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James Webb Space Telescope: Origins, design and mission objectives

An illustration of the James Webb Space Telescope

An artists impression of the way the James Webb Space Telescope can look after deployment.(Image credit: ESA)

The James Webb Space Telescope (JWST), which launched Dec. 25, 2021 at 7: 20 a.m. ET (12: 20 p.m. GMT) from the Guiana Space Centre (also referred to as Europe’s Spaceport) in French Guiana, is on a mission to see a few of the faintest, oldest objects in the universe, from the vantage point nearly 1 million miles (1.5 million kilometers) from Earth.

On July 11, President Joe Biden shared the first full-color image captured by JWST, which astronomers hailed because the deepest image of the universe ever taken. The very next day, NASA released four more debut images to showcase Webb’s incredible capabilities, including close-ups of a distant dying star, an alien exoplanet and a cluster of five galaxies chaotically colliding.

Webb includes a lot to call home up to because the successor of the Hubble Space Telescope, a still-active space observatory capturing spectacular images of the cosmos. In the three decades since Hubble launched in 1990, it has revealed the wonders of the universe in unprecedented detail. It has been used to review cutting-edge topics like dark energy and exoplanets which were scarcely imagined when it began operation. Plus, it has captured the public’s imagination to the extent that it’s now children name.

The James Webb Space Telescope, referred to as Webb (like “Hubble”), is operated primarily by NASA, that is providing the majority of the funding, with the European Space Agency (ESA) and the Canadian Space Agency (CSA) as partners. The telescope is known as after among NASA’s early administrators, James E. Webb, who oversaw the creation of the Apollo program in the 1960s, in accordance with NASA (opens in new tab).

It had been in the past in 2002, almost 20 years back, when Webb’s name was initially put on what had previously been known as the “Next Generation Space Telescope.” That decision was later called into question as JWST’s launch neared, with many scientists arguing that Webb participated in discrimination against lgbt NASA employees during his time being an administrator for the agency, and for that reason shouldn’t have his name affixed to the high-profile observatory, in accordance with Live Science sister site (opens in new tab). (NASA announced in September 2021 they wouldn’t normally rename the mission, reported.)

On Dec. 25, 2021, Arianespace's Ariane 5 rocket launches with NASA's James Webb Space Telescope onboard, from the ELA-3 Launch Zone of Europes Spaceport at the Guiana Space Centre at Europes Spaceport, at the Guiana Space Center in French Guiana.

On Dec. 25, 2021, Arianespace’s Ariane 5 rocket launches with NASA’s James Webb Space Telescope onboard, from the ELA-3 Launch Zone of Europes Spaceport at the Guiana Space Centre at Europes Spaceport, at the Guiana Space Center in French Guiana. (Image credit: Bill Ingalls/NASA via Getty Images)

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Webb was originally planned to cost half of a billion dollars and become ready for launch in 2007, the Atlantic (opens in new tab) reported.However, these estimates ended up being over-optimistic, given the enormously complex and innovative design of the spacecraft. Building the telescope cost nearly $10 billion, almost doubling the estimated cost since 2009, based on the U.S. Government Accountability Office. (opens in new tab).

Nevertheless, the scientists mixed up in project believe the outcomes will a lot more than compensate for enough time and money committed to it. NASA is keen to emphasize that Webb isn’t just a bigger and much more powerful telescope than Hubble. Although it is both those ideas with an increase of than two . 5 times the diameter and 100 times the sensitivity at its heart the JWST is really a different kind of instrument altogether.

Related: How are asteroids and space debris detected before they hit Earth?

Ordinary optical telescopes see in exactly the same portion of the spectrum as our very own eyes, covering a variety of wavelengths between roughly 380 and 740 nanometers (nm), as Live Science has previously reported. Hubble spanned all this, and also a little way in to the ultraviolet at shorter wavelengths and infrared at longer ones.

However the JWST will primarily be an infrared telescope, optimized for 600 to 28,000 nm, in accordance with NASA’s JWST website (opens in new tab). So that it won’t be in a position to see green or blue light, just orange and red and also a wide variety of longer wavelengths beyond that.

