NASA

United States · Earth orbit · Science / Earth orbit

First U.S. satellite; discovered the Van Allen radiation belts.

United States · Earth orbit · Space physics

Confirmed the existence of the trapped radiation belts discovered by Explorer 1.

United States · Moon · Lunar probe

First U.S. lunar probe; failed to reach the Moon but returned radiation data.

United States · Moon · Lunar probe

Third stage of the launch vehicle failed to ignite; did not reach orbit.

United States · Earth orbit · Geodesy / Earth science

Early geodesy satellite; long-lived orbital tracking improved Earth-shape studies.

United States · Earth orbit · Earth science

Returned the first crude image of Earth from orbit.

United States · Earth orbit · Meteorology

First successful television weather satellite.

United States · Earth / space · Lunar technology / space science

Lunar probe test mission; failed to leave low Earth orbit.

United States · Earth / space · Lunar technology / space science

Launch vehicle failed to restart; stranded in low Earth orbit.

United Kingdom / United States · Earth orbit · Ionospheric science

First British satellite; conducted ionospheric research.

United States · Venus · Planetary flyby

First successful interplanetary mission.

United States · Earth orbit · Solar observatory

First Orbiting Solar Observatory.

United States · Earth orbit · Space technology / communications science

First successful geosynchronous satellite; enabled space-environment observations.

United States · Earth orbit · Geophysics

First Orbiting Geophysical Observatory.

United States · Moon · Lunar impactor

First successful close-up U.S. lunar images.

United States · Earth orbit · Human spaceflight / science

Crewed research mission; first U.S. spacewalk.

United States · Mars · Planetary flyby

First close-up images of Mars.

United States · Moon · Lunar lander

First U.S. soft lunar landing.

United States · Moon · Lunar orbiter

Completed global photographic mapping for Apollo site selection.

United States · Moon · Human spaceflight

First crewed mission to orbit the Moon.

United States · Moon · Crewed lunar landing

First humans landed on the Moon.

United States · Mars · Planetary flyby

Returned Mars images and atmospheric data.

United States · Mars · Planetary flyby

Companion Mars flyby; returned imaging and atmospheric data.

United States / Italy · Earth orbit · X-ray astronomy

First satellite dedicated to X-ray astronomy.

United States · Mars · Planetary orbiter

First spacecraft to orbit another planet.

United States · Moon · Crewed lunar landing

Most recent crewed lunar landing; completed Apollo surface exploration.

United States · Earth orbit · Ultraviolet astronomy

Major ultraviolet observatory.

United States · Earth orbit · Earth observation

First civilian Earth-resources satellite.

United States · Jupiter / outer Solar System · Planetary flyby

First spacecraft to traverse the asteroid belt and fly by Jupiter.

United States · Jupiter / Saturn · Planetary flyby

First flyby of Saturn (1979).

United States · Earth orbit · Space station

First U.S. space station; supported long-duration crewed research.

Germany / United States · Sun · Solar physics

Solar probe studying the inner heliosphere.

United States · Venus / Mercury · Planetary flyby

First Mercury mission and first gravity-assist trajectory.

United States / Soviet Union · Earth orbit · Human spaceflight / cooperation

First international crewed-spaceflight mission and first U.S.–Soviet docking.

United States · Earth orbit · X-ray astronomy

X-ray source localization mission.

United States · Mars · Orbiter / lander

First successful long-lived Mars lander; returned extensive surface science.

United States · Earth orbit · High-energy astronomy

Broad-band X-ray and gamma-ray survey observatory.

United States · Outer Solar System · Planetary grand tour

Transformative flybys of the giant planets; both later entered interstellar space.

United States / ESA · Sun–Earth L1 / comet · Heliophysics / comet flyby

First spacecraft placed at Sun–Earth L1; later flew by comet Giacobini–Zinner.

United States · Earth orbit · Oceanography

First satellite designed for global oceanographic remote sensing.

United States · Earth orbit · X-ray astronomy

First fully imaging X-ray telescope.

