NASA’s James Webb Space Telescope (JSWT) is scheduled to launch on Dec 24, 2021, from ESA’s launch site at Kourou in French Guiana on board an Arianespace Ariane 5 rocket.
The $10 billion James Webb Space Telescope — NASA’s largest and most powerful space science telescope — will probe the cosmos to uncover the history of the universe from the Big Bang to alien planet formation and beyond.
It will take approximately 30 days for the James Webb Space Telescope to travel a million miles (1.5 million kilometers) to its permanent home: a Lagrange point — a gravitationally stable location in space. The James Webb Space Telescope will orbit the sun at the second Lagrange point (L2). L2 is a spot in space near Earth that lies opposite from the sun, this orbit will allow the telescope to stay in line with Earth as it orbits the sun. It has been a popular spot for several other space telescopes, including the Herschel Space Telescope and the Planck Space Observatory.
According to NASA, the James Webb Space Telescope will focus on four main areas: first light in the universe, assembly of galaxies in the early universe, birth of stars and protoplanetary systems, and planets (including the origins of life.)
Once the JWST has launched, it will undergo a series of science and calibration tests including sunshield deployment, telescope deployment, instrument turn-on and telescope alignment. According to the Space Telescope Science Institute, the best images from JWST will start to appear about six months after launch. Though we may possibly be treated to some “first light” images slightly earlier.
James Webb Space Telescope: Key facts
Launch date: Dec. 18, 2021.
Cost (at time of launch): $10 billion.
Orbit: JWST will orbit the sun, around the second Lagrange point (L2), 1 million miles (1.5 million kilometers) from Earth.
Primary mirror size: 21.3 feet (6.5 meters) across.
The powerful James Webb Space Telescope is also expected to take amazing photos of celestial objects like its predecessor, the Hubble Space Telescope. Luckily for astronomers, the Hubble Space Telescope remains in good health and it’s probable that the two telescopes will work together for JWST’s first years. JWST will also look at exoplanets that the Kepler Space Telescope found, or follow up on real-time observations from ground space telescopes.
The James Webb Space Telescope is the product of an impressive international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency. According to NASA, the JWST involved over 300 universities, organizations and companies across 29 U.S. states and 14 countries. The nominal duration for the James Webb Space Telescope is five years but the goal is 10 years According to ESA.
James Webb Space Telescope science mandate
JWST’s science mandate is principally divided among four areas:
First light and reionization
This refers to the early stages of the universe after the Big Bang started the universe as we know it today. In the first stages after the Big Bang, the universe was a sea of particles (such as electrons, protons and neutrons), and light was not visible until the universe cooled enough for these particles to begin combining. Another thing JWST will study is what happened after the first stars formed; this era is called “the epoch of reionization” because it refers to when neutral hydrogen was reionized (made to have an electric charge again) by radiation from these first stars.
Assembly of galaxies
Looking at galaxies is a useful way to see how matter is organized on gigantic scales, which in turn gives us hints as to how the universe evolved. The spiral and elliptical galaxies we see today actually evolved from different shapes over billions of years, and one of JWST’s goals is to look back at the earliest galaxies to better understand that evolution. Scientists are also trying to figure out how we got the variety of galaxies that are visible today, and the current ways that galaxies form and assemble.
Birth of stars and protoplanetary systems
The Eagle Nebula’s “Pillars of Creation” are some of the most famous birthplaces for stars. Stars come to be in clouds of gas, and as the stars grow, the radiation pressure they exert blows away the cocooning gas (which could be used again for other stars, if not too widely dispersed.) However, it’s difficult to see inside the gas. JWST’s infrared eyes will be able to look at sources of heat, including stars that are being born in these cocoons.
Planets and origins of life
The last decade has seen vast numbers of exoplanets discovered, including with NASA’s planet-seeking Kepler Space Telescope. JWST’s powerful sensors will be able to peer at these planets in more depth, including (in some cases) imaging their atmospheres. Understanding the atmospheres and the formation conditions for planets could help scientists better predict if certain planets are habitable or not.
