by Chaitanya Sharma

NASA’s new telescope, The James Webb Space Telescope, was launched on 25 December 2022 and bears the name of James Webb, an influential figure who was appointed by President John F. Kennedy to lead the space agency during the 1960s. A total of 10 billion dollars went into the project, with 9.5 billion going into building the telescope and the remaining into maintaining the mission for the next 5 years.

An artist’s representation of the James Webb Space Telescope in orbit

How does it work?

It builds upon the legacy of the Hubble Telescope’s imaging capabilities and the Spitzer Space Telescope’s ability to detect in mid infrared range (beyond the visible spectrum). To make the images circulating now, Webb used its infrared cameras to collect several “brightness images” in grayscale. Six filters each captured different wavelengths of infrared light. Each of the filters were assigned a colour based on their wavelength: the filter exposed for the longest time is assigned red, and the one exposed for the shortest time is blue. All the images are combined to display the composite colours in the images circulating.

The James Webb Space Telescope’s Deep Field

Parts of the telescope:

Golden mirror: Webb’s primary mirror is 6.5 metres wide. The mirror has 18 hexagonal gold-coated beryllium segments that can be adjusted individually.

Sunshield: To protect itself from the Sun’s heat, Webb has a tennis court-sized sunshield. To accurately and precisely detect faint infrared light from distant objects in the universe, Webb must be shielded from the strong infrared light emanating nearby from the Sun, Earth, and Moon. The sunshield’s five layers block the light from these nearby objects.

Deployment: Webb is so large – it is the largest telescope to date – that it needed to be folded up like a piece of origami to fit into the Ariane 5 rocket that launched it into space. It took Webb about two weeks to fully unfold, and two more weeks to travel to its final destination.

Instruments: In addition to the Canadian-made scientific instrument NIRISS, the Webb Telescope houses three other partner-contributed scientific instruments: NIRCam (NASA), NIRSpec (European Space Agency [ESA]) and MIRI (NASA/ESA).

JWST’s NIRCam

High-frequency radio transmitter: Large radio antennas spread out around the globe receive Webb’s transmitter signals and forward them to the Webb Science and Operation Centre in the Space Telescope Science Institute in Baltimore, USA.