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Space probe

James Webb Space Telescope

The James Webb Space Telescope is a giant telescope in space with a golden mirror. It can see so far that it can catch light from the very first stars and galaxies.

▶ View the James Webb Space Telescope in the 3D model

Fact file

Type

Space probe

Launch

25 December 2021

Interesting facts about the James Webb Space Telescope

• Its main mirror is 6.5 m across and made up of 18 gold-coated hexagons – so large that it had to be folded up for launch.
• A sunshield the size of a tennis court keeps the telescope cold, at about -230 °C.
• It sees galaxies whose light has travelled more than 13 billion years to reach us – almost back to the beginning of the universe.

Frequently asked questions about the James Webb Space Telescope

The mission

A joint project of NASA, ESA and the Canadian Space Agency, successor to the Hubble telescope. It took more than 25 years to develop.

Technology and flight

It observes in the infrared – heat radiation that passes through clouds of dust. That is why it has to be ice-cold itself, otherwise it would “dazzle” itself.

Discoveries

It sits 1.5 million km from Earth at the Lagrange point L2, where it travels around the Sun together with Earth. It studies the first galaxies, how stars form and the atmospheres of planets around other stars.

For comparison

L2 is about four times as far away as the Moon – from there the telescope always has the Sun, Earth and Moon behind its sunshield.

Mission milestones

1. 25 December 2021Launch

   Launch at Christmas on a European Ariane 5 rocket from Kourou (French Guiana).

2. 24 January 2022Arrival at L2

   After a month and more than 300 delicate unfolding steps, the telescope reaches its position.

3. 12 July 2022First images

   The first colour images show galaxies and nebulae in sharpness never seen before.

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