NASA says James Webb telescope hit key milestone for 2021 launch

The James Webb Space Telescope has hit another key milestone paving the way for its launch next year. NASA detailed the achievement on Friday, explaining that the Webb team was able to unfold the telescope's sunshield and tension it. The sunshield will undergo the same process in space, kicking off a mission years in the making.

The James Webb Space telescope features a huge sunshield designed to protect the telescope by reflecting background heat and light from the Sun. By doing this, NASA will ensure the space telescope remains cold enough to make observations in infrared light.

The sunshield features five layers and stretches out to around the size of a tennis court, making the unfolding and tensioning process especially difficult. NASA Goddard Space Flight Center manager of the Webb telescope's sunshield, James Cooper, said:

Congratulations to the entire team. Due to Webb's large size and stringent performance requirements, the deployments are incredibly complex. In addition to the required technical expertise, this set of tests required detailed planning, determination, patience and open communication. The team proved that it has all these attributes. It's amazing to think that next time Webb's sunshield is deployed it will be many thousands of miles away, hurtling through space.

The difficult process involved sending orders to the hardware, activating a series of motors and actuators among thousands of other components to stretch out the shield. The effort was particularly tricky because unlike in space, Earth's gravity caused friction as a complicating factor. Performing the activity on Earth, however, reduced the risk that something unexpected would happen in space.