A portrait of James Webb

James Webb, after whom the telescope is known as, was NASA administrator in the 1960s. (Image credit: NASA)

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For most astronomical objects, including star-forming regions, exoplanets and probably the most distant galaxies, these lengthy wavelengths tend to be more beneficial to astronomers compared to the visible spectrum. But infrared poses problems for Earth-based telescopes, because a lot of it really is blocked by our planet’s atmosphere, based on the University of St Andrews (opens in new tab).

In addition, the planet earth produces its infrared emissions via heat radiation, which have a tendency to swamp the fainter astronomical sources. Therefore the best place for an infrared telescope has gone out in space, so far as possible from the planet earth and all its unwanted resources of heat.

Related: Just how many satellites orbit Earth?

Following in the footsteps of ESA’s Herschel infrared observatory, the Webb telescope will undoubtedly be located nearly 1 million miles (1.5 million kilometers) from Earth at the so-called L2 point, in accordance with NASA’s JWST website.

This can give Webb a much clearer view of the universe compared to the one Hubble has in low-Earth orbit, nonetheless it has a downside. Unlike its predecessor, Webb isn’t easily reachable by way of a repair team of astronauts if it reduces. Everything must work perfectly on the initial attempt, that is among the explanations why it’s taken NASA the very best part of 2 decades to obtain Webb ready for launch.

Webb’s first images

President Joe Biden revealed JWST’s first full-color image on July 11. Named “Webb’s first deep field,” the image shows a cluster of galaxies called SMACS 0723, located about 4.6 billion light-years from Earth. Astronomers targeted this cluster due to its extraordinary mass; the galaxy cluster is indeed massive that it bends and magnifies the light of distant galaxies located behind it, allowing us Earthlings to peer deep in to the cosmic past.

Through this light-bending process, referred to as gravitational lensing, SMACS 0723 is seen magnifying the light of a few of the earliest galaxies in the universe, located some 13.5 billion light-years from Earth. Those galaxies appear as warped, swooping arcs of light round the central galaxy cluster. Astronomers have previously detected at the very least two galaxies in this image which are candidates for the oldest galaxy ever observed.

NASA’s James Webb Space Telescope has produced the deepest and sharpest infrared image of the distant universe to date. Known as Webb’s First Deep Field, this image of galaxy cluster SMACS 0723 is overflowing with detail.

NASAs James Webb Space Telescope has produced the deepest and sharpest infrared image of the distant universe up to now. Referred to as Webbs First Deep Field, this image of galaxy cluster SMACS 0723 is filled with detail. (Image credit: NASA, ESA, CSA, and STScI)

On July 12, NASA revealed four more debut images from the JWST. These included a spectrum image of a nearby alien exoplanet, which reveals the complete chemical composition of the planet’s atmosphere, and many dazzling close-ups of enormous, dust-shrouded objects located through the entire universe.

Possibly the most iconic early image is JWST’s closeup of the Carina Nebula, a bright and gassy hotbed of star formation located approximately 7,600 light-years from Earth. Scientists have studied this nebula extensively, however the new image reveals the “cosmic cliffs” of Carina in more stunning detail than previously. A huge selection of newborn stars, previously invisible to telescopes, shine through the entire gassy landscape of the nebula. Jets and eddies of dust swirl through the image, creating strange structures that scientists can’t even identify, in accordance with NASA.

This landscape of

This landscape of “mountains” and “valleys” speckled with glittering stars is in fact the edge of a nearby, young, star-forming region called NGC 3324 in the Carina Nebula. Captured in infrared light by NASAs new James Webb Space Telescope, this image reveals for the very first time previously invisible regions of star birth. (Image credit: NASA, ESA, CSA, and STScI)

Another popular image shows the Southern Ring Nebula, or “Eight-Burst Nebula” a figure-eight-shaped cloud of gas and dust expelled by way of a massive, dying star some 2,500 light-years from Earth. The spectacular image shows a glowing orange foam of molecular hydrogen swirling around a blue haze of ionizedgas, bursting out of doomed star at the image’s center.

Two cameras aboard Webb captured the latest image of this planetary nebula, cataloged as NGC 3132, and known informally as the Southern Ring Nebula. It is approximately 2,500 light-years away.