United States · Earth orbit · Solar observatory

Observed solar flares and the solar maximum.

United States · Earth orbit · Human spaceflight

First Space Shuttle flight; inaugurated reusable orbital spacecraft operations.

United States / Netherlands / United Kingdom · Earth orbit · Infrared astronomy

First all-sky infrared survey satellite.

United States · Earth orbit · Cosmology

Measured the cosmic microwave background spectrum and anisotropy.

United States · Jupiter · Orbiter / atmospheric probe

First Jupiter orbiter; revealed complex Jovian-system science.

United States · Venus · Planetary orbiter

Mapped most of Venus with radar.

NASA / ESA · Earth orbit · Space observatory

Landmark optical/UV/near-IR observatory; transformed astronomy.

Germany / United States / United Kingdom · Earth orbit · X-ray astronomy

All-sky X-ray survey observatory.

ESA / NASA · Sun · Solar observatory

First mission to study the heliosphere above and below the Sun’s poles.

Japan / United States / United Kingdom · Earth orbit · Solar X-ray astronomy

Observed solar flares and coronal activity.

United States · Mars · Planetary orbiter

Lost before Mars-orbit insertion.

United States · Earth orbit · Space physics

Studied energetic particles in Earth’s magnetosphere.

NASA / CNES · Earth orbit · Earth science

Precision ocean-altimetry mission; foundational climate and ocean data.

United States · Moon · Lunar orbiter

Global lunar mapping; evidence consistent with polar ice.

United States · Sun–Earth L1 · Heliophysics

Solar-wind and magnetospheric science mission.

United States · Earth orbit · X-ray astronomy

Timing studies of X-ray sources.

ESA / NASA · Sun–Earth L1 · Solar observatory

Long-running solar and heliospheric observatory.

United States · Mars · Planetary orbiter

Established long-term, high-resolution global Mars mapping.

United States · Asteroid Eros · Asteroid orbiter / lander

First spacecraft to orbit and land on an asteroid.

ESA / NASA · Sun–Earth L1 · Solar observatory

Solar and heliospheric observatory.

United States · Sun–Earth L1 · Heliophysics

Solar wind and energetic particle observatory.

NASA / ESA / ASI · Saturn / Titan · Orbiter / lander

Cassini orbited Saturn; Huygens made the first landing in the outer Solar System.

United States · Mars · Lander / rover

First Mars rover mission; demonstrated low-cost landing approach.

United States · Asteroid / comet · Technology / planetary flyby

Ion-propulsion technology mission; flew by asteroid Braille and comet Borrelly.

United States · Moon · Lunar orbiter

Strengthened evidence for hydrogen at lunar poles.

United States · Earth orbit · Solar observatory

High-resolution solar transition-region and coronal imaging.

United States · Earth orbit · Space observatory

Flagship X-ray observatory.

United States · Earth orbit · Ultraviolet astronomy

Far-ultraviolet spectroscopy observatory.

United States · Earth orbit · Earth science

Flagship Earth Observing System satellite.

United States · Earth orbit · Magnetospheric science

Imaged Earth’s magnetosphere and aurora.

United States · Sun–Earth L1 / Earth · Solar-wind sample return

Collected solar-wind samples; capsule crash limited recovery but useful material was retrieved.

United States · Mars · Planetary orbiter

Mapped elemental composition and found evidence of near-surface water ice.

United States · Earth orbit · Upper-atmosphere science

Thermosphere-ionosphere-mesosphere energetics mission.

United States · Earth orbit · Earth science

Water-cycle and climate-observing satellite.

United States · Earth-trailing orbit · Infrared astronomy

Great Observatory infrared mission.

United States · Mars · Mars rovers

Found extensive evidence of ancient watery environments.

United States · Comet Wild 2 · Comet sample return

First mission to return cometary material to Earth.

United States / United Kingdom / Italy · Earth orbit · Gamma-ray astronomy

Rapid-response gamma-ray burst observatory.

