Cosmonaut Alexei Leonov exited his Voskhod 2 capsule for 12 minutes, becoming the first human to walk in space, tethered by a slender umbilical cord.

Ferdinand Magellan's expedition sailed out of the strait bearing his name into a vast, unknown ocean he named the Pacific.

Dutch astronomer Christiaan Huygens discovered Titan, Saturn's largest moon, using a refracting telescope of his own design.

Astronomer Johann Galle located Neptune within an hour of resuming his search, guided by predictions from Urbain Le Verrier's mathematics.

Berlin astronomer Johann Galle spotted Neptune within a degree of its predicted position, confirming a planet found first by mathematics, not a telescope.

Neil Armstrong, who would become the first human to walk on the Moon, was born on a farm near Wapakoneta, Ohio.

The Lowell Observatory announced that the newly discovered ninth planet would be named Pluto, a suggestion from an 11-year-old English schoolgirl named Venetia Burney.

Edwin 'Buzz' Aldrin, who would become the second human to walk on the Moon during Apollo 11, was born in Montclair, New Jersey.

Clyde Tombaugh, a 24-year-old self-taught astronomer, spotted a faint moving speck on photographic plates at Lowell Observatory, identifying the object later named Pluto.

Lowell Observatory announced the name Pluto for the ninth planet, chosen from a suggestion by 11-year-old Venetia Burney of Oxford, England.

Lowell Observatory announced that 24-year-old Clyde Tombaugh had discovered a ninth planet, spotted by comparing photographic plates taken weeks earlier.

News of Clyde Tombaugh's discovery of Pluto, made weeks earlier at Lowell Observatory, spread globally, briefly crowning a ninth planet.

The Lowell Observatory announced the discovery of Pluto, a new ninth planet found by 24-year-old astronomer Clyde Tombaugh.

Astronomer Clyde Tombaugh, comparing photographic plates at Lowell Observatory, confirmed a moving object that would soon be announced as the ninth planet, Pluto.

Yuri Gagarin, who would become the first human in space, was born in the village of Klushino in the Soviet Union.

Soviet engineers at Baikonur completed final preparations on a beach-ball-sized satellite that would launch the next day and stun the world.

The Soviet Union launched Sputnik 1, a 184-pound aluminum sphere, becoming the first artificial satellite to orbit Earth.

Three days after Sputnik's launch, the Soviet satellite carrying the dog Laika continued its orbit, deepening American anxiety over the Space Race.

Soviet space officials confirmed the stray dog Kudryavka, soon renamed Laika, would fly aboard Sputnik 2, the first living creature launched into orbit.

The Soviet Union launched Sputnik 2, carrying the dog Laika into orbit as the first living creature to circle the Earth.

The Soviet Union launches Sputnik 2 carrying Laika, the first living creature to orbit Earth, though she dies within hours from overheating.

USS Nautilus, the world's first nuclear-powered submarine, becomes the first vessel to reach the North Pole, cruising beneath the Arctic ice.

NASA formally absorbed the Jet Propulsion Laboratory from the U.S. Army, folding America's rocket research into the new civilian space agency.

The National Aeronautics and Space Administration officially began operations, absorbing the old NACA to compete with the Soviets in space.

The U.S. Army launches SCORE, the world's first communications satellite, which broadcasts a recorded Christmas message from President Eisenhower to the world.

Data radioed from America's first satellite, launched days earlier, began revealing an unexpected band of intense radiation encircling Earth.

Data from America's first satellite, Explorer 1, helped physicist James Van Allen confirm the radiation belts encircling Earth that now bear his name.

Explorer 1 lifted off from Cape Canaveral atop a Juno I rocket, making the United States the second nation to reach orbit after the Soviet Union.

Explorer 1 lifted off from Cape Canaveral, making the United States the second nation to reach orbit, months after Sputnik.

Data from Explorer 1, America's first satellite, confirmed the existence of the Van Allen radiation belts encircling Earth, launched just days earlier.

America's first satellite, Explorer 1, entered orbit just after midnight, discovering the Van Allen radiation belts and answering Sputnik.

NASA's early rocket program advanced weather observation as Vanguard-related research pushed satellite meteorology forward in the space race's opening years.

The Soviet satellite that had carried the dog Laika into orbit five months earlier finally burned up in the atmosphere after 2,570 orbits.

President Eisenhower signed the National Aeronautics and Space Act, creating NASA and launching America's civilian space program amid Cold War panic over Sputnik.

The Soviet probe Luna 3 began transmitting the first-ever photographs of the Moon's far side, a hemisphere never before seen by human eyes.

