After 30 years, NASA’s biggest and most powerful spacecraft, the James Webb Space Telescope, has finally launched. This infrared space observatory is supposed to unravel all the unknown aspects of the universe and stars in a way that no one has ever imagined. Due to the massive size of the JWST, it was folded to fit inside the Arianespace Ariane 5 rocket and was launched on 25th December from ESA’s launch facility in Kourou, French Guiana.
The James Webb Space Telescope is a joint effort involving NASA, the European Space Agency, and the Canadian Space Agency. The overriding objective of the JWST is to allow scientists to observe and know about the evolution of galaxies, the formation of stars and planets, the solar system, exoplanetary systems, and many more. In short, JWST will help us understand the universe’s origins and everything we see in outer space. According to NASA, the JWST involved over 300 universities, organizations and companies across 29 U.S. states and 14 countries.
Planning and Development of James Webb Space Telescope
Astronomers were thinking about the next major mission even years before the Hubble launch. In 1996, a group of 18 members lead by astronomer Alan Dressler, proposed NASA to build a satellite telescope to study the skies using infrared light. Because incorporating infrared light with a space telescope will allow astronomers to see past dust and clouds.
Webb’s initial design proposals, known as the Next Generation Space Telescope at the time, already included a segmented mirror, a “foldable” design, and a massive sun-shield. In 1997, NASA decided to fund additional research to fine-tune the telescope’s technical needs.
In 2002, James Webb Space Telescope was renamed after the NASA administrator who supervised the Apollo program’s development. The flight science working group and the team in charge of building the Near-Infrared Camera were chosen by NASA (NIRCam). The European Space Agency’s Centre Spatial Guyanais (CSG) spaceport in French Guiana was chosen as the launch location in 2005.
By 2011, all 18 mirror segments had been completed and tested to meet the needed requirements. Webb’s various elements were built in a multitude of locales. They began to arrive to NASA’s Goddard Space Flight Center in Greenbelt, Maryland, between 2012 and 2013. Webb’s scientific equipment was put through a series of harsh temperature and vibration testing from 2013 to 2016. Between 2015 to 2016, all 18 of Webb’s individual mirrors were mounted on the telescope’s backplane structure to build the 6.6 meters (21.7 ft) mirror.
In 2017, the mirrors and other equipment were shipped to NASA’s Johnson Space Center in Houston. In 2018, communications tests were run from the Mission Operations Center at STScI to the telescope’s spacecraft on the ground in California. Then in 2019, the sun-shield and bus of Webb’s spacecraft passed acoustic, vibration, and thermal vacuum tests. For the first time, the James Webb Space Telescope is entirely folded, and it undergoes final environmental testing in 2021 to ensure that it can endure the shaking and jostling of the launch environment. Finally, the JWST was then shipped to the Guiana Space Centre for launch.
James Webb Space Telescope: Brief Mechanism
Consider fitting a giant mirror and a sun shield the size of a tennis court onto a rocket ship.
If that doesn’t seem impossible enough, imagine removing them from a capsule and unfolding them in space, that too without gravity and in the face of extreme temperatures. NASA and Northrop Grumman engineers incorporated this sophisticated deployment into the construction of the James Webb Space Telescope.
JWST’s most unexpected and critical component is the sunshield. The sun shield is the primary cooling system for the James Webb Space Telescope. JWST sunshield is about 22 meters by 12 meters in area. The sunshield is comprised of five carefully folded membranes with cables, pulleys, and release mechanisms. The mirrors and four super-sensitive instruments are nestled behind the sunshield that will be below 390 degrees Fahrenheit temperature. The sunshield isn’t just a simple cover, it was designed with a lot of thought. The material of the sunshield is super thin and light. Moreover, it’s strong enough to withstand meteorite bombardment.
At 44 feet long and 14 feet wide, the telescope is equipped with a 6.5-meter mirror. This will allow it to be able to acquire finer, deeper views of the cosmos than Hubble, and it will also be able to do it in a fraction of the time. The huge mirror on the James Webb Space Telescope will direct light from stars and galaxies to four cutting-edge pieces of equipment that will collect photographs and investigate the chemical composition of the universe.
