NASA’s James Webb Space Telescope (JWST)

NASA’s James Webb Space Telescope is a true technological marvel, it is the largest, most complex, and most expensive space telescope ever built as of 2021.

This space observatory will peer deep into space looking out for the answers to some of the very foundational questions about the origin of the Universe and the existence of life.

It is going to look very far back in time, capturing light that has been traveling for 13.5 billion years, almost since the beginning of the Universe, letting us embrace the environment of the early Universe.

The Launch of the James Webb Space Telescope and all the controversies surrounding it were one of the main highlights of 2021.

It took off from Guiana Space Center in France atop of Ariane 5 Launcher on 25th December 2021.

This launch was not some regular space experiment, and there are good reasons why the James Webb Space Telescope is so hyped.

This integrated space observatory is a medium for 21st-century people, to proceed on their most important journey in space.

It will contribute some new important pages to our brilliant history of space exploration.

James Webb Space Telescope is the Earth’s Time Machine

James Webb Space Telescope Official Poster
James Webb Space Telescope Official Poster. By NASA/JPL-Caltech, Public Domain

When you look at the sky, you are essentially looking back in time, so in a way space telescopes are kind of a time machine.

This is because of light, you can see things when light strikes between them and your eyes, although it seems instantaneous, light takes time to travel.

For example, light takes around 8 minutes from the Sun to reach Earth.

So when you are looking at the Sun from Earth, you are actually looking at the Sun the way it was 8 minutes ago.


The Sun is around 150 million kilometers far away, and also then, we have different stars and galaxies throughout the Universe that are way farther away than the Sun.

So when you look at stars or galaxies from Earth, the more distant they are, the more time light takes to reach us from these celestial bodies.

In that effect, the JWST is a time machine, allowing us to peer deep into space looking out for the answers to some of the very foundational questions about the origin of the Universe and the existence of life.

It will open a new window on these exoplanets, observing them in wavelengths of light at which they have never been seen before and helping us gain new insights into their nature.

The James Webb Space Telescope will also help us understand how galaxies evolve over billions of years into grand spirals, like our own Milky Way galaxy.

It is very well-equipped to search for signs of habitability on distant planets and penetrate deep into the hearts of dust-covered stellar nurseries.

This telescope that can bring a revolution in the field of Astrophysics, the renowned James Webb Space Telescope, was named after James E. Webb, former administrator of NASA from 1961 to 1968.

Who is James Edwin Webb

James Edwin Webb
James Edwin Webb ran the emerging space agency from February 1961 to October 1968. He believed that NASA had to strike a balance between human space flight and science. Credits: NASA.

He had made major contributions to the Apollo moon program. James Webb is believed to be a supporter of space science.

It is claimed that Webb believed that the space program was more than a political contest.

He argued that NASA needed to create a balance between human spaceflight and science since such a combination would help the country’s institutions and aerospace sector grow.

Objectives of the James Webb Space Telescope

The fundamental necessity for JWST was to dive into the depths of the vague discoveries made by the Hubble Space Telescope (HST).

HST was able to lead the Scientists in different directions of space despite the limited technology used at that time.

So, primarily, JWST had to be better than HST.

Keeping these words, endless research and experiments had been undertaken to ensure JWST become the best telescope.

Discoveries by the Hubble Space Telescope & its Problems

It can capture images in Visible Light, Ultraviolet Rays, and also near-infrared wavelengths.

Hubble Space Telescope was able to resolve some of the very long-standing questions of astronomy.

It has contributed to major discoveries related to the expansion of the universe, solar system, mass & size of the milky way galaxy, and more.


How far back in time can the Hubble Space Telescope see?

For the record, the farthest galaxy Hubble was able to detect was GN-z11 which is 13.4 billion light-years away. At that time back in the past, the Universe was just 3% of its current age.

Problems with the Hubble Space Telescope

But among all these fascinating discoveries, the HST has one problem – It can not detect longer wavelengths.

It becomes a problem because light from the early Universe has been stretched out due to Hubble expansion.

Hence, HST was unable to see some of the first galaxies and their formation.

How is the James Webb Space Telescope going to help?

Cosmologists are interested in studying the foundations of the Universe and any of the existing Space Telescopes and Hubble can’t help them with it.

That’s where the 21st Century Hero, the JWST enters and steals the show. 

The JWST will be able to see the longer wavelengths i.e. Infrared. It can also see the baby Universe, the time when stars and galaxies had just started to form.

How far back in time can the James Webb Telescope see?

