The National Aeronautics and Space Administration (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 the US space agency'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.
NASA 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.
NASA said an Ariane 5 rocket will launch it from French Guiana in October 2018.
'Today, we're celebrating the fact that our telescope is finished and we're about to prove that it works," Nobel laureate and Webb's senior project scientist John Mather said during a news conference posted on YouTube, adding that the new telescope will open up 'a whole new territory of astronomy'.
'We will see things we have not seen before because this telescope is much more powerful than even the great Hubble telescope,' Mather said, adding that 'If you were a bumblebee at a distance of the moon, we will be able to see you from earth, both by your reflective sunlight and by thermal radiation and heat you emitted.'
According to NASA, its engineers and technicians on Wednesday successfully completed the first important optical measurement of Webb's fully assembled primary mirror, known as a Centre of Curvature test, to measure the mirror's shape.
Next, the 6.5-metre primary mirror consisting of 18 hexagonal mirrors will go through a series of rigorous tests that will simulate the violent sound and vibration environments the telescope will experience inside its rocket on its way out into space.
The Centre of Curvature test will be repeated after the launch environment testing and the results compared to find if there are any changes or damages to the optical system.
NASA said the Webb telescope will be used to observe distant objects in the universe, provide images of the first galaxies formed and see unexplored planets around distant stars.
