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Space telescope data has underpinned 1.5 million+ scientific papers since 1990.
| Attribute | Fermi Gamma-ray Space Telescope NASA/DOE/international · 🇺🇸 Active · Last updated 2026-06-01Trust: Agency-primaryⓘ Last verified Remove × | ||
|---|---|---|---|
| Agency | NASA | NASA/DOE/international | NASA |
| Status | Retired | Active | Retired |
| Wavelength band | infrared | gamma-ray | optical |
| Launch year | 2003 – 2020 | 2008 | 2009 – 2018 |
| Orbit | Earth-trailing heliocentric orbit | Low Earth Orbit (LEO) ~550 km, 25.6° inclination | Earth-trailing heliocentric orbit |
| Mirror / aperture | 0.85 mas of [1] | — | 1.4 mas of [1] ↑ Largest |
| Mass | 950 kgas of [1] | 4,303 kgas of [1] ↑ Heaviest | 1,052 kgas of [1] |
| Wavelength range | 3.6–160 μm (mid-to-far infrared) | 20 MeV – 300 GeV (LAT); 8 keV – 40 MeV (GBM) | 0.43–0.89 μm (optical) |
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| Summary | NASA's infrared Great Observatory, operating 2003–2020. Best known for discovering the TRAPPIST-1 system of 7 Earth-sized planets, including 3 in the habitable zone (with ground telescopes). Ran out of cryogen in 2009 but continued 'warm mission' until retirement in January 2020. | 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. | 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. |
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.