The James Webb Space Telescope will be able to see what the Universe looked like around more than 13.5 billion years ago.

In other words, JWST will be able to see back to about 100 million – 250 million years after the Big Bang.

Objectives of the James Webb Space Telescope

Imagining the Universe at its very beginning is still a dream for many, but the JWST can make it happen.


The JWST is supposed to collect data, and images that would help study the Early Universe – the origin, and evolution of galaxies, stars, and planetary systems.

There are many questions about the Universe that JWST is going to help evince, some of them being –

What are the first galaxies?

Since the JWST is able to detect the infrared wavelength, infrared radiation from the first galaxies in the early Universe could now be detected.

Capturing faint galaxies would help study the environment of the early Universe and the formation of the early galaxies.

When did the reionization occur?

After some time had passed in the early Universe, electrons, and protons from the hot plasma combined to form neutral atoms of majorly hydrogen and helium(this process is called recombination).

Again after some time, these neutral atoms reionized into hot plasma through the reionization process.

The JWST can help us understand the timeline and environment of the universe during the process.

How did the heavy elements form?

Initially, the Universe consisted majorly of hydrogen and some helium. As we know today, heavier elements like metals are formed due to the fusion processes and collisions of different kinds of stars.

It will be very interesting to learn how these heavy elements were formed when there were no stars or galaxies in the early Universe.


Studying stellar & extraterrestrial environments

Last but not least, the JWST would help us evince some of these foundational questions about the Universe and the existence of life.

We will be able to learn more about how stars, star systems, and planets were formed.

A big advantage of being able to detect infrared wavelength is that it can pass through dust and clouds.

This means JWST will also be able to peek into the formation of stars right through the massive clouds of dust which are opaque to visible light.

Studying the atmosphere of the exoplanets in more detail that are in the habitable zone of star systems and exploring the possibility of them harboring extraterrestrial life would be better possible for the JWST.

Structure of the James Webb Space Telescope

James Webb Space Telescope Blueprint
These blueprints of the James Webb Space Telescope were created as a prop for a video series. Credit: NASA

The James Webb Space Telescope is unlike any other telescope ever built with such a large primary mirror constructed by joining 18 hexagonal mirror segments made of Beryllium and coated with a thin layer of gold.

Webb is coated with gold due to its properties like a high reflection of infrared light and extreme unreactivity.

James Webb Telescope Weight, Dimensions & Specifications

The 6.25m large primary mirror of JWST will give a wider field of view than Hubble with a 2.4m diameter of its primary mirror.

It is said that JWST is 100 times more powerful than HST.

Webb’s sunshield is about 22 meters by 12 meters (69.5 ft x 46.5 ft). It’s about half as big as a 737 aircraft, the Sunshield is about the size of a tennis court.

Webbs weighs about 6500 kg and is lighter than the Hubble Space Telescope (weighs about 12,246 kg) despite being bigger than it.

Primary Mirror Size Comparison Between Webb and Hubble. Credit: NASA

There are four major instruments on the JWST that would be involved in the science operations:

  • Mid-Infrared Instrument (MIRI) – It has both a camera and a spectrograph that sees light in the mid-infrared region of the electromagnetic spectrum, with wavelengths that are longer than our eyes see.
  • Near-Infrared Camera (NIRCam) – It is the James Webb Telescope’s primary imager that will cover the infrared wavelength range of 0.6 to 5 microns.
  • Near-Infrared Spectrograph (NIRSpec) – It is a spectrograph (also sometimes called a spectrometer) is used to disperse light from an object into a spectrum which is used to analyze elements present in observed celestial bodies.
  • Near-Infrared Imager and Slitless Spectrograph/Fine Guidance Sensor – It allows Webb to point precisely so that it can obtain high-quality images.

The structure of JWST is a lot more complex than HST as infrared telescopes can work only in very low temperatures (as low as 5-7 Kelvins or -266 to -268°C).

These parameters introduced many engineering challenges to NASA, these were also a part of the reasons behind the delay in the JWST development and launch.

Challenges for the James Webb Space Telescope

The James Webb is the most expensive telescope ever built in human history.

James Webb Space Telescope Cost

The JWST is worth 10 billion in US Dollars.

Every component and technology used in manufacturing has been made entirely from scratch.

Very Expensive & Delicate Equipment

The mirror, cryogenic cooler, sun shield, and fine Guidance sensor are the most extensive in their respective category.  

