It is almost time.
The James Webb Space Telescope will shortly be on its way to the L2 Lagrange point Sun / Earth and begin its scientific mission of at least five years. Really, it will happen.
Despite some delays since the program began in 1996 and a budget that has exceeded the original by several billion dollars, the start of the JWST appears to be within reach. That's when you consider almost a year away (the new scheduled start date is October 31, 2021) as near.
Many tests are performed prior to launch to ensure proper operation outside of the earth's gravity well, including deployment of the sunshade, which is used to keep the telescope at an operating temperature of ~ -220 ° C (~ 370 ° F).
This was recently tested with a successful full deployment and tension of the sun protection. In this deployment, 139 actuators, eight motors, and thousands of other components work together to complete the process. What could possibly go wrong? Everything went well, despite the myriad of potential problems, and the James Webb Space Telescope will soon be on its way to launch, provided all other tests go well.
“Congratulations to the entire team. Because of the large size and high performance requirements of Webb, deployments are incredibly complex. In addition to the required technical expertise, these tests required detailed planning, determination, patience, and open communication. The team has proven that it has all of these qualities. It's amazing to think that the next time Webb's sunscreen is used, it will be thousands of miles away and speeding through space, ”said James Cooper, Webb's sunscreen manager at Goddard. (NASA.gov)
During a recent test, engineers and technicians fully deployed all five layers of solar shading on the James Webb space telescopes. Photo credit: NASA / Chris Gunn
Sun protection is a critical part of the JWST. Without them, the telescope would effectively be blind, as the observatory captures infrared light given off by the heat of objects that formed 100 to 250 million years after the Big Bang. This infrared light is very weak and any nearby heat source would block the desired light.
In order to keep the telescope cool and to block out any light from the earth, sun or moon, the telescope will use a sunshade the size of a tennis court in space. This consists of five layers, each of which is the thickness of a strand of hair and is made of Kapton E, a commercially available type of polymer called polyimide, which is highly heat-resistant and stable. Each layer is coated with aluminum, and the two hottest layers that face the sun also have a treated silicon coating to reflect even more heat back into space (NASA / Goddard). There is space between the layers so that some heat can be dissipated to the outside between them so that the telescope and its instruments have cooled down enough through the last layer for the observatory to carry out its operations.
Since sun protection is such an important part of the JWST, one might wonder why it has to undergo such a delicate procedure in order to form itself into kite-shaped sun protection.
Why not start fully assembled?
Because it's just too big. The Ariane 5 rocket used for launch was selected in the early 2000s, and the JWST was designed and built with that in mind (NASA / Goddard, FAQ on James Webb Space Telescopes). And despite delays and budget increases, the James Webb Space Telescope will soon be lifted into space on an Ariane 5 rocket. This is a science that can improve our understanding of the very early universe, determine the properties of known exoplanets and possibly even observe for the first time a new class of Saturn-like planets with very wide orbits (NASA).
The universe is becoming even more accessible when Hubble made it with the launch of the James Webb Space Telescope. That is, when it starts … that will be by the end of next year at the latest.
A new look at exoplanets with NASA's upcoming Webb telescope
NASA's Webb Sunshield unfolds successfully and tensions itself in final tests
James Webb Space Telescope FAQ