NASA’s James Webb Space Telescope (JWST) has started one of the riskiest activities of its mission – deploying the sunshield (the two long structures on either side of the spacecraft) into position to keep the telescope cold enough to operate.
NASA stated on 28 December that the spacecraft controllers had begun a multiday process of deploying the sunshield by lowering two components known as Unitized Pallet Structures, one on the front and the other on the rear of the spacecraft. The front section was lowered into place at 11:51 p.m. IST, and the back structure roughly six hours later.
The mission’s estimated timeframe for the sunshield deployment procedure is to be complete by 2 January. However, project experts warned before the launch that installing the sunshield would be the most challenging part of the JWST’s total commissioning.
“The sunshield is one of those things that is almost inherently indeterministic. The sunshield has some risk to it,” said Mike Menzel, lead mission systems engineer for JWST at NASA’s Goddard Space Flight Center, during a November briefing.
A five-layer aluminum-coated Kapton sunshield is used in the constructions. The sunshield, once deployed, will prevent sunlight from reaching the telescope and its equipment, enabling them to cool to their operational temperature. Cold temperatures are essential for the telescope to perform properly for infrared studies.
However, lowering the sunshields of James Webb Space Telescope is only the beginning of the proceedings. Deployable Tower Assembly was the next phase, which is now complete. It keeps the telescope and the rest of the spaceship separate, allowing the telescope to function at 40 K (-233ºC or -388ºF). Again, the process of sunshield cover release is yet to complete.
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Image Credit: Drew Noel
All the processes are time-consuming and will take several hours to complete since there are a lot of intricate steps to be followed. “The actual motion to lower the forward pallet from its stowed to its deployed position took only 20 minutes, and the lowering of the aft pallet took only 18 minutes, the overall process took several hours for each because of the dozens of additional steps required,” the Webb blog explains.
“These include closely monitoring structural temperatures, maneuvering the observatory with respect to the Sun to provide optimal temperatures, turning on heaters to warm key components, activating release mechanisms, configuring electronics and software, and ultimately latching the pallets into place.”
Once the sunshields of James Webb have created a safe cooling environment, the mirrors themselves must deploy. Once completely unfurled, the telescope requires a fuel burn to reach L2, the Lagrange Point opposite the Sun from Earth where it will stay throughout its active life.
Because the launch and first course adjustments went so successfully, less propellant was consumed than initially thought. This could be used for orbital corrections and orientation adjustments in the future. Therefore, if all these deployment stages go as planned as well, a piece of great news is waiting for us – JWST could operate well beyond its designed operational life of 10 years.
What does this mean? We will observe the Universe in all its vibrancy LONGER!
References:
NASA Webb Blog
Know more about James Webb space telescope in this article: James Webb Space Telescope: A Successor to Hubble
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