5 Mind Boggling facts on the James Webb Space Telescope

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Popularly dubbed as the prodigal replacement to the ageing Hubble Space Telescope, here are 5 mind-blowing ultra-cool facts about the James Webb Space Telescope or in short the JWST.

This space telescope has many firsts to its credit.

  1. largest of all space telescopes launched by man
  2. relies on Infrared to peer into the Universe
  3. works at temperatures close to 0 degrees Kelvin
  4. designed to self deploy in space
  5. primary mirrors made of beryllium-gold combination

However, the following 5 facts are sure to blow your mind away

Fact #1 – A 10 billion USD telescope to study our 13 billion-year-old Universe

The JWST is an extremely costly piece of equipment. NASA is paying a tab of $10 billion dollars to cover the cost of building the one-of-its-kind JWST and ensure that it comes out perfectly the first time. There are two major reasons here

One of its kind

NASA has placed an order for only 1 JWST to be built. It is a custom made piece just on the lines of how NASA has ordered it. Hence all the expenses including research innovation and manufacturing are borne by this one piece only. Every company that has contributed to building this telescope will have to recover their cost through this one order only.

Complex Engineering

While the huge cost is partly due to the order of just 1 piece of it, the cost is also because of the extreme engineering that has gone into it.

For starters, every contingency or possible failure scenario has to be taken into account as there is no possibility of going after it or getting it repaired in space. With Hubble Space Telescope (HST), International Space Station (ISS) scientists routinely carried out repair and up-gradation work on it.

The JWST has to unfold itself in space, get assembled remotely to a precision of a millionth of an inch and keep itself close to 0 degrees Kelvin while operating in the punishing environs of outer space. All this requires pushing our manufacturing abilities to an extreme limit.

That’s how the costs add up.

Fact #2 – As big as a tennis court

The JWST is huge in size. As big as a tennis court to be exact.

The JWST measure 22 metres x 12 metres in dimensions when fully deployed. Though it weighs just 6 tonnes, (half of the HST), it occupies a considerably larger space. This unique requirement arises from its design philosophy.

JWST - As big as a tennis court
JWST – As big as a tennis court

The unique size of the JWST required NASA to innovate on how to keep it folded and compact so as to fit into the nose cone of the Arianne 5 Rocket that delivered it to space.

Over the next 6 months, the JWST will be remotely unfurled and assembled using the help of small motors on board to get it into its operational design.

Fact #3 – Located at a point that offers it 3 advantages

The James Webb Space Telescope will be parked at a special point in space called the Lagrange 2 (L2) point. This special point offers 3 unique advantages to the telescope whose very mission is to peer as deep as possible for as long as possible into the Universe.

JWST will be parked 1.5 million km from Earth

This point is 1.5 million km from Earth away from the Sun. This is nearly 4 times the distance from Earth to the Moon.

Unimpeded view of universe

As seen in the image, the L2 point is outside the Earth’s orbit away from the Sun. This puts both the Sun and the Earth behind the JWST at all times giving it an unparalleled and unimpeded view into outer space.

Lagrange Points for the Sun and the Earth

Cool Spot

The JWST is an infrared (IR) based telescope. It simply means that the telescope does not rely on visible light, but heat waves to look at things.

IR rays can penetrate thick clouds of gas and dust and travel farther without too much loss. This allows JWST to gather more information than possible using visible spectrum light.

To be in a position to detect the faintest of IR rays coming in from the depths of space, the telescope itself must cool itself to avoid mixing up deep space IR rays with IR rays of its own.

Portions of JWST will be cooled to within 7 degrees of 0 degrees Kelvin

Extended Mission period due to L2 location

The 3rd advantage of the L2 position comes from the negation of gravitational tug and centripetal force of the object at that point.

At Lagrange points, the gravitational pull of two large masses precisely equals the centripetal force required for a small object to move with them. These points in space can be used by spacecraft to reduce the fuel consumption needed to remain in position.

Fact #4 – Lighter, more powerful than Hubble

The James Webb Space Telescope is lighter than Hubble Space Telescope by a good 50%. The HST weighs around 12 tonnes while the JWST weighs just half at around 6.5 tonnes.

JWST versus HST - Comparision of their mirror apertures
JWST versus HST – Comparision of their mirror apertures

JWST is also 100 times more powerful than HST. With a mirror aperture having a diameter of 21.3 feet, it can capture more light than HST which has an aperture of 7.8 feet.

In fact, this aperture size combined with the fact that it captures images in Infrared allows it to see farther into the Universe.

Fact #5 – JWST can time-travel

With its ability to peer really deep, we can peel off the layers of time way back to nearly 13 billion years ago. JWST can capture infrared waves that have been travelling through space for almost as long as the Universe came into existence. This gives it the ability to literally look back in time to when the first ‘baby galaxies’ were forming after the Big Bang.


Assuming the deployment goes on as planned over the next 6 months since its launch on 22nd December 2021, we should be treated to spectacular images of our early universe. These can shed light on how the first galaxies were formed. Another mission of the telescope is to also peer into the dusty clouds of our Universe and look at just forming solar systems and possibly look at how life gets a foothold in the vast expanses of the Universe.

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