15 years ago this week, the International Space Station accommodated its first crew members. Now, 180 months later, the orbiting outpost has not been uncrewed since, playing host to over 220 astronauts, cosmonauts and fee-paying space tourists.
Here are just a few of the highs and lows of humanity's most ambitious international endeavor in space.
PHOTOS: 'Space Invader' Found on International Space Station
The space station awaiting NASA astronaut William Shepherd, center, and cosmonauts Yuri Gidzenko, left, and Sergei Krikalev, right, 15 years ago wasn’t the first outpost to orbit Earth, nor the first to host residents from the United States and its former Cold War foe, Russia. But unlike NASA’s 1970s-era Skylab and the series of Soviet stations that ended in 2001 with Mir, the International Space Station, or ISS, was a joint program from the get-go.PHOTOS: Meet the Space Station's Resupply Fleet
Assembly began on Nov. 20, 1998 with Russia launching the Zarya control module, pictured here in the center with the shorter solar panel wings. Three space shuttle missions followed to install the Unity connecting node (located at the bottom in this image), deliver supplies and prepare the station for the arrival of the Russian-launched Zvezda service module, at top, with a Russian Progress cargo ship attached. Two more space shuttle missions followed with more equipment and supplies before the first station crew blasted off aboard a Russian Soyuz rocket on Oct. 31, 2000. The crew arrived at the station two days later to begin a 4.5 month-long mission.PHOTO: Enormous Red Sprites Seen From Space
The first station crew, known as Expedition One, hosted two visiting crews of space shuttle astronauts and added the U.S. Destiny laboratory module to the growing outpost before their replacements arrived aboard another space shuttle mission on March 10, 2001. That handover marked the first in an unbroken string of crew rotations that have kept the station permanently staffed for 15 years. The current station crew, led by NASA astronaut Scott Kelly, is Expedition 45.PHOTOS: Space Station Astronauts Log One Million Photos
During their 167-day flight, the Expedition Two crew, comprised of Russian cosmonaut Yury Usachev and NASA astronauts Susan Helms and James Voss, became de facto space ambassadors when Russia insisted on flying a privately paying tourist. NASA vehemently objected to Dennis Tito, an American businessman, flying with the Russian taxi crew delivering a fresh Soyuz capsule to the station. NASA said it was too early in the station’s ongoing development for non-professional astronauts, but in the end, Russia, which was charging Tito some $20 million for the trip, prevailed. Tito, left in above image, spent six days aboard the station. Since then, six other passengers have paid upwards of $40 million to visit the station. One tourist, Microsoft co-founder Charles Simonyi, flew twice.PHOTOS: Urban Planning: Cities Seen From Space
Station assembly continued at a steady pace until Feb. 1, 2003, when shuttle Columbia, on a rare, non-space station research flight, broke apart during its return to Earth, killing seven astronauts. Shuttle flights were immediately suspended, shifting sole responsibility for keeping the station staffed to Russia. The shuttle returned to flight in July 2005, but was grounded again for another year for more modifications. The STS-107 Columbia crew, left to right from top, David Brown, pilot William McCool, payload commander Michael Anderson, Kalpana Chawla, commander Rick Husband, Laurel Clark and Israeli astronaut Ilan Ramon.PHOTOS: Epic Aurora Photos From the Space Station
Heeding the advice of the Columbia accident investigation board, NASA decided to retire its remaining three space shuttles once construction of the space station was finished. After 21 post-Columbia shuttle missions to the station, plus one last servicing call to the Hubble Space Telescope, NASA grounded the fleet. Shuttle Atlantis, pictured above, completed the last flight on July 21, 2011. On the second to last mission, sister ship Endeavour delivered the station’s premier science experiment, a multi-national $2 billion particle detector known as the Alpha Magnetic Spectrometer. With the shuttles out of service, NASA again was dependent on Russia to fly crews to the station.PHOTOS: Inside Atlantis' Final Space Station Mission
As part of its post-shuttle planning, NASA embarked on a controversial, cost-cutting program to purchase flight services, rather than build and operate its own spaceships, for transportation to and from the station. Ultimately, two companies, Space Exploration Technologies, or SpaceX, and Orbital Sciences, which has since merged with another firm and is now known as Orbital ATK, began making cargo runs to the station. SpaceX got there first, with a test run in May 2012, pictured above. Astronauts aboard the station use a robotic arm to snare the capsule from orbit and berth it to the station. NASA also has given launch contracts and financial support to SpaceX and Boeing to fly station crew as well.PHOTOS: Meet the Space Station's Resupply Fleet