The Soviet Union launched Luna 1, the first spacecraft to escape Earth's gravity, though it missed the Moon and became the first artificial object to orbit the Sun.

The Soviet probe Luna 1, intended to hit the Moon, missed by about 6,000 kilometers and became the first human-made object to orbit the Sun.

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NASA's Explorer 6 mission — intended to expand study of Earth's radiation belts — failed to reach orbit when its Thor-Able booster malfunctioned.

America's Vanguard SLV-5 satellite launch failed when the rocket's second stage malfunctioned, another setback in the early space race against the Soviets.

Soviet spacecraft Sputnik 5 returned to Earth carrying the dogs Belka and Strelka, the first animals to orbit Earth and survive.

NASA launched the uncrewed Mercury-Atlas 4 capsule, completing one orbit of Earth and testing systems ahead of crewed spaceflights.

The Soviet Union launched Sputnik 9, sending a dog named Chernushka into orbit to test life-support systems ahead of the first crewed spaceflight.

Soviet officials gave final approval for Yuri Gagarin's spaceflight aboard Vostok 1, setting the stage for humanity's first journey into orbit days later.

Soviet cosmonaut Yuri Gagarin became the first human to journey into outer space, completing one orbit of Earth aboard Vostok 1 in 108 minutes.

Alan Shepard became the first American in space, riding the Freedom 7 capsule on a 15-minute suborbital hop launched from Cape Canaveral.

The UN General Assembly passed a resolution encouraging international cooperation in the peaceful uses of outer space amid Cold War rivalry.

President John F. Kennedy asked Congress to commit the nation to landing a man on the Moon before the decade's end, launching the Apollo program.

President John F. Kennedy delivered his famous speech at Rice University, committing America to landing on the Moon before decade's end.

Astronaut Wally Schirra splashed down safely after piloting Sigma 7 through six orbits, proving America could conduct a controlled, fuel-efficient spaceflight.

NASA officials moved toward adopting Lunar Orbit Rendezvous as the mission mode for landing astronauts on the Moon, a decision that shaped the entire Apollo program.

NASA's Mariner 2 spacecraft executed a critical mid-course correction burn, adjusting its trajectory toward Venus in humanity's first successful planetary flyby mission.

The U.S. Army's Nike Zeus anti-ballistic missile program conducted a key intercept test during heightened Cold War tensions, part of early efforts to defend against intercontinental missile attack.

NASA launched Mariner 2 on November... wait check date

NASA's Mariner 2 became the first spacecraft to fly by another planet, passing within 21,600 miles of Venus and confirming its crushing heat.

John Glenn became the first American to orbit Earth, circling the planet three times aboard Friendship 7 in under five hours.

Days after becoming the first American to orbit Earth, John Glenn was celebrated with parades as Cold War space competition intensified.

Ground controllers executed a critical mid-course correction on Mariner 2, keeping America's first successful interplanetary probe on track toward Venus.

Engineers performed the first successful mid-course trajectory correction of an interplanetary spacecraft, keeping Mariner 2 on target for Venus.

NASA and AT&T launched Telstar 1, the first commercial communications satellite, enabling live transatlantic television broadcasts for the first time in history.

NASA's Mariner 1 probe, intended to fly past Venus, veered off course moments after launch and had to be destroyed, one of the earliest and most infamous computer-bug failures in spaceflight history.

Telstar 1, the first active communications satellite, relayed live television images between the United States and Europe, shrinking the world overnight.

NASA launched Syncom 2, the first satellite placed in geosynchronous orbit, transforming global telecommunications and broadcasting.

The Soviet Union launched Molniya-1, its first satellite designed for long-distance communications and television broadcast relay across the vast country.

Valentina Tereshkova launched aboard Vostok 6, becoming the first woman to fly in space and orbiting Earth 48 times over nearly three days.

Valentina Tereshkova launched aboard Vostok 6, becoming the first woman in space and orbiting Earth 48 times over nearly three days.

Soviet cosmonaut Valentina Tereshkova landed after nearly three days in orbit, completing the mission that made her the first woman in space.

Soviet cosmonaut training intensified in the final days before Valentina Tereshkova's historic flight, part of the broader June 1963 Vostok 6 mission window.

The Soviet Union launches Venera 3, which would become the first human-made object to reach the surface of another planet.

NASA launched Gemini 7 with astronauts Frank Borman and Jim Lovell for a grueling 14-day mission testing long-duration spaceflight and orbital rendezvous.

Intelsat I, nicknamed 'Early Bird,' launches into orbit as the world's first commercial communications satellite, linking Europe and North America instantly.

