On December 25, 2021, the James Webb Space Telescope (JWST) successfully launched into space and will travel to an orbit almost 1,000,000 miles away from Earth. On January 4, 2022, a critical milestone in the scientific operation of the JWST was reached with the deployment of the tennis-court-sized sunshield. The sunshield will protect the telescope’s instruments from the light and heat emitted by the Sun, Moon, and Earth. Such protection is required in order for the telescope to succeed in its objectives.
The JWST will require another five and a half months of set-up before it begins collecting data, but scientists are already excited about the scientific questions that they hope to address using the telescope’s observations. For example, scientists hope to “see” the first stars and galaxies as they formed in the universe 13.5 billion years ago. Although the light emitted by these objects was in the visible and ultraviolet wavelengths, it has been red-shifted and will now be detected in the infrared. They also plan to determine the compositions of exoplanets in other solar systems using a technique known as transmission spectroscopy to compare them with the planets in our solar system and assess them for habitability.
The deployment of the sunshield occurred over the course of eight days and involved a series of complex steps that required not only unfolding the shield structure but also tensioning it. Overall, nearly 700 mechanical parts and eight motors contributed to a successful deployment. The sunshield comprises five layers. Each layer is incredibly thin but is coated with a reflective layer equivalent to a sunscreen with SPF 1,000,000! This protection will keep Webb’s scientific instruments stable enough to detect the faint infrared light now arriving from the earliest stars and galaxies. NASA provides live progress of the JWST here. READ MORE