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Status: December 25, 2021 4:19 a.m.
The ultra-complex Webb space telescope launches today, a decade late. The gaze should go to the birth of the first galaxies. Wanted: Answers to the really big questions.
The James Webb Space Telescope is one of the largest scientific projects in history. With a 25 square meter mirror and highly sensitive infrared optics, this telescope will look deeper into the universe than any other before it. It was developed in the USA and Europe. The infrared telescope is intended to allow views far back into the past of the universe: to the birth of the first stars and galaxies shortly after the Big Bang.
The first work had already started in 1996. Estimated cost then: $ 300 million. Then planned start: 2011. Depending on the bill, this has now grown to more than ten billion dollars.
Most expensive instrument in space history
The telescope is as big as a tennis court and as high as a three-story house. With a diameter of 6.5 meters, its main mirror is almost three times the size of that of its legendary predecessor, the Hubble telescope. The Webb telescope only fits into the tip of an Ariane 5 rocket when it is folded up. And it takes a long time to unfold it again. The space telescope, along with the space shuttle and the LHC particle accelerator, is one of the most complicated machines that mankind has ever built.
Much more expensive than planned, construction time much longer: Technicians are lifting the so-called mirror assembly of the telescope in NASA’s Goddard Space Flight Center. (Archive image)
Image: Uncredited / NASA / AP / dpa
“James Webb” also sees behind clouds of dust
For more than 30 years, the legendary Hubble telescope has provided impressive images from space. In contrast to him, the Webb telescope works in the infrared range, as with thermal imaging technology. This enables the telescope to make things previously hidden behind clouds of dust visible, recognize molecules in the atmosphere of other worlds and receive the light of the very first stars and galaxies that formed only 300 million years after the Big Bang.
The new space telescope will also be able to discover exoplanets orbiting distant stars and examine their atmosphere. The search for the second earth will surely go a step further with this super telescope.
First unfold yourself like a butterfly
In order to put the new super telescope into operation, it has to detach itself from the tip of the rocket after take-off from the Kourou spaceport and exactly 33 minutes after take-off it has to start unfolding its solar cells in order to produce its own electricity. Otherwise its batteries will be empty after a few hours – and the mission will fail.
After unfolding the solar cells, additional parts are unfolded every day for almost two weeks. 130 mechanisms have to complete 300 unfolding steps until the telescope has unfolded – like a butterfly from its pupa. The whole thing is a very complex and risky maneuver. Nothing can go wrong here.
Service work impossible
The telescope is to be stationed 1.5 million kilometers from the earth, on a circular orbit around the “Lagrange point 2”. That’s almost four times farther than the moon and 25,000 times farther away than the Hubble telescope.
Service emissions there are impossible or almost impossible. “James Webb is in a completely different place where it’s incredibly cold,” says NASA Science Director Thomas Zurbuchen. Astronauts could not operate in this cold: “James Webb was built in such a way that it must and will work on its own.”
30 days of horror
There has never been such a complex process for commissioning a machine in space without the possibility of correction. In view of the risk inherent in the whole thing, NASA and ESA also like to speak of “30 Days of Horror” until the telescope has reached its destination fully unfolded.
Fuel for only 15 years
With no service emission from Earth, the telescope can operate far out in space for about 15 years until the fuel for its engines, with which it has to occasionally correct its flight path, runs out.
Only 15 years – that would be significantly less than with the Hubble telescope. But Hubble flies so close to Earth that the globe blocks Hubble’s view of space for half of the day.
The Webb telescope has an unobstructed view of space for a full 24 hours every day. Enough research time to look back at the beginnings of the universe and find further parts of the answer to mankind’s big questions: How did this crazy universe come about? And are we really alone in it?
James Webb Telescope is about to finally start
Arthur Landwehr, ARD Washington, December 24th, 2021 5:01 pm