Japan / United States / United Kingdom / ESA · Earth orbit · Solar observatory

Solar magnetic-field and corona mission.

ESA / NASA / ASI · Titan · Planetary lander

First landing in the outer Solar System.

United States · Mars · Planetary orbiter

High-resolution imaging and relay supporting Mars exploration.

United States / France · Earth orbit · Earth science

Lidar measurements of clouds and aerosols.

United States · Vesta / Ceres · Dwarf planet / asteroid orbiter

First spacecraft to orbit two extraterrestrial bodies.

United States · Earth orbit · Magnetospheric science

Multi-spacecraft mission studying substorms.

United States / international · Earth orbit · Gamma-ray astronomy

High-energy gamma-ray observatory.

United States · Mars · Mars lander

Confirmed water ice in the Martian arctic.

United States · Earth-trailing solar orbit · Space observatory

Revolutionized exoplanet discovery and occurrence-rate studies.

United States · Moon · Lunar gravity science

Twin spacecraft mapped the Moon’s gravity field.

United States · Jupiter · Planetary orbiter

Entered Jupiter orbit in 2016; studies interior and atmosphere.

United States · Mars · Mars rover

Established that Gale Crater once offered habitable conditions.

United States · Earth orbit · X-ray astronomy

Focusing hard X-ray telescope.

United States · Earth orbit · Solar observatory

Solar interface-region imaging spectrograph.

United States · Earth orbit · Earth science

Atmospheric carbon-dioxide observatory.

United States · Pluto / Kuiper Belt · Dwarf planet flyby

First close exploration of Pluto; later flew by Arrokoth.

United States · Asteroid Bennu · Asteroid sample return

Collected Bennu material; sample returned to Earth in 2023.

United States · International Space Station · X-ray astronomy

X-ray timing instrument studying neutron stars.

United States · Mars · Mars lander

First dedicated Martian geophysics mission; detected marsquakes.

United States · Sun · Solar observatory

First mission to fly through the solar corona.

United States · Earth orbit · Exoplanet astronomy

All-sky transiting-exoplanet survey.

United States · Mars · Rover / helicopter

Mars sample-caching mission; Ingenuity achieved first powered flight on another world.

United States / Italy · Earth orbit · X-ray astronomy

X-ray polarimetry observatory.

NASA / ESA / CSA · Sun–Earth L2 · Space observatory

Flagship infrared observatory for early-universe, exoplanet and solar-system science.

ESA / NASA · Sun · Solar observatory

Studies the Sun and heliosphere, including high-latitude solar views.

United States / international · Moon · Lunar test flight

Uncrewed Orion mission completed a lunar-orbit test for the Artemis programme.

United States · Asteroid Dimorphos · Planetary defence

First demonstration of kinetic-impact asteroid deflection.

United States · International Space Station · Earth science

Maps mineral dust sources and their climate effects.

United States · Earth / Bennu sample · Asteroid sample return

Delivered Bennu samples to Earth.

United States · Asteroid Psyche · Asteroid orbiter

En route to investigate a metal-rich asteroid and planetary building blocks.

Japan / NASA · Earth orbit · X-ray astronomy

High-resolution X-ray spectroscopy observatory.

United States · Europa · Planetary orbiter

Launched to investigate Europa’s habitability during planned flybys.

United States · Earth orbit · Earth science

Ocean colour, aerosol and cloud-polarimetry mission.

Firefly Aerospace / NASA CLPS · Moon · Commercial lunar lander

Successful upright landing with ten NASA science and technology payloads.

NASA / ISRO · Earth orbit · Earth science

Joint radar mission monitoring land, ice, hazards and ecosystems.

United States · Earth orbit · Heliophysics

Four-spacecraft mission imaging the corona and solar wind.

United States · Earth orbit · Space observatory

All-sky near-infrared spectral survey of galaxies, stars and cosmic ices.

United States / international · Moon · Human spaceflight

Crewed lunar flyby; first people around the lunar far side since Apollo.