A Titan II missile silo fire at an Air Force base near Searcy, Arkansas, killed 53 civilian workers, one of the deadliest industrial accidents in U.S. Cold War missile history.

Astronaut Ed White became the first American to walk in space, floating outside Gemini 4 for 23 minutes tethered by a lifeline.

Mariner 4 sent back humanity's first close-up images of Mars, showing a cratered, moon-like desert that ended dreams of canals and civilization.

NASA's Mariner 4 spacecraft flew past Mars, transmitting the first close-up photographs ever taken of another planet's surface.

Astronauts Gordon Cooper and Charles Conrad returned to Earth after eight days in orbit, then the longest human spaceflight ever completed.

NASA's Gemini 5, having spent nearly eight days testing rendezvous and life-support systems in orbit, splashed down safely in the Atlantic Ocean.

Gemini 11 launched with Pete Conrad and Richard Gordon aboard, achieving a record altitude and a first tethered spacewalk maneuver.

The Soviet Luna 12 probe entered lunar orbit and began photographing the Moon's surface in unprecedented detail, feeding Cold War competition to map landing sites.

Gemini 12 splashed down safely in the Atlantic, closing out NASA's Gemini program and proving spacewalking techniques essential for the coming Apollo missions.

The Soviet probe Venera 3 crashed into Venus, becoming the first human-made object to reach the surface of another planet, though it failed to transmit data.

Astronauts Tom Stafford and Gene Cernan completed Gemini 9A, a three-day mission plagued by a failed docking attempt with an Agena target vehicle stuck in a 'mad, tumbling wreck.'

NASA's Surveyor 1 became the first American spacecraft to soft-land on the Moon, transmitting over 11,000 photographs back to Earth.

NASA launched Surveyor 1 from Cape Kennedy, the first US mission designed to achieve a soft landing on the lunar surface.

NASA's Surveyor 1 touched down softly on the Moon's Ocean of Storms, becoming the first American spacecraft to achieve a soft lunar landing.

NASA launched Gemini 9A carrying Tom Stafford and Eugene Cernan, days after their original target vehicle had failed to reach orbit properly.

NASA's Lunar Orbiter 1 launched from Cape Canaveral, becoming the first American spacecraft to orbit the Moon and photograph potential Apollo landing sites.

NASA launched Gemini 9A with astronauts Thomas Stafford and Eugene Cernan, testing rendezvous and spacewalk techniques crucial for the coming Apollo Moon missions.

Sergei Korolev, the secretive chief designer behind Sputnik and Gagarin's flight, died in Moscow following routine surgery, dealing a crushing blow to the Soviet space program.

The Soviet probe Venera 4 became the first spacecraft to transmit data directly from the atmosphere of another planet, descending into Venus's crushing clouds.

NASA launched Apollo 4, the first uncrewed test flight of the massive Saturn V rocket, proving the vehicle that would ultimately carry astronauts to the Moon.

A flash fire sweeps through the Apollo 1 command module during a launch rehearsal, killing astronauts Gus Grissom, Ed White, and Roger Chaffee.

The US, USSR, and UK signed the Outer Space Treaty, banning nuclear weapons in orbit and declaring space the province of all mankind.

A flash fire swept through the Apollo 1 command module during a launch rehearsal, killing astronauts Grissom, White, and Chaffee in seconds.

Days after the Apollo 1 fire killed three astronauts, NASA officials faced early scrutiny as investigators began probing the spacecraft's fatal design flaws.

Weeks after the Apollo 1 fire killed three astronauts, NASA officials and congressional investigators intensified scrutiny into spacecraft safety failures, reshaping the Apollo program's engineering culture.

NASA publicly detailed its schedule for crewed lunar landing missions as Apollo program planning accelerated, weeks before tragedy struck the program.

NASA launched Apollo 7, its first crewed mission after the fatal Apollo 1 fire, testing the redesigned command module in Earth orbit for eleven days.

The Soviet uncrewed spacecraft Zond 6 looped around the Moon and photographed its far side before a parachute failure crash-landed it back on Earth.

Astronauts Frank Borman, Jim Lovell, and William Anders returned safely to Earth after humanity's first crewed voyage around the Moon.

Astronauts Frank Borman, Jim Lovell, and Bill Anders continue their historic lunar orbits, the first humans ever to leave Earth's gravitational pull and circle another world.

Apollo 8 launched atop a Saturn V, carrying Borman, Lovell, and Anders toward becoming the first humans to orbit the Moon.

Apollo 8 launched from Cape Kennedy, carrying the first humans to leave Earth's orbit and travel to the Moon.

Apollo 8 astronauts, the first humans to orbit the Moon, read from Genesis on live television as Earth rose over the lunar horizon.