Two cameras aboard Webb captured the most recent image of the planetary nebula, cataloged as NGC 3132, and known informally because the Southern Ring Nebula. It really is approximately 2,500 light-years away. (Image credit: NASA, ESA, CSA, and STScI)

Where does JWST ‘live’ in space?

An integral feature of Webb’s design is that it includes a “cold side” and a “hot side.” The cold side may be the one which does the observing, as the hot side carries the spacecraft’s solar power panels and an antenna for two-way communication with Earth. But this arrangement only works if sunlight and Earth are always facing in exactly the same direction from the spacecraft’s perspective.

This wouldn’t function as case if Webb were simply put into Earth orbit like Hubble, nor would it not be true if the spacecraft orbited sunlight at a slightly different distance from the Earth’s orbit. Nonetheless it turns out there’s one special distance of which an object can orbit sunlight and always start to see the Sun and Earth in exactly the same direction. This is actually the so-called L2 point and it’s really where in fact the Webb telescope will operate.

L2 is among five locations in space called Lagrange points, after Joseph-Louis Lagrange who studied them in the 18th century. At these locations the gravity of two massive bodies (in cases like this sunlight and Earth) conspire to help keep a third, smaller body (such as for example an asteroid or spacecraft) in a set position in accordance with the initial two. The Lagrange points aren’t stationary, however they revolve round the Sun at a similar rate because the Earth, therefore the distance from us always stays exactly the same. Regarding L2, it’s around 1 million miles (1.5 million kilometers) away: around four times as a long way away because the moon.

To have the telescope completely to L2 required a robust launch vehicle: the ESA’s Ariane 5 rocket. In only 26 minutes following lift-off from French Guiana, this carried Webb free from Earth’s atmosphere and wear it course for L2. The spacecraft then separated from the rocket and cruised for about per month, making small adjustments to its trajectory before finally coming to L2 on Jan. 24, Live Science previously reported.

So how exactly does the Webb telescope work?

Externally, the JWST looks completely different from Hubble. The latter, as being a traditional telescope, is enclosed in a cylindrical tube that shields the optics from stray light. Based on its position in its orbit, Hubble could be exposed to plenty of light: blazing sunshine in one direction, reflections from the Earth’s surface in another, or even the moon.

But Webb is more fortunate. Seen from the L2 point each one of these bright sources come in pretty much exactly the same direction, so all of the telescope needs is really a single large sunshield. The bare optics, by means of primary and secondary mirrors, then take a seat on top of the. The result, initially, looks similar to a radio telescope than an optical one.

Functionally, however, both Webb and Hubble are constructed on a single principles. They’re both built around a big primary mirror, which includes the key job of capturing just as much light as you possibly can from objects which may be on the edge of the observable universe. Essentially, the larger this mirror is, the higher.

In Hubble’s case it’s 8 feet (2.4 meters) in diameter, and created from an individual circular little bit of glass. If this is scaled around the size necessary for the JWST around 21.3 feet (6.5 meters) across then not merely would it not be extremely difficult to fabricate, however the result will be too big and heavy to launch into space, in accordance with NASA.

JWST primary mirror

The huge primary mirror of the JWST during ground testing by NASA engineers. (Image credit: NASA)

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Instead, Webb’s mirror is made of 18 hexagonal segments, that have been folded up for launch and deployed into an operational configuration once in space. Although NASA considered making the segments from glass, like Hubble’s mirror, ultimately they used beryllium: an extremely strong, lightweight metal commonly used in high-speed aircraft and space vehicles.

This must be shaped and polished to extremely high accuracy to be able to produce images with the required clarity; NASA estimates the polishing error to be significantly less than a millionth of an inch. After reaching the desired shape, the mirror segments were then coated with a thin layer of pure gold, to increase reflectivity at infrared wavelengths.

When all of the segments are placed together, they achieve the required 21.3-foot (6.5-meter) diameter for the primary mirror. That’s around 2.7 times as large as Hubble’s, however the actual performance improvement is a lot higher than this.

That’s as the light-collecting power of a mirror is proportional to its area instead of its diameter. Enabling the hexagonal form of the segments and the hole in the guts, the effective section of Webb’s mirror is 269 square feet (25 square meters), weighed against 43 square feet (4 square meters) for Hubble. That compatible a performance improvement of much better than one factor of six.

