Hubble vs James Webb Space: Two Telescopes Compared

Hubble telescope in space

Hubble vs James Webb Space: Two Telescopes Compared

Hubble vs James Webb: 5 Must-Know Facts

  • The Hubble Space Telescope was the first optical telescope to orbit the Earth.
  • James Webb’s primary mirror is nearly three times the size of the Hubble.
  • Hubble’s original life expectancy was 15 years. It is currently going on its 32nd active year.
  • The James Webb Space Telescope doesn’t orbit the Earth, but actually, the Sun. the telescope is stationed at L2, a million miles away.
  • Webb’s infrared technology allows it to see farther into the universe’s origins and through space dust.

On July 21, 1969, Niel Armstrong took his first step on the moon and spoke these immortal words: “That’s one small step for man, one giant leap for mankind.” These words ignited enthusiasm around the world for space exploration.

Decades later, another phenomenon would overtake this historic moment. The Hubble Space Telescope and its fantastic imagery of the cosmos gave our dreams photographic proof of what is really out there.

With the Hubble at the end of its lifecycle, however, the James Webb Space Telescope is set to continue its legacy. Continue reading to learn more about the differences between Hubble vs James Webb.

Side by Side Comparison: Hubble vs James Webb

HubbleJames Webb
Associated organizationsNASA, ESA, STScINASA, ESA, CSA, STScI
ManufacturerLockheed, Perkin-ElmerNorthrop Grumman, Ball Aerospace
Launch dateApril 1990December 2021
RocketSpace Shuttle DiscoveryAriane 5
Mass24,490 lbs14,300 lbs
Size43 ft x 14 ft66 ft x 46 ft (sunshield)
Location in spaceGeocentric (LEO)Sun-Earth L2
Primary lens diameter8 ft21 ft
Focal length189 ft431 ft
WavelengthsVisible light, ultraviolet, near-infraredNear-infrared, mid-infrared
Cost$16 billion (ongoing)$10 billion

Hubble vs James Webb: What’s the Difference?

scientists and engineers assembling James Web Telescope
Engineers preparing James Webb Telescope for space launch.



Interest in an orbital telescope began before NASA was established. The astronomer Lyman Spitzer offered the benefits of studying the stars from space in 1946, proposing what was initially called the Large Space Telescope.

It took over three decades before the project was greenlighted, with funding for the Hubble Space Telescope awarded in 1977. This would finally allow researchers to study astronomy without the interference of Earth’s dense atmosphere.

Development of the telescope went steadily, and in 1990, it was ready for launch. Just 13 years after the start of the project, Hubble launched on the Space Shuttle Discovery. The telescope orbits around the earth and is within maintenance reach.

The year before Hubble launched, the Space Telescope Science Institute (STScI) started planning the next big instrument. Originally named the Next Generation Space Telescope, the institute proposed a project 5 times as large as Hubble with infrared capabilities.

The idea was that with the Universe rapidly expanding, only infrared technology could view it as the wavelengths expanded.

The project was greenlighted in 1997 following years of feasibility research; with a large primary mirror, how could they launch it? NASA elected to go with a folding, segmented mirror, the first of its kind. With state-of-the-art proposals, the telescope (renamed James Webb Space Telescope in 2002) would inch forward to completion.

It took 7 more years and $4 billion more in spending, but the Webb was finally launched on December 25, 2021, on the Ariane 5 European rocket. 


The Hubble’s location in geocentric orbit was critical, as the telescope needed adjustments immediately following its launch. Despite its 15-year life expectancy, researchers discovered that the primary mirror was a fraction of the width of a human hair, too flat.

Engineers had to develop corrective optics for the mirror, which was irreplaceable. This became one of the first five servicing missions to the telescope that would help extend its life.

The effects of these upgrades did miracles for the instrument. Designed with modular components, the Hubble was upgraded between 1993 and 2009. With the end of the Space Shuttle program in 2011, astronauts could no longer return to repair it, but the telescope was already living longer than intended.

The Hubble Space Telescope is still active, 32 years after its launch. Scientists plan to decommission the telescope in 2026.

Unlike the Hubble, James Webb’s delicate, infrared instruments needed to be well clear of Earth’s atmosphere. It was launched toward the second Lagrange point (L2) a million miles from the planet, orbiting the Sun. While this allows the telescope to work uninterrupted, maintaining it is beyond our range. 

Due to its restrictions, engineers knew its lifespan would be much shorter than Hubble’s. Thus, its missions were scheduled to only last five years. The James Webb has enough fuel to maintain its position at L2 for at least 10 years, but it will veer off in solar orbit sometime beyond that.

James Webb telescope space image
James Webb Telescope Image

©cometa geo/Shutterstock.com


The Hubble was the first space-based telescope and introduced the use of several innovative tools. The telescope features a 2.4 m (8ft) diameter primary mirror that can withstand extreme temperatures.

It has three cameras and three spectrographs, allowing it to observe ultraviolet and near-infrared wavelengths. It also features an interferometer that keeps it focused on the objects it studies. 

