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.
Space telescope data has underpinned 1.5 million+ scientific papers since 1990.
| Attribute | Hubble Space Telescope (HST) NASA/ESA · 🇺🇸 Active · Last updated 2026-06-01Trust: Agency-primaryⓘ Last verified Remove × | Fermi Gamma-ray Space Telescope NASA/DOE/international · 🇺🇸 Active · Last updated 2026-06-01Trust: Agency-primaryⓘ Last verified Remove × | Chandra X-ray Observatory (CXO) NASA · 🇺🇸 Active · Last updated 2026-06-01Trust: Agency-primaryⓘ Last verified Remove × |
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| Agency | NASA/ESA | NASA/DOE/international | NASA |
| Status | Active | Active | Active |
| Wavelength band | multi | gamma-ray | x-ray |
| Launch year | 1990 | 2008 | 1999 |
| Orbit | Low Earth Orbit (LEO) ~547 km | Low Earth Orbit (LEO) ~550 km, 25.6° inclination | Highly elliptical (perigee 10,000 km / apogee 140,000 km) |
| Mirror / aperture | 2.4 mas of [1] ↑ Largest | — | 1.2 mas of [1]Four pairs of nested grazing-incidence mirrors; effective aperture 0.04 m² |
| Mass | 11,110 kgas of [1] ↑ Heaviest | 4,303 kgas of [1] | 4,800 kgas of [1]Including HRMA mirror assembly |
| Wavelength range | 0.115–2.5 μm (UV, optical, near-IR) | 20 MeV – 300 GeV (LAT); 8 keV – 40 MeV (GBM) | 0.1–10 keV (soft to medium X-ray) |
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| 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. | The most sensitive gamma-ray telescope ever flown. Fermi's Large Area Telescope (LAT) has detected over 6,000 gamma-ray sources — pulsars, blazars, gamma-ray bursts, and potentially dark matter annihilation signals. Its GBM instrument records ~300 gamma-ray bursts per year. | 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. |
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.