James Webb Space Telescope: A brief history

The James Webb Space Telescope, or JWST for short, is a $10 billion engineering marvel. 

It took some of the greatest minds working at NASA, European Space Agency (ESA) and Canadian Space Agency (CSA) - and beyond - to work together for more than two whole decades on creating one of the most complex machinery in the world. 

It is no wonder that the first full-colour picture taken by JWST that was released a week ago prompted fanfare and exhilaration within the scientific community and the public at large. The release of the picture was presided over by President Biden, Vice President Kamala Harris, congressmen and other top NASA officials along with engineers and scientists.

But the journey to the heavens was not an easy one for JWST. 

The idea for what eventually became JWST was conceived of at a workshop at the Space Telescope Science Institute in September 1989, where scientists came together to discuss the successor to the Hubble Space Telescope (HST) - before the HST was even launched. 

Observing light

Initially called the Next Generation Space Telescope (NGST), scientists figured that to look back in time to observe the faintest light from when the first stars, galaxies and protoplanetary disks were formed and search for signs of life on distant planets, they would require a space telescope  different from the HST, which observed light in the visible and ultraviolet spectrum. 

They required a telescope that could see light in the infrared and mid-infrared spectrum.

Scientists believe that the Big Bang, the moment when the universe came into existence, occurred 13.8 billion years ago. And since then the universe has been expanding, exponentially at a faster rate. Due to the expansion of the universe, the earliest stars and galaxies since the Big Bang have moved away from us and the light that they have emitted (that has yet to bridge the cosmic void and reach us here on Earth billions of years later), has red shifted so much that they have become invisible to human eyes in a process called the Doppler Effect. 

Red shifting is what happens to light when the source of light moves away relative to you (or in this case, planet earth) and the wavelength of the light stretches and becomes longer, and the light that is emitted by the source is observed as turning red, or shifting towards the infrared spectrum.

A timeline behind the marvel 

The 1990s were spent on whether NGST would be feasible and on the technical aspects of the telescope and choosing the partners and international collaborators that would work on this project. 

NGST was officially named the James Webb Space Telescope in August of 2002, in honour of the second administrator of NASA who was instrumental to NASA's manned space flight program in the 1960s. 

The construction of JWST started in March of 2004 but by 2011, due to delays and budget re-evaluations, the US Congress held talks and accused NASA of mismanagement and threatened to kill the JWST project. 

Thankfully for the scientific community, NASA managed to keep the lights on for the JWST project and the construction of the JWST was completed in 2016.

The marvel's specifications 

The JWST looks unlike any other telescope ever built and for good reasons since it pushes the boundaries of science like never before. 

Its primary mirrors are 6.5m across (compared to HST's 2.4m) to capture as much light as it can from the furthest and faintest stars, galaxies and light bounced off of distant planets' atmosphere. 

The mirror is made up of 18 smaller hexagonal mirrors - all made out of beryllium, a material 6x stronger than steel but with a third of the density of aluminium, and coated in gold and joined together in a honeycomb pattern to act as one large mirror.  

It was built with such precision that according to Scott Willoughby, JWST Program Manager at Northrop Grumman, it has an error of 15 nanometer which is the size of a bacteria and are so sensitive they can detect the heat signature of a bumblebee on the moon if it were used from Earth. 

The light from the primary mirror is bounced around to the secondary and then to the tertiary mirrors until it finally reaches the Integrated Science Instrument Module (ISIM) which houses the crown jewel of JWST. 

The ISIM consists of two infrared cameras called Near-Infrared Camera, or NIRCam, and Mid-Infrared Instrument, or MIRI - which was created by ESA along with NASA's Jet Propulsion Laboratory, along with two spectrographs, Near-Infrared Spectrograph, or NIRSpec and Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph, or FGS/NIRISS - which was created by CSA. 

Together, these instruments housed behind the primary mirror can detect infrared red lights in the wavelengths from 0.6 microns to 28 microns, allowing us to see through dust clouds to look at luminous bodies behind it. And the spectrographs can, according to NASA, detect the physical properties of the bodies such as its mass, temperature and chemical composition, which allow them to study much more about what early stars were made out of and their evolution. The marvel can also study whether distant planets have the tell-tale signs of life by searching for elements and compounds given off by life forms in the atmosphere of these planets. 

