Compare Space Telescopes

Pick up to 4 telescopes to compare side-by-side. State lives in the URL — share the link and the comparison loads exactly as you left it.

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📊 Industry context

Space telescope data has underpinned 1.5 million+ scientific papers since 1990.

Attribute	Hubble Space Telescope (HST) NASA/ESA · 🇺🇸 Active · Last updated 2026-06-01 Trust: Agency-primaryⓘ Last verified 2026-06-01Remove ×	Chandra X-ray Observatory (CXO) NASA · 🇺🇸 Active · Last updated 2026-06-01 Trust: Agency-primaryⓘ Last verified 2026-06-01Remove ×	Kepler / K2 NASA · 🇺🇸 Trust: Agency-primaryⓘ Last verified 2026-06-01Remove ×
Agency	NASA/ESA	NASA	NASA
Status	Active	Active	Retired
Wavelength band	multi	x-ray	optical
Launch year	1990	1999	2009 – 2018
Orbit	Low Earth Orbit (LEO) ~547 km	Highly elliptical (perigee 10,000 km / apogee 140,000 km)	Earth-trailing heliocentric orbit
Mirror / aperture	2.4 mas of 1990-04-24^[1] ↑ Largest	1.2 mas of 1999-07-23^[1]Four pairs of nested grazing-incidence mirrors; effective aperture 0.04 m²	1.4 mas of 2009-03-07^[1]
Mass	11,110 kgas of 1990-04-24^[1] ↑ Heaviest	4,800 kgas of 1999-07-23^[1]Including HRMA mirror assembly	1,052 kgas of 2009-03-07^[1]
Wavelength range	0.115–2.5 μm (UV, optical, near-IR)	0.1–10 keV (soft to medium X-ray)	0.43–0.89 μm (optical)
Key missions	• Hubble Deep Field (1995) • Hubble Ultra Deep Field (2004) • Dark energy discovery with Type Ia SNe (1998) • Exoplanet atmosphere characterization • Over 1.6 million observations	• First X-ray image of Sgr A* (Milky Way black hole) • Bullet Cluster (direct dark matter evidence) • Cas A supernova remnant detailed imaging • Over 25 years operational lifetime	• Confirmed 2,662 exoplanets (primary mission) • Kepler-22b (first confirmed habitable-zone super-Earth) • K2 mission: 19 campaigns, +1,000 confirmed planets • Transit timing variations for multi-planet systems
Summary	The most scientifically productive telescope ever built. Launched in 1990 and serviced five times by Space Shuttle crews, Hubble has logged over 1.6 million observations and contributed to more than 21,000 peer-reviewed publications. Its image of the Hubble Deep Field fundamentally changed our understanding of galaxy formation.	NASA's flagship X-ray telescope and one of the Great Observatories. Chandra's angular resolution is 100× better than previous X-ray telescopes, enabling detailed imaging of supernovae remnants, galaxy clusters, and the region around supermassive black holes. Still operating after 25+ years despite being designed for a 5-year mission.	The mission that proved planets are abundant throughout the galaxy. Kepler monitored 150,000+ stars continuously for 4 years, finding that most stars host planets. A reaction wheel failure in 2013 ended the primary mission; the repurposed K2 mission (2014–2018) found 1,000+ additional planets before fuel ran out.

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Clear comparison

Fermi Gamma-ray Space Telescope+

NASA/DOE/international

Active

TESS (Transiting Exoplanet Survey Satellite)+

NASA

Active

James Webb Space Telescope (JWST)+

Nancy Grace Roman Space Telescope (Roman)+

NASA

In Development

Spitzer Space Telescope+

NASA

Retired

About this tool

All 9 major space telescopes with primary-source citations from NASA, ESA, STScI, and JPL. Pure URL state — bookmark or share the link and the comparison reproduces exactly.

📋 What changed recently

Jun 2026Updated Nancy Grace Roman Space Telescope launch estimate to Q2 2027 after schedule review.
Jun 2026Added Euclid DR2 data release reference and updated key discoveries entry.
May 2026Clarified Chandra cooling system status; updated TESS extended mission status to ongoing.

Attribute

Hubble Space Telescope (HST)

NASA/ESA · 🇺🇸

Active · Last updated 2026-06-01

Trust: Agency-primaryⓘ

Last verified 2026-06-01Remove ×

Chandra X-ray Observatory (CXO)

NASA · 🇺🇸

Active · Last updated 2026-06-01

Trust: Agency-primaryⓘ

Last verified 2026-06-01Remove ×

Kepler / K2

NASA · 🇺🇸

Trust: Agency-primaryⓘ

Last verified 2026-06-01Remove ×

Agency

NASA/ESA

NASA

Status

Active

Retired

Wavelength band

multi

x-ray

optical

Launch year

1990

1999

2009 – 2018

Orbit

Low Earth Orbit (LEO) ~547 km

Highly elliptical (perigee 10,000 km / apogee 140,000 km)

Earth-trailing heliocentric orbit

Mirror / aperture

2.4 mas of 1990-04-24^[1]

↑ Largest

1.2 mas of 1999-07-23^[1]Four pairs of nested grazing-incidence mirrors; effective aperture 0.04 m²

1.4 mas of 2009-03-07^[1]

Mass

11,110 kgas of 1990-04-24^[1]

↑ Heaviest

4,800 kgas of 1999-07-23^[1]Including HRMA mirror assembly

1,052 kgas of 2009-03-07^[1]

Wavelength range

0.115–2.5 μm (UV, optical, near-IR)

0.1–10 keV (soft to medium X-ray)

0.43–0.89 μm (optical)

Key missions

• Hubble Deep Field (1995)
• Hubble Ultra Deep Field (2004)
• Dark energy discovery with Type Ia SNe (1998)
• Exoplanet atmosphere characterization
• Over 1.6 million observations

• First X-ray image of Sgr A* (Milky Way black hole)
• Bullet Cluster (direct dark matter evidence)
• Cas A supernova remnant detailed imaging
• Over 25 years operational lifetime

• Confirmed 2,662 exoplanets (primary mission)
• Kepler-22b (first confirmed habitable-zone super-Earth)
• K2 mission: 19 campaigns, +1,000 confirmed planets
• Transit timing variations for multi-planet systems

Summary

The most scientifically productive telescope ever built. Launched in 1990 and serviced five times by Space Shuttle crews, Hubble has logged over 1.6 million observations and contributed to more than 21,000 peer-reviewed publications. Its image of the Hubble Deep Field fundamentally changed our understanding of galaxy formation.

NASA's flagship X-ray telescope and one of the Great Observatories. Chandra's angular resolution is 100× better than previous X-ray telescopes, enabling detailed imaging of supernovae remnants, galaxy clusters, and the region around supermassive black holes. Still operating after 25+ years despite being designed for a 5-year mission.

The mission that proved planets are abundant throughout the galaxy. Kepler monitored 150,000+ stars continuously for 4 years, finding that most stars host planets. A reaction wheel failure in 2013 ended the primary mission; the repurposed K2 mission (2014–2018) found 1,000+ additional planets before fuel ran out.