Apollo 8, fresh from becoming the first crewed mission to orbit the Moon, was recovered safely by USS Yorktown on Christmas morning.

Apollo 8 returned safely to Earth, splashing down in the Pacific after becoming the first crewed mission to orbit the Moon.

NASA's Apollo 8 crew splashed down safely in the Pacific Ocean, completing humanity's first crewed voyage around the Moon and returning triumphant days before the new year.

NASA launched Apollo 5, the first uncrewed test flight of the Lunar Module, in Earth orbit ahead of crewed moon landing attempts.

An unmanned Apollo 5 mission launched to test the lunar module's engines in orbit, a critical step toward landing astronauts on the Moon.

Astronomers announced the discovery of a pulsar within the Crab Nebula, confirming that pulsars are the rapidly spinning remnants of supernova explosions.

NASA launches the unmanned Apollo 6 test flight, exposing dangerous 'pogo' vibrations that engineers scrambled to fix before crewed lunar missions.

The Concorde prototype broke the sound barrier for the first time, proving the Anglo-French jet could achieve sustained supersonic commercial flight.

Apollo 12 lifted off from Kennedy Space Center and was struck by lightning 36 seconds later, briefly knocking out its instruments before the crew restored power.

Apollo 12 launched from Florida in a rainstorm, was struck by lightning 36 seconds after liftoff, and still went on to make the second crewed Moon landing.

Apollo 12 lifted off and was struck by lightning just 36 seconds later, knocking out telemetry before astronauts restored power and continued to the Moon.

Apollo 12 blasted off from Cape Kennedy and was struck by lightning 36 seconds later, briefly knocking out onboard power before crew and ground control saved the mission.

Apollo 12 launched from Kennedy Space Center and was struck by lightning twice within a minute of liftoff, briefly knocking out its instruments.

Astronauts Pete Conrad and Alan Bean conducted their second moonwalk of the Apollo 12 mission, retrieving parts from the earlier Surveyor 3 probe.

Pete Conrad and Alan Bean conducted their second moonwalk of the Apollo 12 mission, collecting lunar samples and retrieving parts from the unmanned Surveyor 3 probe.

Astronauts Pete Conrad and Alan Bean land the Intrepid lunar module in the Moon's Ocean of Storms, the second crewed Moon landing in history.

Apollo 12 astronauts Pete Conrad, Dick Gordon, and Alan Bean returned safely to Earth after the second crewed Moon landing mission.

Apollo 12 astronauts return to Earth after the second successful crewed Moon landing, splashing down in the Pacific Ocean.

Soviet spacecraft Soyuz 4 and Soyuz 5 perform the first docking of two crewed spacecraft in orbit, allowing cosmonauts to transfer between vehicles.

Soviet spacecraft Soyuz 4 and Soyuz 5 docked in orbit, achieving the first-ever linkup of two crewed vehicles and briefly forming an experimental space station.

Apollo 9 astronauts splashed down in the Atlantic after ten days testing the lunar module in Earth orbit, a critical rehearsal for the Moon landing.

Apollo 10 launches from Kennedy Space Center, sending astronauts to lunar orbit for a full dress rehearsal of the moon landing, nicknamed with call signs Charlie Brown and Snoopy.

Astronauts Thomas Stafford and Eugene Cernan flew the lunar module 'Snoopy' to within 15.6 kilometers of the moon's surface in a full dress rehearsal for the landing.

Apollo 10 splashed down in the Pacific after a dress-rehearsal mission that tested every part of a lunar landing except the landing itself.

Neil Armstrong, Buzz Aldrin, and Michael Collins entered pre-launch isolation to avoid infection just days before humanity's first crewed Moon landing mission.

The Soviet Union launched Luna 15, an uncrewed probe racing to scoop lunar soil and return it to Earth before America's Apollo 11 astronauts could plant their flag.

A Saturn V rocket carrying Neil Armstrong, Buzz Aldrin, and Michael Collins lifted off from Cape Kennedy toward the moon.

One day after launch, Apollo 11's crew performed a routine mid-course correction burn as their spacecraft sped toward a historic lunar landing.

Apollo 11 sped toward the Moon, with astronauts making a televised broadcast and correcting course as anticipation built worldwide.

Apollo 11 fired its service propulsion engine and slipped into orbit around the Moon, putting Armstrong, Aldrin, and Collins one day from humanity's first landing.

Neil Armstrong and Buzz Aldrin touched down the Apollo 11 lunar module Eagle in the Sea of Tranquility, with just seconds of fuel remaining.

