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 | James Webb Space Telescope (JWST) NASA/ESA/CSA · 🇺🇸 Active · Last updated 2026-06-01Trust: Agency-primaryⓘ Last verified Remove × | TESS (Transiting Exoplanet Survey Satellite) NASA · 🇺🇸 Active · Last updated 2026-06-01Trust: Agency-primaryⓘ Last verified Remove × | |
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| Agency | NASA/ESA/CSA | NASA | NASA |
| Status | Active | Active | Retired |
| Wavelength band | infrared | optical | optical |
| Launch year | 2021 | 2018 | 2009 – 2018 |
| Orbit | Sun-Earth L2 point (~1.5 million km from Earth) | High Earth orbit (P/2 lunar resonance orbit) | Earth-trailing heliocentric orbit |
| Mirror / aperture | 6.5 mas of [1]18 gold-coated beryllium hexagonal segments ↑ Largest | — | 1.4 mas of [1] |
| Mass | 6,200 kgas of [1]Includes 2,447 kg for the primary mirror assembly ↑ Heaviest | 362 kgas of [1] | 1,052 kgas of [1] |
| Wavelength range | 0.6–28.5 μm (optical red through mid-IR) | 0.6–1.0 μm (red optical) | 0.43–0.89 μm (optical) |
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| Summary | The most powerful space telescope ever launched. Operating at -233°C at the L2 point, JWST can observe the universe's first light from ~100 million years after the Big Bang. Its first full-color images, released July 2022, immediately set records for the most distant galaxies observed. | NASA's all-sky transit photometry survey, successor to Kepler. TESS monitors nearly the entire sky in 27-day sectors using four wide-field cameras, targeting the 200,000 brightest stars nearest to Earth. Its targets are close enough for atmospheric follow-up by ground telescopes and JWST. | 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.