Related: Cosmology: Uncovering the story of the universe

JWSTs sunshield

Located at the L2 point, the JWST will sit in constant bright sunshine. That is healthy for the gear in the spacecraft bus, but bad news for the optical instruments and science module. Since they observe via infrared, these have to be kept as cold as you possibly can to be able to function correctly.

Therefore the two halves of the spacecraft will undoubtedly be separated by way of a huge, kite-shaped, five-layer sunshield roughly how big is a tennis court. As the sunlit side may reach temperatures of 212 degrees Fahrenheit (100 degrees Celsius), the cold side will undoubtedly be only minus 394 F (minus 237 C) in accordance with NASA’s JWST website.

All five layers of the sunshield were successfully deployed on Jan. 24, reported (opens in new tab).

The JWST sunshield

The Sunshield on NASA’s James Webb Space Telescope. (Image credit: NASA/Chris Gunn)

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Why do JWT’S optical instruments observe in infrared?

We normally think about astronomy when it comes to visible light, because that’s what our eyes and traditional telescopes see. But astronomical objects produce emissions over the whole of the electromagnetic spectrum, from lengthy wavelength radio waves to very short wavelength X-rays and gamma rays. Our eyes evolved to start to see the wavelengths they do because that is where sunlight emits the majority of its energy, but cooler objects, such as for example planets and newly formed stars, have a tendency to radiate at longer wavelengths than this, in accordance with research published in 2021 in the journal Eye (opens in new tab).

That is one reason infrared telescopes such as for example Webb (and its own predecessor, NASA’s Spitzer space telescope, which operated between 2003 and 2020) are so important. Another reason is that as the dust in galaxies absorbs visible light, it’s virtually transparent to infrared waves. This implies even sun-like stars could be simpler to see in the infrared if there’s lots of intervening dust, in accordance with NASA.

On Feb. 2, NASA engineers began conducting the initial imaging tests with Webb, with the 18 mirror segments capturing images of stars that could then be utilized to align the principal mirror, so the 18 individual images eventually merge to become single star, NASA reported (opens in new tab).

Do you know the mission objectives of JWST?

Objective 1: The first universe

Webb may also be referred to as a “time machine,” which in a way it really is. Because light from distant objects travels at finite speed, we see them because they was previously previously. Hubble shows us galaxies because they were many vast amounts of years ago, however the JWST will undoubtedly be a lot more sensitive. NASA hopes it’ll see completely back to once the first galaxies formed, around 13.6 billion years back.

And Webb has another advantage over visible-band telescopes like Hubble.

As the universe is expanding, light from distant objects is extended, increasing its wavelength. This implies light emitted in the visible waveband actually reaches us in the infrared, the band that the JWST is optimized for. Among its first tasks is a survey, called COSMOS-Webb, of the very most distant galaxies in a particular patch of sky, to explore conditions at the dawn of the universe.

The COSMOS-Webb survey

The COSMOS-Webb survey will explore a location equal to three full moons. (Image credit: NASA)

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Objective 2: Galaxies as time passes

Because of Hubble’s spectacular imagery, a lot of people know very well what galaxies appear to be: huge collections of stars, often arranged in elegantly symmetric spiral patterns. But these are generally relatively nearby galaxies, and therefore mature ones. The tantalizing glimpses Hubble has provided of very early galaxies suggests they’re considerably smaller and messier-looking.

Up to now, no-one knows how these proto-galaxies formed, or how they subsequently clumped together to create the bigger, regular-looking galaxies we see today, based on the California Institute of Technology (opens in new tab). It’s hoped that Webb can answer questions like these using its ultra-deep view of the first universe.

Another well-established feature of galaxies may be the presence of supermassive black holes in the centers of all of these. In the first universe, these black holes often powered enormously bright galactic nuclei called quasars, and Webb is scheduled to review six of the very most distant and luminous types of these.

An artist's impression of a quasar

A NASA artists rendering of a robust quasar of the sort Webb will study. (Image credit: NASA)

Objective 3: Lifecycle of stars

The galaxies that fill the universe originated very in early stages, and they’ve steadily evolved since then. But that isn’t true of the stars included, which proceed through life cycles more comparable to living creatures. They’re born, develop, age and die, and the remnants of old stars donate to the raw material had a need to make new stars. A lot of this technique is well understood, but there’s still a mystery surrounding the specific birth of stars, and the planetary discs that could form around them.