With two new supply lines to the station, NASA was happily back making cargo runs to the station until launch accidents temporarily grounded both firms. Pictured above, an Orbital Antares rocket, carrying a Cygnus cargo ship, exploded minutes after liftoff from the Mid-Atlantic Regional Spaceport on Wallops Island, Virginia, on Oct. 28, 2014. The company plans to resume flights on a new version of Antares in 2016. Meanwhile, Orbital has purchased two rides for Cygnus capsules on United Launch Alliance Atlas rockets. SpaceX, which also flies commercial satellites on its Falcon 9 rockets, had a launch accident on June 28, 2015, during its seventh resupply run to the station. SpaceX is planning to resume flights in December, though its next station cargo flight is not expected until January at the earliest.PHOTOS: 'Space Invader' Found on International Space Station
Despite launch accidents, political turmoil and financial concerns, the 15-nation station partnership has endured and become a model for future international programs to send astronauts and cosmonauts farther into space. In March, NASA and Russia began the first of what is expected to be series of year-long missions in an attempt to learn more about how spaceflight impacts the human body and mind. NASA astronaut Scott Kelly, pictured above, and Russian cosmonaut Mikhail Kornienko are serving as the first subjects, work that scientists hope will pave the way for three-year missions to Mars.PHOTOS: Inside the First 100 Days of a Year in Space
Thirty years ago, the Soviet Union launched the core module for the space station Mir. Mir was the first modular space station assembled in orbit, finally completed in 1996. The spacecraft tripled its expected five-year lifespan, operating for more than 15 years, and even outlived the U.S.S.R.
During its time in orbit, Mir had a checkered history, both a pioneer for its many breakthroughs but also a problem child, with a history of power failures, trash buildup, hygiene concerns, a fire and an in-orbit collision. Even with its achievements now eclipsed by the International Space Station (ISS), the Mir still set an important precedent for international cooperation and made invaluable contributions to the science of space travel.
The name “Mir” translates to “world” or “peace” in English. In its original use, the word “Mir” represents a village, a traditional community “with common goals and values in a place where they had a better chance of surviving, living a productive life, and succeeding as a group,” former director of the Shuttle-Mir program Frank L. Culbertson, Jr. recounted in 1996.
That sense of cooperation appropriately characterized life on the space station. Although Mir was a Russian space station, it hosted more than 100 space travelers from a dozen countries around the world, including France, Germany, Japan and even Afghanistan.
American astronauts first arrived on Mir nearly a decade into its life. The post-Soviet collapse had left both the American and Russian space programs in jeopardy, as the Americans lost their main competitor in the space race and the Russians suffered economic collapse. In order for NASA and Roscosmos, the successor to the Soviet space program, to salvage their own separate plans for next-generation space stations, the two had to work together to focus their efforts on a collaborative project.
“Phase One” of the cooperation between the United States and Russia was the Shuttle-Mir program, which brought both astronauts and cosmonauts on board the space shuttle for several missions to Mir and back. “Phase Two” was the construction of the ISS itself.
Mir brought together in space what were rival nations on Earth. It also provided an invaluable window into the potential for long-duration spaceflight.
The space station set a number of records for time spent in space. Cosmonaut Valeri Polyakov in 1995 achieved a record 437 days, 17 hours and 38 minutes for a continuous-orbit stay aboard Mir. A year later, astronaut Sharon Lucid set the endurance record for women with 188 days and 4 hours in orbit. Their experiences provided a window into the physiological and psychological effects of extended space missions.
Mir also hosted experiments aimed at sustaining life in space. The station raised wheat, the first crop to be grown from seed to seed in outer space. So if humans ever do find a need to grow, say, potatoes on another planet, space travelers will have Mir to thank.
On March 23, 2001, Mir met its end when Russia’s space agency allowed the station to deorbit, leading the 134-ton structure to break up and crash over the Pacific Ocean. The space station may be in pieces at the bottom of the sea, but its legacy, which lives on in the ISS and future space stations yet to come, remains intact.