The European Space Agency (Esa), Nasa and Arianespace have announced that the James Webb space telescope’s target launch date is 18 December. It will be carried into space from Europe’s spaceport in Kourou, French Guiana, atop an Ariane 5 rocket, which has been designated flight VA256.

It will be the third Ariane 5 flight this year. After completing final tests about three weeks ago, the Webb is being transported by sea from the US and is scheduled to arrive at the launch site by the end of September.

Webb is a collaboration between Nasa, Esa and the Canadian Space Agency (CSA). It is 100 times more sensitive than the Hubble space telescope and works at longer wavelengths. Webb observes the infrared universe, whereas Hubble works at visible wavelengths. This will make the Webb’s science complementary to that of its predecessor.

The Webb’s infrared vision, among many other things, will allow it to look inside dust clouds where stars and planets are forming, look back further into the universe to see the very youngest galaxies, and take detailed atmospheric readings of planets around other stars. Like Hubble before it, astronomers expect Webb to make breakthrough discoveries in all branches of astronomy.