NASA's most powerful space telescope completed

NASA has successfully completed building its largest space telescope, which will be 100 times more powerful than the Hubble probe and may find the first galaxies that formed in the early universe.

The James Webb Space Telescope will be the successor to NASA's 26-year-old Hubble Space Telescope.

The Webb telescope's infrared cameras are so sensitive that it needs to be shielded from the rays of the Sun.

A 5-layer sunshield of the sizer of a tennis court will prevent the background heat from the Sun from interfering with the telescope's infrared sensors.

The five sunshield membrane layers are each as thin as a human hair.

The layers work together to reduce the temperatures between the hot and cold sides of the observatory by about 298 degrees Celsius. Each successive layer of the sunshield, made of kapton, is cooler than the one below.

Webb has been designed and constructed to withstand its launch environment, but it must be tested to verify that it will indeed survive and not change in any unexpected way.

The US space agency also made the first important optical measurement of James Webb Space Telescope fully assembled primary mirror, called a Center of Curvature test.

Making the same optical measurements both before and after simulated launch environment testing and comparing the results is fundamental to Webb's development, assuring that it will work in space.

"This is the only test of the entire mirror where we can use the same equipment during a before and after test," said Ritva Keski-Kuha, NASA's Deputy Telescope Manager for Webb.

"This test will show if there are any changes or damages to the optical system," Keski-Kuha said.

The most powerful space telescope ever built, the Webb telescope will provide images of the first galaxies ever formed, and explore planets around distant stars.

It is a joint project of NASA, the European Space Agency and the Canadian Space Agency.