Sciences. The James Webb Space Telescope is ready for takeoff

countdown. In less than a month, on December 18, an Ariane 5 rocket will blast off from the base in Kourou, French Guiana, with the most powerful space telescope ever built. intends to capture Hubble, Overtaken by a malfunction And at its maximum lifetime (in operation since 1990), the James Webb Space Telescope should usher in a new era of astronomical observation.

Why does this happen?

Because this telescope has been waiting for astronomers for nearly twenty years. In development since 1996, the James Webb Space Telescope (JWST) was initially scheduled to launch in 2007. But delays and technical issues built up, so much so that the project ended up becoming something of an Arlesian celestial watch.

Costs have also gone up. From an initial estimate of $500 million, they eventually came to nearly $10 billion. For the most part, it was painfully resolved by NASA, JWST’s chief engineer. But the European Space Agency (ESA) and its Canadian counterpart (CSA) are also closely associated with the project. In particular, Europe presented many tools. It will also ensure the launch of the telescope, Mid-October arrived by boat to the Guyana Space CenterUsing an Ariane 5 missile.

What is the purpose of this endoscope?

Among other things, look at the past of our universe. In astronomy, looking far is like looking into the past, where light or radiation from deep space can take billions of years to reach us. So studying the formation of the first galaxies, which appeared immediately after the Big Bang, is one of the main tasks of the JWST.

But the latter should also allow us to better understand the formation and evolution of galaxies, study the birth of stars and observe exoplanets – a new field of astronomical observation, which in recent years has experienced strong winds.

What are the differences with Hubble?

There is not much in common between the two space telescopes, moreover, they can be considered complementary. In Earth’s orbit, Hubble operates primarily in visible light. It is, roughly speaking, a giant astronomical telescope. On the other hand, the James Webb Telescope’s infrared instruments work, which makes it possible to study ancient objects with unparalleled accuracy. Light emitted from distant objects in our solar system They are turning red, making it impossible to observe with a conventional telescope.

The physiology of the two instruments is also quite different. Starting with the size of the mirror: JSWT is three times larger than Hubble. In fact, it is so large (6.5 meters in diameter) that engineers had to resort to segmented mirror technology. Without it, he would not have been able to fuse into a missile form. The JSWT mirror is actually a set of 18 mirrors, which unfold in space to form a kind of giant mirror. It also has a huge canopy with a length of 22 meters.

Where will he put himself?

It is impossible, like Hubble, which flies at an altitude of 570 km above our heads, to remain in orbit around the Earth. To avoid interference from Earth’s atmosphere, JSWT will move slightly further away. Once launched, it will determine the path of the L2 Lagrange point (More explanations on this site), which will be saved around. This imaginary point, where the gravitational fields of the Earth and the Sun cancel each other out, would allow it to remain in the same position relative to our planet and our star. The journey of about 1.5 million kilometers takes 29 days.

However, this situation has a drawback: at this distance it is impossible to send humans to repair the telescope, as was the case with Hubble, which was Myopia is revealed fully at first.. Suffice it to say that the scientific community risks holding its breath for the four weeks it will last and during the commissioning.