January 10, 2022

The James Webb Space Telescope has completed its final deployments and was launched smoothly into space.

In the 1990s, serious plans began to replace the Hubble Space Telescope. Scientists needed a dark, cold environment that was quite far from Earth because collecting light from the faintest and farthest objects in the universe not only required a very large mirror, but also no background disturbance.

To this end, the scientists wanted to build a telescope that could make observations in the infrared part of the spectrum, since wavelengths there are longer than red light and are good for detecting heat emissions. These wavelengths are long enough that they are less likely to be deflected by interstellar dust.

This type of telescope must be very cold, and that’s why scientists built a tennis-court-sized heat shield that can keep light and heat away from the sun and prevent it from affecting the Webb telescope.

With the recent launch of the Webb Space Telescope, the telescope included 344 actions in which a single failure could bring it down. As a result, many scientists and engineers believe that the Webb telescope could still fail while in space.

However, this ultra-complex heat shield seems to be working: the temperature on the sun-facing side of the telescope is 55° Celsius, and already the scientific instruments on the sun-facing side of the sun shield have cooled to -199° Celsius, a temperature at which nitrogen is a liquid. The risks associated with using the telescope are widely known.

There is now great confidence that Webb will actually begin documenting its observations by the summer.

For more information, read the original story in Ars Technica.