James Webb Space Telescope: Things That Must Be Known

25th December 2021 is one of the special days for space lovers. NASA successfully launched it's giant space telescope called "James Webb Space Telescope(JWST)" on a mission to find the first star to light up the universe. The observatory was lifted skyward by an Ariane rocket from Kourou spaceport in French Guiana.

james-webb-vigyan-geeks
Source: nasa

Why Space Telescopes?

Ground-based telescopes must look through Earth's atmosphere, which is opaque in many infrared bands. Even where the atmosphere is transparent, many of the target chemical compounds, such as water, carbon dioxide, and methane, also exist in the Earth's atmosphere, vastly complicating analysis.

Why James Webb Space Telescope, there is Hubble right!
Existing space telescopes such as Hubble cannot study these bands since their mirrors are insufficiently cool (the Hubble mirror is maintained at about 15 °C (288 K; 59 °F)) thus the telescope itself radiates strongly in the infrared bands. Whereas James Webb will operate in a halo orbit around the sun-earth 2nd Lagrange or L2 point approximately 1.5million km beyond earth's orbit around the sun. 

By comparison Hubble's orbit is about 550m above earth's surface. This means any repair or hardware requirement can be easily sorted in Hubble and is very complicated to Webb. Also, In the course of travelling to this L2 orbit, Webb will have to unpack itself the folded configuration it adopted at lunch.


 
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Source: wikipedia

Webb Vs Hubble:

  • The James Webb Space Telescope is 100X more powerful than Hubble, which enables us to observe the apparent edges of the Universe.
  • The JWST will provide improved infrared resolution and sensitivity over Hubble.
  • Webb's Telescope is just half the mass of Hubble, but it's primary mirror, gold-coated beryllium reflector has 6 times the collecting area that of Hubble.
Why L2 is Chosen?
Objects near Sun-Earth L2 point can orbit the Sun in synchrony with the Earth, allowing the telescope to remain at a roughly constant distance with continuous orientation of its unique sunshield and equipment Bus toward the Sun, Earth and moon to block their heat and light and to maintain communications. This arrangement will keep the temperature of the spacecraft below the 50 K (−223 °C; −370 °F) necessary for faint infrared observations.

When Will Webb Reach it's Destination?
It probably reaches it's destination L2 orbit by the end of January 2022, if everything happens according to that of planned. 

Where is Webb? Here you can find the position of the James Webb Space Telescope.

Will update more interesting stuff about it in later posts. Make sure you're subscribed via push notifications and mail updates for much interesting posts.