That’s because baby stars are initially enveloped in the cocoon of dust, which ordinary telescopes using visible light can’t penetrate. But all of this dust will undoubtedly be virtually transparent at the infrared wavelengths utilized by Webb, so NASA hopes (opens in new tab) it’ll finally reveal the best secrets of star formation. Subsequently, this might teach us something concerning the origins of our very own sun and solar system.

Objective 4: Other worlds

Probably the most exciting regions of contemporary astronomy may be the seek out exoplanets orbiting other stars, particularly Earth-like planets that could have the chemical ingredients and conditions essential for life to evolve. The JWST will donate to this search in a number of ways, using infrared imaging and spectroscopy to review the chemical and physical properties of planetary systems.

Its capability to peer through dust and snap super-high resolution images should provide us with a primary view of planetary systems such as for example that of the newly formed star Beta Pictoris within their very earliest stages, in accordance with NASA’s JWST website. Webb may also analyze the chemical composition of exoplanet atmospheres, looking specifically for tell-tale signatures of the inspiration of life. This again is something an infrared telescope is ideally fitted to, as the molecules creating planetary atmospheres are generally most active at these wavelengths.

Hubble’s view of Beta Pictoris

Hubbles view of the planetary disc around Beta Pictoris, that your JWST will study in greater depth. (Image credit: NASA)

Q&A having an Astrophysicist

We asked NASA’s Dr Mike McElwain about his hopes for the brand new telescope.

Headshot of Mike McElwain

Michael McElwain is JWST Observatory Project Scientist at NASAs Goddard Space Flight Centre. (Image credit: NASA/Jolearra Tshiteya)

What type of science will the telescope do in its first year?

In the initial year, Webb’s observing program will run the cosmic gamut: from the initial light in the first universe to exoplanet atmospheres. Webb will take notice of the best objects in the universe with a variety of improved resolution, sensitivity and wavelength coverage. This can enable new and enhanced characterization of the famous objects in the sky. When you can name it, Webb will probably observe it, though not all in the initial year.

Do you know the most exciting discoveries the JWST will make?

If you have an observatory as transformational as Webb, probably the most exciting discoveries will tend to be those that we dont even anticipate! Webbs infrared eyes on the universe will enable us to see space where we were previously blind. Its unprecedented infrared sensitivity can help astronomers compare the initial galaxies to today’s grand spirals and ellipticals, helping us to comprehend how galaxies assemble over vast amounts of years. It’ll be in a position to see through and into massive clouds of dust which are opaque to visible-light observatories like Hubble, where stars and planetary systems are increasingly being born. Webb will reveal more concerning the atmospheres of extrasolar planets, as well as perhaps even discover the blocks of life elsewhere in the universe.

Do you consider Webb can be children name like Hubble?

I fully expect it’ll, and that folks around the world will undoubtedly be discussing Webb imagery while sitting round the dinner table. Much like Hubble, Webb will produce spectacular images of the cosmos which will captivate the imagination. We expect Webb imagery to go viral on the web, arrive in calendars and occupy space on household coffee tables.

Editor’s Note: This short article was updated to reflect new James Webb discoveries on July 29, 2022.

Additional resources

  • Want a crash-course on the Webb Telescope? Have a look at James Webb Space Telescope: A Super-Quick Guide (opens in new tab) on Kindle, for an easy introduction to the pioneering observatory.
  • If you love a deeper dive, it is possible to find out about the Webb mission from the European Space Agency (opens in new tab) (ESA).
  • For spectacular images of Webb and its own partner in space, Hubble visit this ESA gallery (opens in new tab).
Andrew May

Andrew May holds a Ph.D. in astrophysics from Manchester University, U.K. For 30 years, he worked in the academic, government and private sectors, before learning to be a science writer where he’s got written for Fortean Times, HOW IT OPERATES, ABOUT Space, BBC Science Focus, amongst others. He’s got also written an array of books including Cosmic Impact and Astrobiology: The Seek out Life Elsewhere in the Universe, published by Icon Books.

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