These instruments are so sensitive that scientists knew it would not be feasible to operate the satellite in low Earth orbit like the HST, since the sensors detecting infrared (which is emitted by warm bodies) would be overwhelmed by heat from the Earth and the Sun. 

Instead JWST would have been sent on a voyage to orbit around a place in space called Lagrange point 2 (L2), 1.5 million km away from earth. Even there, the heat of the sun can heat up the instruments to more than 100 degrees Celsius. This is where the 5-layered passive cooling system of the tennis-court sized heat shield comes in. By facing the sun it provides shade for the optics part of the telescope and cools down the shaded region to -230 degree Celsius. 

The engineering of the telescope was further complicated by its massive size which meant that to fit inside the nose of the Ariane 5 rocket launched from Kourou in French Guiana, it would have to be folded down and unfurl in space when it reaches L2.

Given how far JWST is from us, there is no plan yet on servicing the telescope if things go wrong and with limited fuel it is expected to operate for five years, while NASA hopes to squeeze another 10 years out of the telescope. 

In fact, JWST has already been struck by a micrometeoroid and incurred damage; and NASA is assessing it.

Even with that setback, the latest images of SMACS 0723, Southern Ring Nebula, Carina Nebula, WASP-96b, and Stephan's Quintet released by JWST have already revealed things that were previously hidden to us. 

A photo of Southern Ring Nebula has shown a second dying star inside of the nebula which we previously couldn't see. The spectrograph aboard the telescope has shown that the exoplanet WASP-96b has water in its atmosphere and this is only the beginning. 

JWST will enable us to observe the first stars and galaxies, look at the evolution of galaxies by comparing the oldest galaxies with newer ones and to see how the first planetary systems were formed. 

And perhaps finally answer whether we are alone in the universe and, in the process, inspire generations of thinkers and maybe even tell us a bit more about our place in the universe.

Other great space telescopes

Hubble Space Telescope 

The Hubble is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. 

Hubble has recorded some of the most detailed visible light images, allowing a deep view into space. Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe.

Space telescopes were proposed as early as 1923, and the Hubble telescope was funded and built in the 1970s by NASA with contributions from the European Space Agency (ESA). Hubble was finally launched in 1990. 32 years later, it is still operational.

Chandra X-ray Observatory

The Chandra X-ray Observatory (CXO) is a Flagship-class space telescope launched by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2022. And as of 2022, the operation is ongoing.

The Chandra X-Ray Observatory is a NASA telescope that looks at black holes, quasars, supernovas, and the like – all sources of high energy in the universe. It shows a side of the cosmos that is invisible to the human eye. Chandra allows scientists from around the world to obtain X-ray images of exotic environments and help understand the structure and evolution of the universe.

After more than a decade in service, the observatory has helped scientists glimpse the universe in action. It has watched galaxies collide, observed a black hole with cosmic hurricane winds, and glimpsed a supernova turning itself inside out after an explosion.

Spitzer Space Telescope

The Spitzer Space Telescope was an infrared space telescope launched on 25 August 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy. It was the first telescope spacecraft to use an Earth-trailing orbit. 

Among many other accomplishments in its 16 years of operation, Spitzer discovered a giant ring of Saturn, revealed a system of seven Earth-size planets around a star 40 light-years away, and studied the most distant known galaxies.

Herschel-Planck Observatory

The Herschel Space Observatory was a space observatory built and operated by the ESA. It was active from 2009 to 2013, and was the largest infrared telescope ever launched until the launch of the James Webb Space Telescope in 2021.

The objective was to study cool objects across the Universe and in our Solar System, in particular the formation and evolution of stars and galaxies and their interaction with the interstellar medium. 

The observatory was capable of seeing the coldest and dustiest objects in space; for example, cool cocoons where stars form and dusty galaxies just starting to bulk up with new stars. It probed the formation of stars and galaxies across the history of the Universe.

Kepler mission

The Kepler space telescope is a retired space telescope launched by NASA in 2009 to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018.

Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets, in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets. Kepler observed 5,30,506 stars and detected 2,662 planets.