NASA's JWST Passes Sun Shield Test

The James Webb Space Telescope (JWST) has passed a new important test ahead of its planned 2021 launch, according to NASA. The telescope attained a significant milestone with a successful test of the spacecraft's sun shield.

All five layers of the telescope's sun shields were installed and deployed the same way it would be when the James Webb telescope is in space. The sun shield's outputs were described as "stunning" the first time it was used.

About the Sun Shield

The James Webb telescope carries a considerable number of technologies that enables astronomers to see parts of the universe that humanity hasn't studied. One of those technologies is the five-layer sun shield is created to preserve the telescope's delicate pieces from the Sun's heat and light.

The James Webb telescope will need to deploy the sun shield after it launches successfully to guarantee the machine's sensor and optics stay cool enough to operate as expected. It means experiments on Earth are needed to make sure everything will go as intended. According to NASA, the Webb team was tasked with testing the deployment and subsequent tensioning of each of the five sun shield layers.

NASA explained that every sun shield's layer is made from a polymer material coated with aluminum called Kapton. The coating is meant to bounce the heat away from the sensors and optics; something which is bounded by a "treated silicon coating" on two layers which is most exposed to ultraviolet radiation.

James Cooper, James Webb Space Telescope Sunshield Manager at NASA's Goddard Space Flight Center in Maryland, explained that the five layers are needed to block and re-direct heat to get the telescope down to required temperatures within the margin. The gap between the panels provides an additional insulating effect, he added.

The aeronautical agency said the sun shield looks like a kite whose size is as big as a full tennis court - but it can be carried into a rocket payload which measures 16ft in diameter. The Webb team, now that the deployment test is complete, has been tasked to fold the compact sun shield and is stowed in position so that additional tests could take place.

Keeping It Cool

The James Webb Space Telescope will observe the infrared light from faint, very distant objects. The telescope itself must be extremely cool to identify those weak heat signals. The tennis court-sized sun shield that acts like a parasol providing shade to shield the telescope from external sources of light and heat as well as from heat emitted by the observatory itself.

This sun shield will always be between the Sun, Earth, Moon, and the telescope. JSWT would be orbiting the Sun 1.5 million kilometers away from (but approximately in line with) Earth is the reason why the sun shield positioned that way.

The sun shield likewise provide a thermally, stable environment in addition to producing a cold setting. The setup is vital to maintain the proper arrangement of the primary mirror segments as the telescope changes its orientation to the Sun.