With so much expense and being launched on Ariane 5, it was a nerve-wracking stretch for Scientists and Engineers and every other person who was hooked onto the program.

Any slight anomaly can waste this $10 Billion worth of telescope into dust

On 22nd November an incident occurred while connecting the telescope with the Ariane 5 upper-stage adapter.

The clamps which were holding the telescope started shaking due to an error.

This led to a delay in the launch of the telescope as engineers have to test the telescope again for any possible damage.

Although there wasn’t any damage seen on the telescope, this shows how delicate the instrument is.


One of the main challenges for the engineers was the full deployment of the sun shield.

It is like folding a parachute, and hoping for perfect parachute deployment while floating in the air.

If something goes wrong, it will be the last mistake

James Webb Space Telescope is Unserviceable

The first servicing mission to the Hubble Space Telescope saw astronauts install a set of specialized lenses to correct the flawed main mirror in the telescope. Credits: NASA

Unlike the Hubble Space Telescope, JWST is unserviceable, i.e. no one can go to the telescope and fix things up.

Hence it’s a very tough time for NASA to get the telescope to its place fully functional.

The mirror and instruments have almost no protection from the tiny meteorites that can anytime hit the JWST, though the probability is low, it’s not zero.

Even a sand-sized particle can render the telescope unfunctional.

Hence, it’s just a matter of luck for the JWST to survive for a long period.

With the telescope being placed far away from the Earth, there won’t be any possibility of providing manual help or service missions that the HST had if anything does go wrong.

Protecting the James Webb Space Telescope from heat & the Sun

As mentioned earlier, JWST is an infrared telescope, and such telescopes can only work in very low temperatures.


So it’s required to shield the space telescope from excessive heat and also from the direct radiation of the Sun.

To stay away from the radiation coming from Sun, Earth, and Moon altogether, NASA decided to place it behind Earth, 1.5 million kilometers away at the L2 point (Lagrange 2 point is one of the 5 points in the solar system where a satellite can stay at a relative position to Earth and Sun).

Position of the Lagrangian Point 2 (Lagrange Point 2)
Location of the halo orbit of the James Webb Space Telescope
Planned location of the Gaia spacecraftLissajous orbit
Credits: ESA
Animation of JWST’s orbit. JWST will not be exactly at the L2 point, but circle around it in a halo orbit. Credits: NASA

NASA has also equipped the JWST with a 5-layer sun shield which will span to the size of a tennis court when deployed.

The 5 layers help to reflect the light from the sun and reflect excess infrared radiation coming from Earth and Moon.

It will provide passive cooling to the Telescope. Only 0.2% of the Sun’s energy will reach the telescope and this will bring down the temperature to 37 Kelvin (-236°C). 

The mid-infrared telescope used in JWST is very sensitive to heat.

It needs to be cooled down below 7 Kelvin (-266°C) to work properly. For that, JWST houses a cryocooler as an active cooling system

Despite how ambitious the mission is, it has suffered countless challenges and delays in its way. 

LGBTQ Community: Rename James Webb

Challenges to JWST are not merely technical and physical, it encountered social challenges too.

The uproar against the name of the telescope was dragged into a controversy.

James Edwin Webb, the former administrator of NASA after whom the telescope has been named, was said to be involved in the persecution of the LGBTQ community from 1950 to the 1960s.

Many Scientists and Astronomers protested against it but NASA refused to change the name as there was no strong evidence in the favor of the dispute and they did not want the launch to get delayed further.

Timeline of the James Webb Space Telescope Project

JWST has undergone creation for quite a while. It was a collaborative effort of the National Aeronautics and Space Administration(NASA), the European Space Agency(ESA), and the Canadian Space Agency(CSA).

In 1996, its development commenced and was planned to launch in 2007.

James Webb had seen its fair share of delays and cost overruns over the past decades.


Note: During the 25 years of development of the JWST project, the worth of US dollars itself has been variable, so you might see some evaluation flaws in older articles regarding cost estimations of the JWST around the internet.

1996-1999, Initiation of the Next Generation Space Telescope (NGST)

The Next Generation Space Telescope Project was initiated in 1996, which could surpass the capabilities of the HST, and help humans study every phase in the history of our Universe.

Initial Budget Estimation: US$0.5 to 1 billion

Planned Launch date then: No earlier than 2007

2000, Cancellation of the NEXUS Space Telescope due to Lack of funding

NEXUS was supposed to be the precursor of the NGST, as an in-space technology risk reduction experiment, aimed to gather data in order to reduce the technical risks with future projects.

