James Webb Space Telescope (JWST)

Context

• The James Webb Space Telescope(JWST) is scheduled to be sent into orbit no earlier than December 22.

About JWST

• It will be a large infrared telescope with an approximately 6.5-meter primary mirror.  
• The telescope will be launched on an Ariane 5 rocket from French Guiana in 2021.
• It will be the premier observatory of the next decade, serving thousands of astronomers worldwide and is considered the successor of the Hubble Space Telescope.
• It was formerly known as the Next Generation Space Telescope (NGST) but was renamed in 2002 after a former NASA administrator, James Webb.
  • Under his tenure, NASA launched over 75 space science missions, including probes that were sent to Mars and Venus.
• Purpose : 
  • It will study every phase in the history of the Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of the Solar System.

• Partners:

• It is an international collaboration between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).
• The NASA Goddard Space Flight Center is managing the development effort.

• Main Features:
  • These include a primary mirror made of 18 separate segments that unfold and adjust to shape after launch. 
    • The mirrors are made of ultra-lightweight beryllium. 
  • Webb’s biggest feature is a tennis court-sized five-layer sunshield that attenuates heat from the Sun more than a million times.
  • It has a cryocooler for cooling the mid-infrared detectors of other instruments. 

                  Image Courtsey: NASA

• Wavelengths: Visible, Near Infrared, Mid Infrared (0.6-28.5 micrometres)
• Location in space: Orbiting the Sun around the second Lagrange point (L2)

• It will be the largest, most powerful and complex space telescope ever built and launched into space.

Webb vs other space telescopes

• The Webb telescope is said to be the scientific successor to the Hubble Space Telescope and Spitzer space telescopes. 
• Webb has a larger primary mirror — about 2.5 times larger in diameter than Hubble’s mirror. 
  • Webb will operate much farther from Earth (1.5 million km away).
• The Kepler telescope launched in 2009 and retired in 2018 helped identify planets that are located in or near the habitable zone of other stars.
  • Kepler was “designed to be a “wide and shallow” survey telescope, while Webb is designed for “narrow and deep” focused studies with near and mid-IR imaging and spectroscopy.”
• Another large infrared telescope — the Herschel Space Observatory — built and operated by the European Space Agency was active from 2009 to 2013.
  • But Webb and Herschel are complementary. 
  • Webb will be sensitive to wavelengths from visible light to mid-infrared, while Herschel was sensitive in the far-infrared wavelength.

Source: IE