Neil Armstrong stepped onto the lunar surface, telling 600 million television viewers 'that's one small step for man, one giant leap for mankind.'

Astronauts aboard Apollo 11 held their final in-flight press conference as their capsule sped back toward Earth after the first Moon landing.

Apollo 11's command module splashed down in the Pacific Ocean, completing humanity's first successful crewed mission to land on the Moon.

Soviet cosmonauts achieved the first docking of two crewed spacecraft, transferring crew members between vessels via spacewalk in orbit.

The Soviet Union launched Venera 7, which would become the first spacecraft to successfully transmit data after landing on another planet.

The Soviet Union's Lunokhod 1, the first remote-controlled rover to explore another world, begins its mission on the lunar surface.

Apollo 13 lifts off from Kennedy Space Center bound for the Moon, unaware a damaged oxygen tank will nearly doom the crew days later.

An oxygen tank ruptured aboard Apollo 13 en route to the Moon, forcing astronauts to abandon their lunar landing and fight for survival using the lunar module as a lifeboat.

An oxygen tank ruptured aboard Apollo 13 en route to the Moon, crippling the spacecraft and forcing astronauts into a desperate fight for survival.

Two days after an oxygen tank explosion crippled Apollo 13, NASA and the crew executed a critical free-return trajectory burn to slingshot around the Moon toward Earth.

Apollo 13's crew safely returned to Earth, splashing down in the Pacific after a harrowing four-day fight for survival following an oxygen tank explosion.

Astronauts Lovell, Swigert, and Haise splashed down safely in the Pacific, capping a harrowing mission after an oxygen tank explosion crippled their spacecraft.

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NASA's Mariner 9 spacecraft performs a critical mid-course correction burn en route to Mars, refining its trajectory ahead of orbital insertion.

NASA formally confirms the Apollo 14 crew—Alan Shepard, Stuart Roosa, and Edgar Mitchell—ahead of the mission's late-January launch to the lunar highlands.

NASA's Apollo program continued advancing toward its third lunar landing, part of a broader thaw that would soon lead to unprecedented US-Soviet cooperation in orbit.

NASA launched Apollo 14 from Kennedy Space Center, sending Alan Shepard—America's first man in space—on a mission that would make him the fifth person to walk on the Moon.

NASA and the Soviet Academy of Sciences held early talks that would eventually lead to the joint Apollo–Soyuz Test Project, the first cooperative U.S.–Soviet space mission.

Apollo 14 launched from Kennedy Space Center carrying Alan Shepard, who would become the fifth and oldest man to walk on the Moon.

Apollo 14 commander Alan Shepard struck two golf balls with a makeshift club during the mission's final moonwalk, the first sporting shot played off-Earth.

Apollo 14 splashed down in the Pacific, completing NASA's third successful crewed lunar landing after the Apollo 13 near-disaster.

The Soviet Union launched Mars 2, sending an orbiter and lander toward the Red Planet in a bid to beat NASA to a successful Martian landing.

Apollo 15 astronauts David Scott and James Irwin landed on the Moon's Hadley-Apennine region, bringing along the first lunar rover ever driven off Earth.

Apollo 17's lunar module touched down in the Taurus-Littrow valley, beginning the final crewed Moon landing of the 20th century.

Apollo 17's crew, the final humans to walk on the Moon, splashed down as America's lunar program drew to a close.

Apollo 17 lit up the Florida night sky at 12:33 a.m., the only crewed Saturn V launched after dark, carrying the last men to walk the Moon.

NASA's final crewed lunar mission lifted off at night from Kennedy Space Centre, carrying the last astronauts to walk on the Moon.

Apollo 17's lunar module Challenger touched down in the Taurus-Littrow valley, beginning humanity's final crewed visit to the lunar surface.

Apollo 17 astronauts Eugene Cernan and Harrison Schmitt lifted off from the lunar surface, the last humans to walk on the Moon to this day.

Actually correcting: Apollo 17 splashed down on December 19, 1972; entry replaced with an accurate December 15 space event.

Days after splashdown, Apollo 17's crew — the last humans to walk on the Moon — returned to a wave of ceremonies closing out NASA's lunar landing program.

Apollo 17's lunar module Challenger touches down in the Taurus-Littrow valley, beginning the last crewed mission to walk on the Moon.

Apollo 17 splashed down in the Pacific, closing out NASA's lunar landing program with astronauts Cernan and Schmitt having spent 75 hours on the Moon's surface.

American and Soviet officials signed the agreement establishing the Apollo-Soyuz Test Project, the first joint crewed space mission between Cold War rivals.

NASA prepared Pioneer 10 for launch on a mission that would make it the first spacecraft to traverse the asteroid belt and fly past Jupiter.

