The James Webb Space Telescope continues its deployment in space. The observatory is unfolding its heat shield, which will effectively protect its scientific instruments from the effects of the Sun.
It is a new stage that began in James Webb’s long journey to his destination. More than 500,000 kilometers from Earth, the space telescope has begun deploying a new part that is crucial for its proper functioning: its sun visor, which acts as a heat shield against solar radiation. Unfolding the entire structure will take a few days.
James Webb deploys his heat shield
The American space agency announced on December 28 the start of this sequence in a stage point on its website. This first phase aims to extend the two structures – one in front of the telescope, the other behind – which will serve as support for the heat shield. The sun visor is still folded up at this stage: it will be unpacked later.
The heat shield deployment phase will take a few days – the final stages will occur in five days, starting December 29.
After the exit of the structure that will support the sun visor, the time will come for the unwinding of the heat shield, which consists of five layers of a metallized fabric of the kapton type, a polymer which has excellent thermal stability. Once the shield is in place, it will be stretched and the five layers will be detached from each other.
The heat shield will have a decisive role in protecting the observatory during its five years of main mission – and possibly beyond, if it is decided to extend its operational activity. Astronomical instruments must be preserved, leaving them at a very low temperature (-235 ° C). On the side of the face exposed to the Sun, it can reach up to 125 ° C.
These steps completed, it will then be around the secondary mirror to come out – an event that will take place on the tenth day of James Webb’s departure from Earth. Then there will be the primary mirror, on the twelfth day, then the string of segmented mirrors, from the fifteenth day. There are eighteen in all: this will be the longest part of the whole trip.