James Webb Space Telescope (JWST): Our eyes in space

 

James Webb Space Telescope (JWST) is soon going to be our eyes in space, giving us information regarding the old and distant objects, which were beyond the capability of the Hubble Space Telescope (HST). JWST is primarily designed for the purpose of infrared astronomy. In contrast to HST, which operated in the frequency range of near-ultraviolet, visible, and near-infrared (0.1 to 1.7 micrometre), JWST will make observations in a lower frequency range, visible range to mid-infrared range (0.6 to 28.3 micrometre). These enhanced capabilities to work in lower frequency and higher wavelengths are expected to provide JWST the necessary thrust that is required to observe deep into time and space. Due to this, it is expected to observe the first stars and the formation of the first galaxies, which was almost beyond the capabilities of HST. It is also expected that JWST can provide us with a detailed atmospheric characterization of the potentially habitable exoplanets, which is vital from the point of view of sustaining human civilization.

The development of JWST was led by the National Aeronautics and Space Administration (NASA) in collaboration with the European Space Agency (ESA) and the Canadian SpaceAgency (CSA). The telescope was launched on an ESA Ariane 5 rocket from the Kourou, French Guiana on 25^th December, 2021 at 12:20 UTC. The telescope entered orbit in January, 2022, and presently it is undergoing testing and alignment, which is expected to be over by June, 2022. It is expected to be operational from July, 2022 after which we will understand the true potential of the telescope which is considered to be a huge thermal camera by the scientific community. The telescope is named after James E. Webb, who was an administrator of NASA from 1961 to 1968, during which NASA presented us with some of the famous space programs like the Apollo, Mercury, and Gemini. The telescope is currently operated by the Space telescope science institute in Baltimore, USA.

The development of JWST began as early as 1996, when it was evident that we soon needed something better than the HST, to make serious advances in astronomy and space science. The initial planning was to launch the telescope in 2007, with a cost budget of 500 million US dollars. As expected, there were delays due to scientific and technological issues, budget issues, accidents during deployment, the COVID-19 pandemic, etc. Finally, the construction of JWST was completed in 2016 with a huge cost overrun of 9.7 billion US dollars. Followed by 5 years of extensive testing, the telescope is finally in its orbit and on the verge of being operational soon. This marks one of the greatest astronomical advances that we ever made. JWST is expected to present us with powerful eyes that will unearth important information hidden by the cosmological distances. It is expected to substantially alleviate our limitations to look deep into space and time. With proper data and information, we will be able to understand our universe better and fine-tune our theories by removing the presently existing issues. As of now, we wait eagerly for JWST to be operational and live up to its expectations. NASA has officially scheduled the release of the first official scientific images taken by the JWST on 12^th July, 2022 at 10:30 am EDT (1430 GMT).

We conclude the article with some of the salient features of JWST that makes it an instrument of hope for not only the scientists but mankind as a whole.

1) Mission duration:  5.5 years (primary mission), 10 years (planned), 20 years (expected).

2) Manufacturer: Northrop Grumman Corporation, Ball Aerospace & Technologies Corporation, L3Harris Technologies.

3) Mass of JWST when launched:  6161.4 kg  (13584 lb)

4) Dimensions:  20.197 m by 14.162 m  (66.26 ft by 46.46 ft)

5) Power:  2kW

6) Type:  Korsch telescope (minimum aberrations and wide field of view)

7) Primary mirror: 18 hexagonal mirror segments made of gold-plated beryllium.

8) Diameter: 6.5 m (21 ft.) (nearly three times that of HST)

9) Focal length: 131.4 m (431 ft.)

10) Focal ratio:  f / 20.2

11) Collecting area: 25.4 sq. m. (273 sq. ft.)

12) Wavelengths:  0.6 to 28.3 micrometre (Orange to mid-infrared).

13) Temperature:  Below 50 K (-223 degree centigrade,  -370 degree Fahrenheit) (very cold)

14) Location: deployed in a solar orbit near the Sun-Earth L2 Lagrange point about 1.5 million kilometres (930000 miles) from Earth.

15) Shield: 5-layer kite-shaped sun-shield protecting it from warming.

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By Prabir Rudra