The Soviet Union launched Venera 8 toward Venus, part of a pioneering series of probes that would achieve the first successful landing on another planet's surface.

Astronauts John Young and Charles Duke landed the Lunar Module Orion in the lunar highlands, beginning the fifth crewed Moon landing.

Astronauts John Young, Charlie Duke, and Ken Mattingly returned safely to Earth after exploring the lunar highlands with a rover.

American and Soviet officials signed an agreement paving the way for the 1975 Apollo-Soyuz Test Project, the first joint crewed spaceflight between the two Cold War rivals.

Weeks after their lunar landing, Apollo 16 crew members John Young and Charles Duke completed final mission debriefings, cementing data from their record lunar rover drives.

The U.S. and Soviet Union signed an agreement paving the way for the 1975 Apollo-Soyuz Test Project, the first joint superpower spaceflight of the Cold War.

Nixon administration officials and Soviet counterparts signed the formal agreement for the Apollo-Soyuz Test Project, the first joint US-Soviet crewed space mission.

NASA launched Skylab 4, sending three astronauts on the longest American spaceflight to date, an 84-day mission plagued by a famous crew strike.

NASA launched Skylab 4, sending three astronauts on an 84-day mission that would become the longest American spaceflight of its era.

NASA launched Skylab 4, sending three astronauts on what became, at the time, the longest human spaceflight in history at 84 days.

Astronauts Gerald Carr, William Pogue, and Edward Gibson returned to Earth after an 84-day mission, then the longest spaceflight in history.

NASA launched Skylab, America's first space station, atop a Saturn V rocket, only to discover it had lost a meteoroid shield and one solar panel during ascent.

NASA launched Skylab, America's first space station, atop a modified Saturn V rocket from Cape Kennedy, but damage during ascent nearly doomed the mission.

American and Soviet space officials finalized technical protocols in Moscow for the Apollo-Soyuz Test Project, the first joint US-Soviet human spaceflight.

NASA's Mariner 10 probe makes its historic first flyby of Mercury, returning humanity's first close-up images of the solar system's innermost planet.

NASA's Mariner 10 became the first spacecraft to fly past Venus en route to Mercury, using the planet's gravity to bend its trajectory.

NASA's Skylab 4 astronauts returned to Earth after 84 days in orbit, then the longest spaceflight in history, having staged a one-day strike over their grueling schedule.

The Soviet probe Venera 9 transmitted the first images ever taken from the surface of another planet, revealing a rocky, sunlit Venusian landscape.

NASA's Mariner 10 completed its third and final flyby of Mercury, capturing the last images before running out of fuel, having become the first probe to visit the planet.

American and Soviet spacecraft docked in orbit for the first time, a symbolic handshake in space marking a thaw in Cold War rivalry.

The Soviet Venera 9 spacecraft, launched this week, was en route to Venus, where it would later transmit the first images from the surface of another planet.

Soviet cosmonauts Pyotr Klimuk and Vitaly Sevastyanov docked Soyuz 18 with the Salyut 4 space station, beginning a 63-day mission of scientific observation.

An American Apollo capsule and Soviet Soyuz spacecraft launched hours apart, beginning the first joint US-Soviet space mission and a symbolic thaw in the Cold War space race.

American and Soviet spacecraft docked in orbit, and astronaut Tom Stafford clasped hands with cosmonaut Alexei Leonov through the open hatch.

NASA launched Voyager 2 from Cape Canaveral, sending it on a grand tour past Jupiter, Saturn, Uranus, and Neptune.

NASA launched Voyager 1 aboard a Titan-Centaur rocket, beginning a grand tour of the outer planets that would make it the most distant human-made object in space.

NASA's Voyager 1 spacecraft, weeks after launch, photographed Earth and the Moon together in a single frame for the first time from deep space.

NASA's Voyager 2 spacecraft, launched days earlier and now on its way, was checked into deep space cruise mode as engineers monitored its Grand Tour trajectory toward Jupiter.

NASA announced its astronaut class of 1978, including Sally Ride, who five years later became the first American woman in space.

Astronomer James Christy spotted a bulge on photographic plates of Pluto, revealing the dwarf planet's largest moon, Charon.

NASA's Voyager 1 spacecraft, closing in on Jupiter, transmits striking new images revealing details of the planet's turbulent atmosphere and moons.

Voyager 1 images reveal an active volcanic plume erupting from Jupiter's moon Io, the first volcanic eruption ever observed on another world.

NASA's Voyager 1 spacecraft, en route to its historic encounter with Jupiter, continued transmitting striking new imagery of the giant planet's turbulent atmosphere.