The NEXUS Space Telescope had an anticipated launch date of 2004 but got canceled in 2000, due to lack of funding.

Estimated Cost now: US$1.8 billion

2002, NGST became the James Webb Space Telescope (JWST)

The “Next Generation Space Telescope” (NGST) was renamed to James Webb Space Telescope (JWST) in Sept. 2002 after a former NASA administrator, James Webb.

Estimated Cost now: US$2.5 billion

2003, TRW gets awarded an $824.8 million contract with JWST

NASA selected TRW – a former American corporation involved in a variety of businesses, mainly aerospace, and automotive – for a US$824.8 million (US$824.8 million as of 2003) contract, to build a next-generation successor to the Hubble Space Telescope, the James Webb Space Telescope.

Planned Launch date now: No sooner than 2010

Estimated Cost now: US$2.5 billion

2010, JWST Passed the Mission Critical Design Review

In April 2010, JWST passed the technical part of its Mission Critical Design Review (MCDR).

Passing this meant the integrated observatory can meet all science and engineering requirements for its mission.

Estimated Cost now: US$6.5 billion

2011, Proposed NASA Budget Bill Would Cancel JWST

In July 2011, the United States House of Representatives appropriations committee on Commerce, Justice, and Science voted to cancel the James Webb project’s overall budget due to the deduction of $1.6 billion from NASA’s overall budget in FY2012.

It generated a wave of support from the American Astronomical Society and the International press in 2011. 

Estimated Cost now: US$8.7 billion

2011, NASA successfully mitigates the James Webb Space Telescope cancellation

In November of 2011, congress “reinstated” the project with a fund cap of $8 billion and NASA delayed its other projects to keep JWST going.


Construction of the integrated space observatory was initiated after it passed all the Technical and design reviews.

Estimated Cost now: US$8 billion

2014, JWST Funding hit $650 million

The James Webb Space Telescope was continually facing manufacturing problems and hit US$650 million(US$650 million as of 2014) worth of funding from the U.S.

2015, Contract signed for JWST Launcher

ESA signed a contract with Arianespace, that will prepare an Ariane 5 rocket on which the James Webb Space Telescope will be launched, on the next decided date from Europe’s Spaceport in Kourou in October 2018.

Planned launch date now: No earlier than October 2018.

2016, JWST Construction Completed & entered the testing phase

In 2016 it was finally got completed and NASA began testing this week on the 21ft arrangement of mirrors and instruments of the James Webb Space Telescope.

James Webb Telescope Previous Launch Dates & Delays

2018, the JWST Launch date delayed to 2020

NASA reported technical issues on JWST over the last year, delaying the timeline for the telescope’s launch, including problems with a transducer in the propulsion system, which led to other issues that required fixing.

Planned Launch date now: No earlier than May 2020.

2018, JWST Launch postponed to 2021

On 27th July 2018, Jim Bridenstine, former NASA Administrator, tweeted –

“The James Webb Space Telescope will produce first-of-its-kind, world-class science. Based on recommendations by an Independent Review Board, the new launch date for NASAWebb (James Webb Space Telescope) is March 30, 2021. I’m looking forward to the launch of this historic mission.”

Planned Launch date now: No sooner than 30th March 2021.

Cost Estimate now: around US$8.8 billion

2020, JWST Launch was postponed again

Due to the impacts of the Covid 19 pandemic, on 16th July 2020, the launch postpone was proceeded up to 7 months further than the previous target.

Planned Launch date now: No sooner than 31st October 2021.

Cost Estimation now: US$9.66 billion(as of March 2019)

Consecutive Delays in 2021

  • On June 1, 2021, the JWST launch was postponed again, to no earlier than November 2021 due to concerns regarding the readiness of the Ariane 5 launch vehicle and launch site.
  • On 8th September, after consultation with Ariane Space Agency, NASA postponed the JWST launch date to December 18, 2021, due to some shipment and spacecraft wrap-up operations.
  • November 22, JWST launch was delayed to no earlier than December 22, 2021, to allow additional testing after experiencing vibrations due to an unplanned clamp release after an accident in the launch facility.
  • On December 15, 2021, the JWST launch was delayed again to no earlier than December 24, 2021, due to an electrical fault. A communications error between the base and the telescope.
  • December 21, 2021, the JWST launch was delayed yet again to no earlier than December 25, 2021, due to adverse weather conditions at the launch site.

