Editors' note: This is part of a series examining 50 years of space exploration.
In the 50 years since Sputnik's launch, there have been numerous advances and setbacks, as humans endeavor to learn more about the universe around them. Here is a look at some of the key events that brought humans into space and brought home valuable information that will guide where we go next.
October 4, 1957--Soviet Union launches Sputnik I.
November 3, 1957--Sputnik II launches, with ill-fated Laika the dog on board.
January 31, 1958--United States launches Explorer I from Cape Canaveral in Florida.
October 1, 1958--NASA is formed after Congress passes the National Aeronautics and Space Act.
April 12, 1961--Cosmonaut Yuri Gagarin becomes the first human to enter space and return safely.
May 5, 1961--With the launch of Freedom 7, Alan Shepard becomes the first American man in space. The suborbital flight, which was part of the Mercury Project, lasted 15 minutes, 28 seconds.
May 25, 1961--U.S. President John F. Kennedy announces the goal of sending astronauts to the moon before the end of the decade.
February 20, 1962--Launch of Friendship 7 (also part of the Mercury Project) makes astronaut John Glenn the first American to go into orbit. Total flight time was just shy of five hours.
August 21, 1965--Launch of Gemini 5, carrying astronauts Gordon Cooper and Charles Conrad on an eight-day mission to test rendezvous guidance and navigation systems, as well as study how humans could handle long-term exposure to a space environment. Gemini would be the critical link between the early Mercury Project and the Apollo missions.
January 27, 1967--Mission AS-204 is struck by tragedy when a flash fire breaks out during a launch pad test, killing three astronauts: Virgil Grissom, who had participated in Mercury and Gemini flights; Edward White, who conducted NASA's first extravehicular activity; and new astronaut Roger Chaffee. The mission, one of NASA's first major setbacks, was later renamed Apollo 1.
November 9, 1967--First test flight of the Saturn V rocket, which would carry dozens of spacecraft into space in the years to come
July 16, 1969--Launch of Apollo 11
July 20, 1969--Astronauts Edwin "Buzz" Aldrin and Neil Armstrong become the first men to walk on the moon.
March 2, 1972--Launch of unmanned Pioneer 10: Earth's first space probe to an outer planet, the first spacecraft to travel through the asteroid belt, the first spacecraft to make direct observations and obtain close-up images of Jupiter, and the first man-made object to leave the solar system. Pioneer 10 sent its last communication back to Earth on January 22, 2003, while 7.6 billion miles from home.
May 14, 1973--United States launches its first experimental space station, the Skylab.
July 15, 1975--Apollo-Soyuz Test Project is the first international manned space flight to test out cooperated space rescue and docking.
August 20, 1975--Launch of Viking 1, the first orbiter and lander sent to Mars. Viking 2 would launch a few weeks later. Both landed safely on Mars and for six years sent back the first set of images and data from the Martian surface.
August 20, 1977--Launch of Voyager 2, one of a pair of spacecraft sent by NASA on what was supposed to be a five-year mission to study Jupiter and Saturn. Voyagers 1 and 2 continue to send back pictures and data today, 30 years later from nearly 10 billion miles away.
September 5, 1977--Launch of Voyager 1
May 20, 1978--Launch of the first of two spacecraft called Pioneer Venus, which would study the Venusian atmosphere.
April 12, 1981--Aboard the space shuttle Columbia, Robert L. Crippen and John W. Young make the first mission in NASA's space shuttle program.
June 18, 1983--Sally Ride becomes first American woman in space with launch of shuttle mission STS-7 aboard the space shuttle Challenger.
August 30, 1983--Guion S. Bluford, Jr., becomes first black man in space with launch of shuttle mission STS-8 aboard the space shuttle Challenger.
January 28, 1986--First major catastrophe for NASA, when space shuttle Challenger (mission STS-51L) explodes 73 seconds after takeoff with seven crewmembers aboard
February 19, 1986--Mir space station launches.
