By Sharan Mujoo
Since its launch in 1990, the giant Hubble telescope, named after one of the most important astronomers in history, has been providing stunning visuals from space. The 2.4-metre diameter mirror-laden telescope allowed for some of the most important breakthroughs in astrophysics, such as determining the rate of expansion of the universe. Despite its achievements, Hubble has its limitations. It operates mostly within the visible light spectrum, which limits its ability to look deeper into space.
A replacement is designed
Thus, in 1996 therefore, the Next Generation Space Telescope was conceived. It is now better known as the James Webb Space Telescope, after the famous NASA administrator. Touted as the formal successor to the Hubble, it is a combined effort by NASA, ESA and the Canadian Space Agency. Expected to launch from French Guiana by Spring 2019, the giant telescope boasts approximately 270 square feet of reflective area, about five times larger than Hubble’s. Costing an estimated $8.8 billion, the JWST was developed and manufactured by Northrop Grumman and Ball Aerospace & Technologies.
The primary mirror comprises 18 hexagonal segments made up of gold-plated beryllium. This allows for more light to be collected, thereby bringing in more astronomical information. The Webb will operate from orbit in the L2 Lagrangian Point, which is approximately 1.5 million kilometres from the earth. This positioning will put enough distance between the new telescope and the gravitational influence of the sun, earth and moon. The Webb will mainly be observing Infrared light, which can be mistaken as heat from the sun. Therefore, a heat shield will be placed behind the collecting mirrors which will protect the infrared detector from undesirable light waves.
Planned scientific mission
The JWST boasts of four high tech instruments. The Near Infrared Cam (NIRCam) will detect light from stars in galaxies and nearby planets. It will also have the ability to block bright light from objects, making dimmer nearby objects visible. The European Space Agency (ESA) will also be providing the Near Infrared Spectrograph (NIRSpec), which will able to see 100 objects simultaneously. The Mid Infrared Spectrograph (MIRSpec) will be onboard to detect light and take images of celestial objects which are distant and farther away. Finally, the telescope will also have a Fine Guidance Sensor (FGS/NIRISS), provided by the Canadian Space Agency. This will be responsible for maintaining the direction of the telescope while the Near-Infrared Imager and Slitless Spectrograph will look for signs of primitive light in the universe.
After it settles into orbit, which is reckoned to take 30 days, the telescope will be in a position to fulfil its scientific agenda. It is expected to be able to study every historical stage of the universe, from the first energy emissions from the Big Bang to the formation of subsequent solar systems and the evolution of our own. There is little doubt that the future of all branches of astronomy will greatly be influenced by the discoveries made by the JWST.
Although the telescope was expected to launch in 2018, integration challenges from various subsystems led to a delay. The budget also crossed a previous $4.4 billion estimated limit. This has led to increased scrutiny by the government, which has set up an independent review panel. NASA’s website quotes Eric Smith, the Program Director of the JWST, explaining the delays and giving a new launch date of spring 2019.“Webb’s spacecraft and sunshield are larger and more complex than most spacecraft. The combination of some integration activities taking longer than initially planned, such as the installation of more than 100 sunshield membrane release devices, factoring in lessons learned from earlier testing, like longer time spans for vibration testing, has meant the integration and testing process is just taking longer.”
The JWST project has now passed the 10-year mark. It is, without doubt, the biggest space exploration project so far. Given the many technical difficulties the project has faced at every stage of development, it would not be incorrect to say that it is a highly risky enterprise. That being said, it also has some of the best minds in the world at work. The potential reward of its success could be a turning point in the history of human discovery. The next decade could see the discovery of more habitable exoplanets, lifeforms and a better understanding of the underpinnings of this universe. The JWST, despite its challenges, is a giant leap forward.
Featured Image Source: Flickr
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