James Webb Telescope: our time machine
- IDSS Space Society
- Jan 19, 2022
- 3 min read
Updated: Jan 31, 2022
NASA’s biggest gamble yet was a pure sight to watch; being launched into the utter darkness. The James Webb Telescope or the JWST was eye candy when launched. You don’t believe me? Okay, you be the judge.
After many delays, on 24th December of 2021, James Webb Space Telescope has taken its flight. As of today, it has been successfully deployed the starboard wing of its massive 6.5-meter mirror — marking the end of the observatory’s intense and critical deployment sequence.
The mirror on board is 6.5 m in diameter while the Hubble has 2.4 m thereby gaining an obvious advantage of collecting more radiation i.e., data. Even so, having a large mirror attains with its set of drawbacks as Sun is the nearest radiation source thereby most of the radiation collected will be of the sun but it is not the subject under study. Sun also causes the desired radiation sweep in the background. To avoid the above problem, the team working has come up with a solution as follows:
1. Placing JWST 150 million km away from the earth i.e., Lagrange point (L2).
2. Installation of 5 sunshield of the size of the tennis court with a design to fit in confined space.
But one might wonder, what exactly is the hype about? What makes it so special and dear? And one of the most pondered questions, why 17 years to get it in space?
Let’s start with the basics,
This wonder was named Next Generation Space Telescope but renamed as James Webb Space Telescope after James E. Webb, who was the administrator of NASA from 1961 to 1968 and played an integral role in the Apollo program.
It can observe from the optical end to the mid-infrared radiations (600 nm to 28.3 µm), this differs from Hubble as Hubble observes near-ultraviolet, visible, and near-infrared (0.1–1.0 μm) spectra. The problem arises due to the phenomenon of the red shift – the wavelength of light is stretched. Red shift transforms optical light into the infrared. Hubble can’t observe infrared and hence JWST is necessary to observe the beginning of “time”.
As Hubble mainly observes visible radiations it can’t penetrate the dust in the nebulae and give us a clear vision of the processes of formation of stars and star systems. This obstructed view will be subdued by the instruments installed in JWST like NIRCAM, NIRSpec, MIRI, NIRISS.
NIRCAM: It will take images from optical end radiation and the near-infrared (600nm to 5µm) and is developed by NASA.
NIRSpec: It will take a spectrum of wavelength 600 nm to 5µm and is developed by ESA.
MIRI: It will take spectrum and images of wavelength 5µm to 27µm, developed by ESA and NASA.
NIRISS: It will capture images and spectrum of wavelength 800 nm to 5µm, developed by CSA.
JWST was initially planned to launch in 2007 but due to many delays and cost overruns and a major redesign in 2005. The construction was completed in 2016 and the testing period started. Initially, in 2021 it was planned to be launched on 21st December but due to some communication issues between the observatory and launch vehicle system, it was rescheduled to 24th December.
JWST is the most expensive space mission, costing roughly 9.7 billion USD.
After 17 years of planning and executing, the James Webb Space telescope will hopefully bring new light on the past of our universe.
For live updates on JWST visit:
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