The International Space Station (ISS) is a multi-nation construction project that is the largest single structure humans have ever put into space. This high-tech research laboratory orbits approximately 250 miles above Earth. Since the first components were launched in 1998, the station has been continuously occupied by rotating crews of astronauts and cosmonauts since November 2000. The ISS was built by NASA, Roscosmos (Russia), the European Space Agency, JAXA (Japan) and CSA (Canada) and represents the culmination of scientific and engineering knowledge gained from decades of space research and exploration.
Purpose and Goals
The main goals of the ISS are to develop technologies required for the exploration of deep space and to conduct scientific research that can only be done in microgravity. NASA views the ISS as a vital stepping stone to future human exploration beyond low Earth orbit, including missions to the Moon and Mars.
Some key research goals and benefits of the ISS include:
- Understanding the long-term effects of microgravity on human health to enable safe long-duration spaceflight
- Testing technologies like life support systems and spacecraft materials needed for deep space missions
- Conducting research across diverse fields including medicine, biology, physics, astronomy and meteorology
- Inspiring students to pursue careers in STEM fields
- Fostering international cooperation in space exploration across 21 nations
Major Components
The ISS is composed of pressurized modules, external trusses, solar arrays and other components built in orbit. Major ISS components include:
- Zarya: The first module launched in 1998, provides battery power and propulsion.
- Unity: A connecting module with six berthing locations.
- Zvezda: Provides living quarters, life support, electrical power distribution, data processing, flight control systems and propulsion systems.
- Destiny: The primary research laboratory module.
- Canadarm2: A robotic arm built by Canada used to maintain the station.
- Kibo: Japan’s primary research module with a robotic arm.
- Columbus: The European laboratory module.
- Cupola: An observatory module with windows for viewing Earth and docking spacecraft.
Assembly Timeline
The ISS was assembled piece by piece in orbit by astronauts during complex spacewalks spanning several years. Some key milestones include:
- November 1998: The first module, Zarya, was launched by Russia.
- December 1998: The Unity module was launched by the US and connected to Zarya.
- July 2000: The Zvezda service module was added, allowing a permanent crew.
- February 2001: The Destiny lab module was delivered by the US.
- October 2007: Harmony connecting node added along with the first starboard truss segment.
- February 2008: Columbus
- 2008 and 2009: Kibo
- March 2009: Solar array wings expanded to full length.
- February 2010: Tranquility node and Cupola observatory installed.
- May 2011: The final major US component, the Alpha Magnetic Spectrometer, was added.
- July 2021: Nauka
- 2021 to 2025: iROSEs solar panels
Current Operations
Source: NASA
The completed ISS has been continuously occupied by rotating international crews since November 2000. Currently in its third decade of operations, some key facts about ongoing ISS activities include:
- Crew size expanded from 3 to 6 members in 2009 to maximize research
- Over 3,000 research investigations conducted in microgravity
- More than 3 million students per year participate in ISS education programs
- Crew members spend 35+ hours per week conducting research
- More than 273 astronauts from 21 countries have visited the ISS
- Real-time operational control from Mission Control centers in Houston and Moscow
- Resupply missions visit the ISS every few months to deliver science experiments, crew provisions, maintenance parts and more
Future Plans
While the partners initially agreed to fund the ISS until 2024, operations have now been extended to at least 2030. Some key items planned for the ISS’s remaining years include:
- Expand commercial activities like space tourism and private astronaut missions
- Test technologies needed for the Lunar Gateway, a small space station orbiting the Moon
- Increase commercial use of station facilities for research and manufacturing
- Continue cutting-edge scientific research across fields from plant growth to particle physics
- Prepare for transition to commercial space stations in low Earth orbit after ISS retirement
The ISS has proven to be an invaluable asset for advancing space exploration. As humanity continues to reach farther into space, the station’s legacy of international cooperation, scientific discovery and technological innovation will live on.
