All about the Telescope

The James Webb Space Telescope (JWST) is one of the most exciting space projects in the last few decades. As the largest optical telescope in space, JWST is capable of investigating fields of astronomy and cosmology that were once impossible to study. Launched on 25 December 2021, JWST is now in the Sun–Earth L2 Lagrange point, protected by a five-layer sunshield, where its 18 hexagonal mirror segments made of gold-plated beryllium, give it a light-collecting area six times that of the Hubble Space Telescope. JWST observes a lower frequency range, from long-wavelength visible light (red) through mid-infrared (0.6–28.3 μm), unlike Hubble, which observes in the near-ultraviolet and visible spectra. The telescope must be kept extremely cold, below 50 K (−223 °C; −370 °F), such that the infrared light emitted by the telescope itself does not interfere with the collected light.

Credit: NASA/Goddard Flight Center

The idea of a large infrared space telescope goes back decades, and space observatories were free from atmospheric absorption of infrared light. Space observatories opened up a whole new sky for astronomers. However, infrared telescopes have a disadvantage: they need to stay extremely cold, and the longer the wavelength of infrared, the colder they need to be. If not, the background heat of the device itself overwhelms the detectors, making it effectively blind. The JWST team overcame this by designing the spacecraft carefully, launching it to the Sun–Earth L2 Lagrange point, where it remains at a roughly constant distance, while its wide shadow-avoiding orbit ensures that it simultaneously blocks incoming heat and light from all three of the celestial bodies, including the Earth, Sun, and Moon.

The project was plagued with enormous cost overruns and delays, a major redesign in 2005 led to the current approach, with construction completed in 2016 at a total cost of US$10 billion. The high-stakes nature of the launch and the telescope’s complexity were remarked upon by the media, scientists, and engineers. The primary contractor for the project was Northrop Grumman, while the NASA Goddard Space Flight Center (GSFC) in Maryland managed the telescope development, and the Space Telescope Science Institute in Baltimore on the Homewood Campus of Johns Hopkins University currently operates JWST.

Named after James E. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs, JWST has the capability to view objects too old, distant, or faint for the Hubble Space Telescope. This enables investigations across many fields of astronomy and cosmology, such as the observation of the first stars, the formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets.

The James Webb Space Telescope is an incredible achievement and is set to take space exploration to new heights. With its incredible capabilities and the hard work of the team behind it, there is no doubt that JWST will bring new discoveries that will change our understanding of the universe.

Author: Zig Annedy