The success of Hubble Space Telescope after its repair mission in 1993 motivated the organizations to make a larger infrared light telescope that could see the past better. Hubble telescope system’s temperature interfered with the infrared radiation it received from the outer space. A new innovative next generation telescope was needed which was faster , better and cheaper. In 2003, NASA’s initial contract for James Webb Space Telescope(JWST) was $824.8 million collaborating with European Space Agency (ESA) , Canadian Space Agency(CSA). in 2005 after major redesign and re-planning , the mission cost reached a hefty amount of $4.5 billion. The telescope has a history of major cost overruns and delays due to backlashes from people and lack of funds.
Nevertheless, JWST launched on December 25, 2021 in Ariane 5 rocket from NASA Goddard Space Flight Centre, French Guiana. this orbiting infrared observatory will complement and extend the discoveries of the Hubble space telescope.
JWST will not orbit earth but will be move in a orbit of second Lagrange point(L2 point) which is about 1.5 million km away from the earth. The L2 point is sufficiently near to the earth allowing proper signal communication and the sun shield will prevent any infrared radiation coming from the Sun.
For it to make observation in the infrared spectrum , it must be kept under 50K (−223.2 °C) otherwise the infrared radiation from its system , the earth , moon and sun will interfere with the data. It uses a large 5 layered tennis court sized sun-shield to block that radiation and maintains its surface temperature. the single layer is as thin as a human hair and made with polyamide films . the membranes are coated with aluminium from both sides and a silicon doped layer facing the sun. the shield can be folded 12 times to fit in the Ariane rocket .
The Honeycomb mirrors
The primary optical mirror is beryllium reflector with area 25.4 m2 . gold is used to coat all the 18 mirror segments because it is a highly reflective material for infrared wavelength. The honeycomb pattern utilizes the best use of space available and are also deployable .
- Search for galaxies formed after the big bang . It can look 13.5 billion years into the past , about 400 million years after the big bang.
- How galaxies evolve.
- Observe the formation of stars.
- Measure physical and chemical properties of the planetary systems including the Solar System.
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