The Origin Hunter
Before Earth was born, Before our solar system came into existence, How was our Universe Beyond time which we measure, what is the origin of Universe and more of these things were not clear but the new Engineering Marvel which took off on its mission on December 25 will surely answer these “The James Webb Telescope”. It took 25 years to complete the project and it costs a whooping amount of around 10 billion USD or 75000 crore Indian rupee! Well lets see what makes this project so costly and important in space exploration.
The James Webb Telescope is the most biggest, powerful and accurate Telescope ever build by humanity. The telescope is named after James E. Webb, who was the administrator of NASA from 1961 to 1968 and played an integral role in the Apollo program. It is meant to be the successor of our Hubble Telescope which gave us insight all of which are not even completely interpreted yet. It creates a new era in Astronomy, theories and findings based on the data from the telescope and already existing ones. Yes this telescope has the potential to alter the whole field!
Structure and Launch
The James Webb Telescope consists of 18 hexagon primary mirrors, secondary mirror and sensor. It also has a shield protecting it from the nearby Infrared radiations. It lifted off on European heavy lift rocket, Ariane 5. The mirrors are made up of beryllium and have thin gold plating. It also have thrusters to adjust its position.
The Telescope orbits the Earth and Sun at a distance of 1.5 million Kilometre from Earth at the Lagrange’s point 2, it is a collections of positions in space where a small object like satellite can stay in the same position relative to the gravitational bodies that it is travelling with. The advantage of staying at these points is that they require only less energy to maintain its position compared to any other point. There are 5 such Lagrange’s point between sun and earth. The Hubble telescope is just at distance of 500 km.
The rays are travelling for millions of km and red shift happens, so for catching these infrared rays the telescope has these hexagon mirrors. As its infrared telescope, there is a need to shield it from the heat of the sun and earth as it could alter the results. So, the Lagrange’s point 2 is selected as it is behind our earth and less solar energy is transferred. Also the mirror side require a temperature of -233 degree celsius to work.
The shield used is made up of Kapton, a high performance lightweight plastic. There are 5 such layers which also contains aluminium in varied thickness to prevent all modes of heat transfer and design of the shield is done in such a way that the telescope side is always facing the dark side and radiations are funneled out. In addition it have a pulse tube cryocooler to cool down the system.
In order to fit this shield inside the rocket, the shield is folded along with the telescope mirrors. It is to be noted that area of the total mirror 25 metre square and shield being as big as a tennis court. As the number of folding increased joints and points of failure also increased. It is said that there were 300 points of failure during the unfolding process and if one point failed whole mission ends there. We cant physically access the telescope as its far away and a small error ends the game. The space debris and meteorites also posted a huge threat to the shield too.
Luckily and by gods grace all the stages completed successfully.
Working
As said earlier, there are 18 primary mirrors spanning about 25 square metre in total, traps the photon and send it to the secondary mirror placed(at focal point) in front of the sensor which then directs to the sensor on the centre of primary mirror. In every 60–64 millisecond, the photons are analyzed and adjusts the primary mirror accordingly. The motor system present on it can move all 18 mirrors.
The readjustment is done with the help of thrusters attached to various parts of it. Hydrazine is stored in it and with the help of catalyst thrust is made to change the orientation. It is due to this limitation mainly that the telescope is expected to have 10 year life span.
There are many researches done on refueling the telescope to extend its life. The James Webb telescope will be fully functional in about 5 months as there is a lot of testing to happen. The history of Hubble teaches us that.
The main aim of the telescope is to find about our origin it also looks out for extra terrestrial life in other galaxies and planets. It can study about the atmosphere of other planets using spectroscopic analysis. Its gonna change the total understanding of our universe and even we can hear that news that “We are not Alone”.
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