James Webb Space Telescope onboard Instruments
The JWST will come equipped with four science instruments that will enable observations in visible, near-infrared and mid-infrared (0.6 to 28.5 micrometers) wavelengths.
Near-Infrared Camera (NIRCam)
Provided by the University of Arizona, this infrared camera will detect light from stars in nearby galaxies and stars within the Milky Way. It will also search for light from stars and galaxies that formed early in the universe’s life. NIRCam will be outfitted with coronagraphs that can block a bright object’s light, making dimmer objects near those stars (like planets) visible.
Near-Infrared Spectrograph (NIRSpec)
NIRSpec will observe 100 objects simultaneously, searching for the first galaxies that formed after the Big Bang. NIRSpec was provided by the European Space Agency with help from NASA’s Goddard Space Flight Center.
Mid-Infrared Instrument (MIRI)
MIRI will produce amazing space photos of distant celestial objects, following Hubble’s tradition of astrophotography. The spectrograph that is a part of the instrument will allow scientists to gather more physical details about distant objects in the universe. MIRI will detect distant galaxies, faint comets, forming stars and objects in the Kuiper Belt. MIRI was built by the European Consortium with the European Space Agency and NASA’s Jet Propulsion Laboratory.
Fine Guidance Sensor/Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS):
This Canadian Space Agency-built instrument is more like two instruments in one. The FGS component is responsible for keeping the JWST pointed in exactly the right direction during its science investigations. NIRISS will scope out the cosmos to find signatures of the first light in the universe and seek out and characterize alien planets.
The telescope will also sport a tennis court-size sunshield and a 21.3-foot (6.5 meters) mirror — the largest mirror ever launched into space. According to ESA, the telescope’s mirrors are made from beryllium and are covered in a microscopically thin layer of gold to aid the reflection of infrared light. Those components will not fit into the rocket launching the JWST, so both will unfurl once the telescope is in space.
James Webb Space Telescope vs.Hubble Space Telescope
The James Webb Space Telescope is referred to as the successor of the Hubble Space Telescope.
Scientific advancement is all about “standing on the shoulders of giants” and the JWST will do just that, as its scientific goals were motivated by the results from Hubble.
The two space telescopes have different capabilities, whilst Hubble primarily observed the cosmos in optical and ultraviolet wavelengths (with some infrared capabilities.) The JWST will primarily look at the universe in infrared. Due to the expansion of the universe, light from distant objects shifts to longer wavelengths at the redder end of the spectrum — known as redshifted, according to ESA. The JWST will observe this infrared light in great detail and shed light on some of the oldest stars and galaxies in the universe.
Another big difference between the James Webb Space Telescope and the Hubble Space Telescope is that JWST will orbit the sun, whist Hubble orbits Earth. JWST will be too far away to be serviced, unlike Hubble which was accessed and serviced by space shuttle missions.
The naming of the James Webb Space Telescope
The space telescope was previously known as the Next Generation Space Telescope and was renamed the James Webb Space Telescope in Sept. 2002.
The JWST is named for former NASA chief James Webb. Webb took charge of the space agency from 1961 to 1968, retiring just a few months before NASA put the first man on the moon.
Although Webb’s tenure as NASA administrator is most closely associated with the Apollo moon program, he is also considered a leader in space science. Even in a time of great political turmoil, Webb set NASA’s science objectives, writing that launching a large space telescope should be a key goal of the space agency.
NASA launched more than 75 space science missions under Webb’s guidance. They included missions that studied the sun, stars and galaxies as well as space directly above Earth’s atmosphere.
Not everyone is happy with the choice of name for the space telescope. An online petition was set up by critics urging NASA to rename the telescope due to claims that Webb was complicit in discrimination against gay and lesbian NASA employees during his tenure. NASA has since said it will not rename the telescope despite complaints.