NASA's Voyager 1 spacecraft, deep into its Jupiter flyby aftermath, continues transmitting revelatory close-up images of the volcanic moon Io back to Earth.

NASA's abandoned Skylab space station tumbled out of orbit and disintegrated over the Indian Ocean and Western Australia, scattering debris across the outback.

NASA's abandoned space station Skylab plunged through the atmosphere and scattered debris across the Indian Ocean and Western Australia.

Weeks after NASA's Skylab space station tumbled uncontrolled into the atmosphere and scattered debris over Australia, officials continued assessing the fallout from America's first space station's dramatic demise.

Columbia lifted off from Kennedy Space Center on STS-1, the first flight of NASA's reusable Space Shuttle program, crewed by John Young and Robert Crippen.

NASA's Pioneer 10 probe passed beyond the orbit of Neptune, becoming the first human-made object to leave the known planetary boundary of the solar system.

Sally Ride became the first American woman in space aboard Space Shuttle Challenger's STS-7 mission, launching from Kennedy Space Center.

Svetlana Savitskaya became the first woman to perform a spacewalk, working outside the Salyut 7 space station for over three hours.

Cosmonauts Vladimir Dzhanibekov and Viktor Savinykh dock with the derelict, frozen Salyut 7 station and revive it from total electrical failure in a daring salvage mission.

NASA's Voyager 2 spacecraft made its closest approach to Uranus, the only close-up visit to the planet ever conducted, revealing rings, moons, and a tilted magnetic field.

A day after the Challenger disaster, Americans held vigils and NASA began the grim work of recovery as investigators started piecing together what went wrong.

NASA delayed the Challenger shuttle launch by a day due to a stuck bolt and weather concerns, pushing the fateful liftoff to January 28.

The Space Shuttle Challenger broke apart 73 seconds after launch, killing all seven astronauts including teacher Christa McAuliffe.

The Rogers Commission held its first public hearing into the Space Shuttle Challenger disaster, beginning the inquiry that exposed NASA's O-ring failures.

Physicist Richard Feynman is sworn into the Rogers Commission investigating the Challenger disaster, where his ice-water O-ring test would become iconic.

Soyuz TM-3 landed safely, returning cosmonauts including Muhammed Faris, the first Syrian and one of the earliest Arab citizens in space.

The Soviet space shuttle Buran launches unmanned, orbits Earth twice, and lands automatically—its only flight before the program's cancellation.

Soviet Soyuz TM-7 carrying French astronaut Jean-Loup Chrétien docked with the Mir space station, deepening Cold War-era space cooperation.

Aboard the Mir space station, cosmonauts continued a research mission studying long-duration spaceflight effects, part of the growing Soviet effort to master orbital endurance.

NASA's Voyager 2 probe, deep in its historic approach to Neptune, beamed back increasingly detailed images as it prepared for its closest flyby later that month.

NASA's Voyager 2 probe closed in on Neptune, beaming back the sharpest images yet seen of the solar system's outermost giant planet just days before its historic flyby.

NASA's Voyager 2 made its closest approach to Neptune, becoming the only spacecraft ever to visit the ice giant and revealing its Great Dark Spot and rings.

NASA's Voyager 2 made its closest approach to Neptune, the only spacecraft ever to visit the solar system's farthest major planet.

NASA's Voyager 2 probe made its closest approach to Neptune, the last planet on its grand tour, revealing the Great Dark Spot and the moon Triton's icy geysers.

NASA's Voyager 2 made its closest approach to Neptune, the only spacecraft ever to visit the giant blue planet, revealing its Great Dark Spot and moon Triton.

NASA's Voyager 2 made its closest approach to Neptune, the only spacecraft ever to visit the giant blue planet, revealing its Great Dark Spot and moon Triton.

Space Shuttle Atlantis deployed the Magellan probe, sending it on a journey to map the surface of Venus with radar through its thick clouds.

NASA's Voyager 1 spacecraft, at the urging of astronomer Carl Sagan, turned its camera around from 3.7 billion miles away to photograph Earth as a tiny speck of light.

Space Shuttle Discovery launched on mission STS-36, carrying a classified Department of Defense payload into orbit.

Soviet cosmonauts Anatoly Solovyev and Alexander Balandin docked Soyuz TM-9 with the Mir space station to begin a long-duration mission.

Space Shuttle Discovery carries the Hubble Space Telescope into orbit, beginning a mission that would transform humanity's view of the cosmos.

Space Shuttle Discovery deployed the Hubble Space Telescope into low Earth orbit, beginning a mission that would transform humanity's view of the universe.

