James Webb Telescope Could Reveal Secrets of the Universe
The world's most powerful telescope, James Webb Space Telescope (JWST), is set to launch this Christmas on 25 December, after the event has been delayed twice already. The telescope was under construction for the last 30 years with a total cost being almost $10 billion.
The telescope was initially planned to be launched on 22 Dec. However, it got delayed to Dec 24 after the technical team encountered an issue in communication between the observatory and launch vehicle system. The launch date has been then again delayed for the third time, this time due to bad weather at the site.
NASA partnering with Canadian Space Agency and European Space Agency, started construction on the telescope in 1996 and finished in 2016. It was named after James E. Webb who administrated NASA between 1961 to 1968. The James Webb was supposed to be built for $500 million, however, multiple delays in its production increased its total cost significantly.
Since the size of JWST is fairly large, the telescope will be put folded inside European Ariane-5, the rocket vehicle that will carry the telescope to space. The telescope will then detach itself from the rocket and continue its journey on its own. For the next two weeks, the telescope will start unfolding itself while it continues on its journey. Unlike Hubble Telescope, the JWST would not be orbiting the Earth. Instead, it will be orbiting Sun at a point L2 (Lagrange point 2) which is almost 1.5 million kilometers from Earth. L2 is a gravitationally stable point between Earth and Sun and it would require almost 30 days of traveling. The JWST's spacecraft bus has been filled with 168 hydrazine fuel and 133-kilogram dinitrogen tetroxide, which is enough to place the observatory on its orbit at L2 and keep it there for the next 10 years.
JWST comprises of OTE (Optical Telescope Element): mirrors etc. that will absorb the light received from space, ISIM (Integrated Science Instrument Module), sun shield: to protect the OTE and ISM from the heat of the Sun and maintain their working temperature (50K), and a spacecraft bus. The sun shield is made of 5 thin layers of Kapton which is a reflective material. Each layer is 1/1000 inch in thickness and is the size of the field of a tennis court. The ISM contains 4 infra-red instruments that will help process the light and rays absorbed by the mirrors. They include Mid-Infrared Instrument (MIRI), Near-Infrared Spectrograph (NIRSpec), Near Infrared Camera (NIRCam), and Fine Guidance Sensor Near-Infrared Imager and Slitless Spectrograph (FGS-NIRISS). The mentioned instruments inside ISM have a working temperature of -233 degrees Celsius. It is due to the fact that every hot or even warm object may radiate infrared rays and thus to absorb any slightest of infrared rays from the space, the instruments have to be really cold and must be protected from the heat of the Sun, Earn and Moon.
The JWST has a primary mirror which has a diameter of 6.4 m as compared to Hubble’s 2.4m. The primary mirror structure is made of 18 hexagonal mirrors that are made of beryllium and coated with gold. This will help the scientists on Earth to help accomplish one of the primary missions: to study the formation of galaxies and stars which came into existence when the Universe started. JWST with its advanced sensors will observe light emitted by the galactic bodies from the early ages of the Universe to explore the mystery that lies within that era. The telescope has an Earth pointing antenna to establish a connection between it and the Earth. A solar array has also been installed so that the solar energy can be used to convert to electricity to power the Observatory and the spacecraft bus where all of the computing and technical staff will take place. Soon with James Webb Space Telescope in orbit, scientists will explore the universe in a way never done and experienced before with a lot of surprises waiting to be found.
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