Hubble vs. James Webb Space Telescope
The Hubble Space Telescope and the James Webb Space Telescope are complementary, not competitors. Hubble reaches from ultraviolet through visible into the near-infrared; Webb is optimised for the infrared and sits a million and a half kilometres from Earth.
Key takeaways
- Hubble launched in 1990 and orbits Earth at around 540 km altitude.
- Webb launched in December 2021 and observes from the Sun–Earth L2 point.
- Their wavelength coverage overlaps in the near-infrared and is complementary elsewhere.
- Webb is not a replacement for Hubble; the two are designed for different science.
About this visual
The Hubble and James Webb Space Telescopes are complementary observatories, not competitors. Together they cover a wavelength range from the ultraviolet through the mid-infrared.
Hubble at a glance
- Launched: 24 April 1990 aboard STS-31
- Location: Low Earth orbit, ~540 km altitude
- Primary mirror: 2.4 m single mirror
- Wavelength range: ultraviolet, visible, near-infrared
- Servicing: Hubble was designed to be maintained by shuttle crews; five servicing missions between 1993 and 2009
James Webb at a glance
- Launched: 25 December 2021 on an Ariane 5 from Kourou
- Location: Sun–Earth L2 point, ~1.5 million km from Earth
- Primary mirror: 6.5 m segmented mirror (18 hexagonal segments)
- Wavelength range: near- and mid-infrared
- Servicing: Webb was not designed to be serviced
Why both matter
Hubble's ultraviolet and visible reach is unique among current space observatories, and it observes the same objects in short-wavelength light that Webb cannot see. Webb's much larger mirror and colder instruments reveal distant galaxies, dust-enshrouded protostars and exoplanet atmospheres that are essentially invisible to Hubble.
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Sources and methodology
Values verified against official mission and archive pages on the updated date shown above. Numeric quantities are cited to the precision typical of introductory astronomy references.