NASA released the Hubble Space Telescope's first images to the public, revealing sharper views of star clusters than any ground telescope could achieve.

Space Shuttle Endeavour launched on its first mission, STS-49, on May 7, 1992, but its crew's dramatic satellite rescue spacewalk actually began capturing headlines days earlier.

Space Shuttle Endeavour launched on its maiden voyage, STS-49, to rescue and repair a stranded communications satellite in the first three-person spacewalk.

Soyuz TM-17 launched carrying a French-Russian crew to the Mir space station, part of the growing cooperative spaceflight programs of the post-Soviet era.

Cosmonauts aboard the Mir space station conducted a lengthy spacewalk to repair exterior damage, part of the ongoing effort to keep the aging Russian outpost operational.

Cosmonaut Valeri Polyakov returned to Earth aboard Soyuz TM-20 after 437 days aboard Mir, still the longest single human spaceflight in history.

Space Shuttle Atlantis docked with Russia's Mir space station, the first shuttle-Mir linkup and largest spacecraft ever assembled in orbit at the time.

NASA launched the Mars Global Surveyor toward the Red Planet, beginning a mission that would map Mars in unprecedented detail for nearly a decade.

NASA launched the Mars Pathfinder mission, carrying the small rover Sojourner, which would become the first wheeled vehicle to operate on another planet.

NASA launched Mars Pathfinder atop a Delta II rocket, sending a lander and the microwave-oven-sized rover Sojourner toward the Red Planet.

NASA's Galileo spacecraft made its first close flyby of Jupiter's icy moon Europa, capturing detailed images hinting at a subsurface ocean beneath its cracked, frozen crust.

NASA launched the Cassini-Huygens spacecraft from Cape Canaveral on a seven-year journey to study Saturn and its moon Titan.

A Russian Proton rocket launched the Zarya module from Baikonur Cosmodrome, the first component of the International Space Station, beginning humanity's largest cooperative space project.

NASA's Chandra X-ray Observatory, launched days earlier aboard shuttle Columbia, reached its final elongated orbit, becoming the most powerful X-ray telescope ever built.

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Space Shuttle Columbia disintegrated over Texas during re-entry, killing all seven astronauts, after foam debris had damaged its wing at launch.

The British Beagle 2 lander, which vanished after reaching Mars on Christmas Day 2003, was officially declared lost by the European Space Agency.

SpaceShipOne, piloted by Mike Melvill, became the first privately funded crewed spacecraft to reach space, soaring past the 100-kilometer boundary.

Astronomers using the Hubble Space Telescope announced the discovery of two new moons orbiting Pluto, later named Nix and Hydra.

NASA's Cassini spacecraft made a close flyby of Saturn's moon Titan, gathering radar data that revealed hints of hydrocarbon lakes beneath its thick orange haze.

NASA's Chandra X-ray Observatory released a stunning composite image capturing the Crab Nebula pulsar unleashing jets of matter and antimatter.

Space shuttle Discovery, carrying Japan's Kibo laboratory module, docked with the International Space Station, delivering the largest single module ever added to the outpost.

NASA's MESSENGER spacecraft completed its primary mapping mission of Mercury, delivering the first complete portrait of the innermost planet.

NASA's MESSENGER spacecraft, orbiting Mercury, transmits data revealing the planet's surprising volcanic history and unusual magnetic field structure.

A Soyuz spacecraft carrying a fresh crew docked with the International Space Station, part of the routine but perilous choreography keeping humans permanently in orbit.

Space Shuttle Atlantis launched on STS-135, the final flight of NASA's 30-year Space Shuttle program, from Kennedy Space Center.

NASA launched the MAVEN spacecraft from Cape Canaveral to study how Mars lost its atmosphere and much of the water once believed to have covered its surface.

China launched the Chuangxin-3 and Shiyan-7 satellites along with Shijian-15 aboard a Long March rocket from Jiuquan, expanding its growing satellite constellation.

The European Space Agency's Philae probe makes the first-ever soft landing on a comet, touching down on 67P/Churyumov-Gerasimenko after a ten-year journey.

China conducts a key milestone test toward reusable rocket technology as its commercial space sector accelerates development to rival SpaceX.

A Soyuz MS-12 rocket launched cosmonaut Alexey Ovchinin, astronaut Nick Hague, and astronaut Christina Koch to the International Space Station.

A Cygnus cargo craft launched to the ISS carried RWASAT-1, part of a wave of small nanosatellites developed by African nations expanding into space technology.

Soyuz MS-18 landed in Kazakhstan carrying back actress Yulia Peresild and director Klim Shipenko, who had filmed the first movie scenes ever shot in orbit.