An incredible feature of the Hubble is that nearly every one of its original instruments have been replaced over its lifetime. This allowed the telescope to perform actions it was not originally intended. The Hubble had six instruments replaced, including:

  • High Speed Photomoeter
  • Faint Object Camera
  • Faint Object Spectrograph
  • Goddard High-Resolution Spectrograph
  • Wide Field and Planetary Camera
  • Wide Field and Planetary Camera 2

The design of the James Webb Space Telescope required innovative technology to accommodate it. The telescope features 18 gold-plated, hexagonal mirrors that align into one 8 m (21 ft) primary mirror.

It also has a 5-layer heat shield the size of a tennis court to protect its instruments from extreme heat from the sun. With delicate, laser-focused infrared capabilities, these instruments require extremely cold temperatures to perform as intended.

James Webb uses four primary instruments that study infrared frequencies from .6 to 28 microns. These include:

  • Near Infrared Imager and Slitless Spectrograph (NIRISS)
  • Near Infrared Spectrograph (NIRSpec)
  • Near Infrared Camera (NIRCam)
  • Mid Infrared Instrument (MIRI)

Of these instruments, the NIRSpec is highly impressive. This instrument uses microscopic slits to collect dispersed lightwaves from several observed objects at once. The NIRSpec can collect data from up to 100 objects at a time. This vastly increases the amount of work James Webb can do in its short lifespan.

Mission Goals

Hubble’s primary mission was to observe ultraviolet waves surrounding prominent objects such as planets, stars, and galaxies. Since its launch, the telescope has observed 43,500 celestial objects and collected 153 terabytes of data. 

Most notably, the Hubble is credited for the discovery of the age of the universe. The telescope also discovered the birth of stars, which hid within thick space dust.

The dust could not be observed in ultraviolet wavelengths, and in 2009, the telescope was equipped with a near-infrared camera. The discoveries of the Hubble guided the mission objectives for the next big telescope, which would focus even deeper on the infrared spectrum.

James Webb uses its massive primary mirror and infrared capabilities to accomplish four missions. Researchers want to see the development of galaxies at the start of the universe. They also plan on studying the early lifecycle of new stars, typically shrouded in space dust.

While researchers are doing this, others will examine the composition of exoplanets typically hidden from us.


Galaxy cosmos stars
Both Hubble and James Webb Telescopes capture images of young stars in faraway galaxies.


While the Hubble telescope was pivotal in studying our universe, it also brought excitement to space exploration. The telescope returned the first wide-scale image of the history of galaxies and incredible images of celestial bodies. 

One of its most famous images, the Pillars of Creation, depicted massive collections of star-forming space dust in the Eagle Nebula. The photo was originally shot in 1995 but was updated in 2020 with the telescope’s new infrared camera.

While the James Webb Space Telescope is more of a successor to Hubble in many ways, it does intend to carry on its legacy of providing stunning images. Within six months of its launch, the Webb produced images as stunning as its predecessor. Most recently, the Webb revealed the Tarantula Nebula in a way its never been seen before. 

Astronomers particularly admire this nebula for its conglomeration of very young stars. This photo exemplifies exactly what James Webb is capable of. Using infrared spectrographs and cameras, we can start to observe the birth of stars like these.

Hubble vs James Webb: Which One Is Better?

It’s hard to look at Hubble vs James Webb as direct competition because they complete different objectives. While Hubble views the universe primarily in ultraviolet wavelengths, the James Webb view is in near and mid-infrared. However, we can look at focal length, lifespan, and accomplishments to decide which is better.

In terms of distance, the James Webb Space Telescope can see as far back as 13.6 billion lightyears, which is about 9 times as far as the Hubble. Its massive mirror, as well as its infrared technology, allows it to peer through space dust and observe objects that the Hubble could not. In regards to its potential, the James Webb outclasses the Hubble. 

However, the Webb will not last as long as the Hubble due to its location at L2. It won’t see profound influence compared to its predecessor, which saw decades of upgrades and innovations. With groundbreaking discoveries and images that opened the public mind to space exploration, Webb will have difficulty eclipsing Hubble’s legacy.

Hubble vs James Webb: Further Reading

Hubble vs James Webb Space: Two Telescopes Compared FAQs (Frequently Asked Questions) 

What is the difference between the Hubble and James Webb Telescope?

The main differences between the Hubble and James Webb are their primary mirror size and scientific instruments. The James Webb features a primary mirror that is 21 feet in diameter, which is three times the size of Hubble’s. The Webb also views the universe in near and mid-infrared wavelengths, while the Hubble views it primarily in the ultraviolet.

Can the James Webb see further than the Hubble?

The James Webb can see as far back as 13.6 billion lightyears. This is about nine times as far as the Hubble can see.

How fast is Webb traveling?

Having reached its destination at the second Lagrange point (L2), the James Webb Space Telescope cruises in orbit around the Sun at about 720 miles per hour.

Is Hubble still in use?

The Hubble is in its 32nd year of active use. Engineers plan to decommission the telescope sometime around 2026.

What will happen to Hubble once we quit using it?

After the Hubble Space Telescope is decommissioned, it will slowly lose altitude in its orbit and descend back to Earth. Scientists expect that it will return to Earth on its own in the early to mid-2030s.

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