For the launch, the mirror, which is made up of 18 hexagonal parts that are each 4.3 feet across, folds up like origami paper. Each of the 18 hexagonal pieces is constructed from beryllium, a lightweight metal that weighs just 46 pounds. Each of the 18 hexagonal-shaped mirror segments is 1.3 meters in diameter. Despite its vast size, the complete spacecraft weighs just 6.5 metric tons, compared to 11.1 metric tons for the Hubble. Small motors push carefully against the plates at the backs of the 18 hexagonal mirror pieces, moving and bending them with incredible accuracy until they form one big, flawlessly, smooth mirror. The mirror’s surface is gold-plated, giving it the characteristic of a yellow tinge.
The light reflected by the enormous mirror is focused onto a secondary mirror opposite the large mirror, and is coupled that’s supposed to be deployed in space. The light then enters the telescope through a hole in the middle of the huge mirror, where it is directed to the detectors by a tertiary mirror.
How Does JWST Differ From Hubble?
In April 1990, the Hubble Space Telescope was launched into low-Earth orbit. Many facts about the cosmos were unknown to scientists when they planned and developed the Hubble Space Telescope, the most innovative astronomical observatory of its time. Hubble will always be remembered for its inspiring views of the universe and collecting crucial data for scientists. Despite the Hubble and JWST being substantially different, Webb is often regarded as its successor. Let’s see some of the differences between the JWST and Hubble.
- Wavelength: The main difference between the Webb and Hubble is that – JWST is designed to detect predominantly infrared light, whereas Hubble sees the light primarily at optical and ultraviolet wavelengths. According to the fact sheet, Hubble can see light with wavelengths ranging from 200 nanometers (nm) to 2.4 microns, but Webb’s range will be from 600 nm to 28 microns.
- Size: Webb has a significantly bigger mirror than Hubble with a dimension of 21.3 feet against 7.8 feet, as well as cutting-edge detectors which can be used to view further into the infrared spectrum. According to a NASA’s information page, the Webb is meant to “see” things 10 to 100 times fainter than Hubble using its huge gold mirror and infrared light observation capabilities.
- Orbit: The Hubble Space Telescope circles the Earth at the height of 570 kilometers above the surface. Webb will orbit the sun 1.5 million kilometers away from Earth at the second Lagrange point or L2.
Moreover, infrared imaging resolution of JWST is important for viewing the universe’s furthest regions. The Hubble Space Observatory could only offer a reasonable estimate of an old galaxy’s age and chemical composition, whereas the JWST will provide a precise answer.
Expectation Regarding JWST
The telescope will spend the next five to ten years examining the development of the universe’s oldest galaxies, how they compare to today’s galaxies, the evolution of our solar system, and if life exists on other planets. Just like its predecessor Hubble Space Telescope, JWST is also supposed to take photos of celestial objects. According to the Space Telescope Science Institute, the best images from JWST will start to appear about six months after launch.
As per NASA, the James Webb Space Telescope will focus on four main areas: first light in the universe, assembly of galaxies in the early universe, the birth of stars and, lastly, the planetary systems.
- Early universe: This stage refers to the initial phases of the cosmos following the Big Bang.
- JWST will be a powerful infrared time machine that will peek back over 13.5 billion years to view the earliest stars and galaxies growing out of the early universe’s darkness.
- Assembly of galaxies: The spiral and elliptical galaxies we see today developed from many forms. To better grasp how galaxies form over billions of years, the infrared light of the JWST will allow astronomers to compare the weakest and oldest galaxies to today’s grand spirals and ellipticals.
- Formation of stars and protoplanetary systems: The infrared eyes of the JWST will be able to look straight through the huge clouds of dust, where stars and planetary systems are forming.
- Planetary systems and the origins of life: JWST will provide additional information about extrasolar planet atmospheres and may possibly uncover the building elements of life elsewhere in the cosmos. This would help scientists better forecast whether or not a planet is inhabitable or not.
How Much Has JWST Cost?
The JWST was expected to cost NASA $9.7 billion. Of that amount, $8.8 billion was spent on spacecraft development. The total lifetime cost incurred by NASA, adjusted for inflation to 2020, is roughly $10.8 billion.
The most powerful space telescope – the JWST, is undoubtedly one of NASA’s best gifts to astronomers. NASA has been working on this telescope and getting it ready for launch for more than three decades. The space observatory is intended to succeed NASA’s Hubble Space Telescope, which is currently in orbit around the Earth. One of the most thrilling prospects of launching a large, bold, new telescope into space is that most astronomers, scientists, and engineers will get to know brand new facts about the universe that’ll be transformational for the fields of science. And with this new found information, the human race can grow and prosper even further and can potentially leave our mark among the stars.
