expected in spring 2022. The mission should last around ten years, depending on the fuel reserves to orient the mirror.
A telescope folded to fit into the rocket
Before we get there, there are still several crucial steps. Already transported by boat from the west coast of the United States to French Guiana. The launch then, even if Ariane 5 has largely demonstrated its reliability. Deployment finally, because such a large telescope does not fit like that in a rocket! James Webb’s main mirror will be on-board folded, with 18 hexagonal segments that will need to line up to function as one.
“The telescope will be put into orbit around a point of Lagrange, 1.5 million kilometers from Earth, well beyond the lunar orbit and much further than Hubble, reminds Pierre Ferruit. This will allow the entire sky to be observed over the course of a year. “ At this distance, there was no question of sending repairmen from space, as has been done with Hubble. Thomas Zurbuchen, in charge of NASA’s scientific missions, sums it up well: “We’ve pushed the boundaries of what we used to build, now every cog has to work. “