October 18, 1989--Space shuttle Atlantis launches Galileo to study Jupiter and its moons. It took Galileo six years to reach Jupiter, and it finally disintegrated in Jupiter's atmosphere in September of 2003, 14 years after it began its collision course toward the giant planet.
February 3-11, 1994--Cosmonaut Sergei Krikalev becomes the first Russian to fly aboard a U.S. space shuttle.
March 14, 1995--Astronaut Norman Thagard launched with Cosmonauts Vladimir Dezhurov and Gennady Strekalov aboard a Russian Soyuz to spend 115 days on Mir.
December 4, 1996--Launch of Mars Pathfinder
July 4, 1997--Pathfinder lands on Mars. The rover Sojourner would go on to explore the Martian surface for more than 80 days.
November 20, 1998--First piece of the International Space Station is launched.
November 2, 2000--The crew of Expedition One, astronaut Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev, dock at the International Space Station. They are the first people to take up residence at the ISS, staying there for several months.
August 8, 2001--Launch of Genesis, which would collect samples of atoms from solar wind. Genesis would be the first attempt to return samples to Earth since the Apollo moon mission in 1972.
February 1, 2003--Crew of seven astronauts, including the first Israeli astronaut, is lost after a 16-day mission when the Columbia space shuttle explodes on re-entry. The accident was later attributed to damage sustained to foam insulation and has led NASA to understand how to safely repair similar damage on later missions.
June 10 and July 7, 2003--Mars Exploration Rovers Spirit and Opportunity launch.
January 2004--Spirit and Opportunity arrive on the Martian surface. They continue to explore the Red Planet today.
September 8, 2004--After capturing particles from the sun, Genesis makes a dramatic crash landing in Utah when its parachute fails to deploy. Despite the landing, scientists still managed to recover and study the samples.
September 30, 2004--SpaceShipOne becomes the first privately built craft to reach outer space.
August 4, 2007--Phoenix lander launches on its way to explore the northern pole of Mars.
Day 1: Private industry moves to take over space race
The space race taking shape in the private sector today is due in large part to boyhood dreams of becoming astronauts.
Day 1: Space entrepreneur shoots for the moon
Space Adventures CEO Peter Diamandis talks about the future of private space travel to the moon and beyond.
Day 1: Key milestones in space exploration
A timeline of some of the events that brought humans into space and will guide where we go next.
Day 2: Silicon galaxy
Technologies developed by NASA have led to some of the most important commercial innovations to come out of Silicon Valley.
Day 2: The satellite age
The commercial satellite market has grown into a multibillion-dollar industry, but future growth could suffer.
Day 3: Do we need NASA?
Is NASA still worth spending more than $16 billion in taxpayer money each year?
Day 3: Designing a 21st-century space suit
MIT professor Dava Newman tells how the form-fitting BioSuit will help give NASA a ready-to-wear outfit for the moon and Mars.
Memories from the space age
CNET News.com readers (and writers) share their memories from the early days of space exploration. October 5, 2007
Japan probe approaches moon
A new space race is getting under way, with as many as five nations expecting to land hardware on the moon within five years. October 4, 2007
Who's who in space travel
The private sector is laying the groundwork for a new era of space exploration. October 3, 2007
A half-century of space flight
We take a look at how the ships that enable space exploration are evolving. October 1, 2007
Strange visitors to other planets
The first Voyager spacecraft left Earth 30 years ago. Now, nearly 10 billion miles from home, they aren't finished yet.August 28, 2007
Building a better space suit
At MIT and the University of North Dakota, researchers are trying out new designs to clothe astronauts heading to Mars. July 18, 2007
Stellar views from the Hubble at 17
NASA and ESA celebrate the Hubble Space Telescope's anniversary with colliding stars and supernovas.April 25, 2007
The race to space: Recalling Sputnik
The Baltimore Sun
Science Times special coverage
New York Times
The next 50 years in space
Happy birthday, Sputnik! (Thanks for the Internet)
Thank Sputnik for today's orbital freedom
Christian Science Monitor
Editors: Jennifer Guevin, Jim Kerstetter
Design: Andrew Ballagh
Production: Madeleine Kempton