According to the US space agency NASA, the last step in preparation for the commissioning of the "James Webb" space telescope has been carried out successfully.
Accordingly, the six-meter main mirror of the space telescope was fully extended, as the authority announced on Saturday (local time).
With this procedure the development phase is now concluded.
A few days ago the sun protection of the telescope was opened, then the mirror systems followed.
Today another "milestone" was reached, said Nasa boss Bill Nelson on Saturday.
The telescope, built jointly by space agencies in Europe, the USA and Canada, is intended to explore the oldest galaxies in space.
According to the authority, the two wings of the mirror plates were remote-controlled unfolded for days and finally anchored.
This is followed by a phase of five months with further alignments and calibrations before the actual mission can begin with the first recordings.
The telescope was launched on December 25th on board an Ariane launcher from the European space station Kourou in French Guiana.
The telescope is expected to fly 1.5 million kilometers into space and take about four weeks for this distance.
Scientists hope that the images will provide information about the time after the Big Bang, around 13.8 billion years ago, among other things.
The first data and images from the telescope are not expected until summer at the earliest.
According to the operator, the "James Webb" telescope was developed for around 30 years and cost around 10 billion dollars (8.8 billion euros).
It follows the “Hubble” telescope, which has been in use for more than 30 years.