Estimated Cost now: US$9.7 billion(as of December 2021)

James Webb Space Telescope Launch Date – 25th December 2021

On 21st December 2021, NASA declared the launch date to be 25th December 2021 with the help of Ariane flight VA256.

And thus, the James Webb Space Telescope after enduring all these complications was finally launched on 25 Dec 2021.

December 25, 2021, Liftoff at 12:20 UTC.

The telescope was also confirmed to be receiving power and is traveling to its target destination, as of January 2022.

NASA’s lifetime cost for the project is expected US$9.7 billion(~ US$10 billion), of which US$8.8 billion was spent on spacecraft design and development, and US$861 million is planned to support five years of mission operations.

When will the James Webb Space Telescope start working?

James Webb Space Telescope Deployment Sequence (Nominal). Credits: NASA

It will take roughly 30 days for Webb to reach the start of its orbit at L2, but it will take only 3 days to get as far away as the Moon’s orbit, which is about a quarter of the way there.

After the launch day, during the upcoming 6 months, the JWST will go through its different deployment and warm-up operations.


In the first week, the JWST’s sunshield deployment will be executed.

In the first month, Telescope deployment, cooldown, instrument turn-on, and insertion into orbit around L2 will be executed.

In the second, third, and fourth months, Initial optics checkouts and telescope alignment would take place.

Calibration and completion of commissioning would be completed in the fifth and sixth months.

So we can say, after about six months taking from the 25th of December, the James Webb Space Telescope will finally start its science mission and begin conducting routine science operations.

Latest James Webb Space Telescope Updates:

  • The JWST launch was successfully executed on the 25th of December 2021.
  • On 2022 January 4, NASA announced the successful deployment of the JWST Sunshield ten days after the launch.
  • James Webb Space Telescope has completed the two-week-long deployment procedure as of 9th January 2021, that’s 50 major deployments after the latching of Webb’s last mirror wing.
  • The JWST has finally reached its orbit, the second Lagrange Point (L2). It will orbit the Sun, in line with Earth, as it orbits the L2.

The First image by James Webb Space Telescope – Aligning the mirrors

This image mosaic was created by pointing the telescope at a bright, isolated star in the constellation Ursa Major known as HD 84406. This star was chosen specifically because it is easily identifiable and not crowded by other stars of similar brightness, which helps to reduce background confusion. Each dot within the mosaic is labeled by the corresponding primary mirror segment that captured it. These initial results closely match expectations and simulations. Credit: NASA

The James Webb Space Telescope is close to the completion of the first phase, which is a months-long process of aligning the observatory’s primary mirror using the Near Infrared Camera (NIRCam) instrument.

The challenge is to confirm if NIRCam was ready to collect light from celestial objects, and then identify starlight from the same star in each of the 18 primary mirror segments.

The result is an image mosaic of 18 randomly organized dots of starlight, the product of Webb’s unaligned mirror segments all reflecting light from the same star back at Webb’s secondary mirror and into NIRCam’s detectors.

This simple image of blurry starlight is the foundation to align and focus the telescope in order for Webb to capture entirely new and unique views of the universe.

Over the next month or so, the team will gradually adjust the mirror segments until the 18 images become a single star.

Voyage of Humanity Into the Origins of the Universe

Despite all of the challenges and hurdles, the James Webb Telescope faced, it is now finally set on its voyage to the origin of humanity.

It will unfold the deep secrets of the Universe and help humanity find the answers to some of the most important and fascinating questions –

“How did the early Universe look like?” and perhaps also “Are we really alone in this vast Universe?”


The successful JWST launch on 25th December 2021 was indeed the best Christmas gift for all Scientists and Engineers across the world.

Will it be worth the intense effort and resources that were poured into it? is a question about time.

But there are many asked and unasked questions that are yet to be answered, folks.

We’ll be reporting the findings of NASA’s all-new hope for Astronomic exploration in yet other flashy articles. So stay tuned with us!

Let’s hope for the best and keep unraveling the depths of reality.


  • Amended planned launch dates & budget table – Wiki
  • Latest Updates of James Webb Space Telescope by NASA
  • James Webb Space Telescope Launch tribute by NASA
  • James Webb was formerly known as NGST – Web Archives
  • How far back in time can James Webb Telescope see? – NASA
  • Cancellation of NEXUS predecessor of JWST – MIT
  • Hubble Space Telescope – NASA
  • Chandra X-ray Observatory – CXC Havard
  • The Dark Age of the Universe – Wiki
  • Photons Received: Webb Sees Its First Star – NASA


Allen Isaac, Pranav Mahapatra