Stretched to the length of a tennis court, the five-layer solar shield of NASA's fully assembled James Webb Space Telescope has successfully completed the final series of large-scale deployment and stretch tests. These tests brought the observatory one step closer to launch, scheduled for 2021.
"This was one of the most important steps in preparing the telescope for launch in 2020," said Alfonso Stewart, James Webb Space Telescope Deployment Systems team leader at NASA's Goddard Space Flight Center. - "We were able to precisely synchronize the deployment movements of the screen in a very slow and controlled manner to maintain its 'kite shape. It is now safe to say that we are ready to repeat these operations in space."
This solar screen protects the telescope by reflecting light and background radiation from the Sun, Earth and Moon back into space. The observatory must remain cool in order to make observations of distant objects in the infrared, rays invisible to the human eye and felt as heat.
In the shadow of the sunshield, the James Webb Observatory's innovative systems and infrared sensors will allow scientists to observe distant galaxies and study many other intriguing objects in the universe.
Covered with a polymer film called kapton, the Webb Telescope's solar screen membranes were fully deployed and stretched in December at the facilities of Northrop Grumman in California, USA. That firm designed this solar screen for NASA.
During the tests, engineers sent a sequence of commands to the spacecraft's computers, activating 139 actuators, eight motors and thousands of other components, the combined use of which allowed the five solar shield membranes to unfold and stretch so that the screen took its final, working shape. One of the main difficulties of these tests was that the deployment was done in terrestrial gravity, leading to friction in the knots, whereas in microgravity this factor is virtually absent, said NASA representatives.
At launch, this solar shield will be wrapped around the observatory on both sides and placed in a coiled state inside the Ariane 5 launcher provided by the European Space Agency.