COSMOS / 32 MILESTONES
The path of an idea
into orbit.
From telescopes to planets, from first flights to distant worlds.
This selection traces how discoveries complement each other. Every event links to its source; it is not a complete chronology of all science and space history. Unless stated otherwise, dates follow the calendars in international mission records.
Scientific discovery
A new sky through the telescope
Galileo’s telescopic observations changed how the sky was studied.
Event source ↗32 source-linked milestones.
Scientific discovery
A new sky through the telescope
Galileo’s telescopic observations changed how the sky was studied.
Spaceflight
First liquid-fuelled rocket flight
Robert Goddard’s experiment was an important step in modern rocket technology.
Spaceflight
Sputnik 1
The first artificial satellite symbolised the beginning of the space age.
Spaceflight
Explorer 1
The first American satellite contributed to discovering Earth’s radiation belts.
Spaceflight
Humans reached orbit
Yuri Gagarin flew around Earth aboard Vostok 1.
Spaceflight
The first woman in space
Valentina Tereshkova went to space aboard Vostok 6.
Spaceflight
Apollo 8 in lunar orbit
Humans first reached orbit around another celestial body.
Spaceflight
First steps on the Moon
Armstrong and Aldrin landed while Collins remained in orbit.
Spaceflight
Mariner 9 reached Mars
It became the first artificial orbiter of another planet.
Spaceflight
Viking 1 landed on Mars
A new period of extended surface investigations began.
Spaceflight
The Voyager journey began
Two spacecraft set out to investigate the outer planets and beyond.
Spaceflight
First Space Shuttle flight
Columbia tested a new flight system on STS-1.
Spaceflight
Sally Ride’s flight
Ride became the first American woman in space on STS-7.
Observatories
Hubble launched
A long observational legacy began in Earth orbit.
Scientific discovery
51 Pegasi b
The discovery of an exoplanet orbiting a Sun-like star was announced.
Spaceflight
First ISS module
The launch of Zarya began construction of the orbital laboratory.
Spaceflight
Cassini in Saturn orbit
The Saturn system opened to extended close investigation.
Spaceflight
Huygens landed on Titan
ESA’s probe reached the surface of Saturn’s moon.
Observatories
Kepler’s planet hunt
Exoplanet research using the transit method expanded on a large scale.
Spaceflight
Curiosity on Mars
The rover began investigating Gale Crater’s history of habitability.
Spaceflight
Landing on a comet
Rosetta’s Philae probe reached the surface of 67P.
Spaceflight
Pluto flyby
New Horizons imaged the Pluto system up close.
Scientific discovery
Gravitational-wave announcement
LIGO announced the first direct detection, measured in 2015.
Scientific discovery
First image of a black hole
The Event Horizon Telescope revealed the ring of light around M87*.
Spaceflight
Perseverance in Jezero
The rover landed to investigate ancient environments on Mars.
Observatories
Webb reached space
The infrared observatory launched aboard Ariane 5.
Observatories
Webb’s first full-colour selection
The first science images revealed details of the infrared universe.
Observatories
Euclid’s journey
ESA’s cosmology mission launched to investigate the universe’s large-scale structure.
Spaceflight
A Bennu sample on Earth
The OSIRIS-REx sample capsule returned to Earth.
Türkiye
The first Turkish astronaut’s journey
Alper Gezeravcı set out for the ISS on Ax-3 to conduct scientific experiments.
Spaceflight
Europa Clipper departed
The spacecraft began its journey to investigate icy Europa.
Observatories
Gaia completed its sky scanning
Scientific analysis of the collected measurements continues after observations end.
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Editorial review: . Mission status and catalogues can change; consult the official source for current information.