The International Space Station (ISS) has been a monumental achievement in global collaboration, maintaining a continuous human presence in Low Earth Orbit (LEO) since 2000. This orbiting laboratory has facilitated groundbreaking microgravity research, providing data that benefits Earth and prepares humanity for deep space missions. However, the ISS is an aging structure with rising maintenance costs, and its operational life is scheduled to conclude with a controlled deorbit around 2031. This retirement marks a significant transition, shifting responsibility for LEO infrastructure from government agencies toward commercially owned and operated space destinations.
The NASA Strategy for Commercial LEO Destinations
The impending end of the ISS mission is driving a fundamental shift in how the United States maintains a presence in low Earth orbit (LEO). NASA is transitioning from operating a massive space station to becoming a customer who purchases services from private industry. This approach is formalized under the Commercial LEO Development (CLD) program, which aims to stimulate the creation of new commercial platforms. The primary motivation is to realize substantial long-term cost savings, freeing up NASA’s resources to focus on deep space exploration, specifically the Artemis program.
Under the CLD program, NASA provides initial funding and technical assistance to several companies to mature their designs. The agency’s goal is to ensure a continuous, safe, and crew-capable platform is available before the ISS is decommissioned, preventing a gap in U.S. access to LEO. NASA will certify these commercial destinations and then buy the research time and astronaut access it requires, similar to the commercial cargo and crew transport model. This competitive model is intended to drive down operating costs and foster a robust new space economy.
Key Commercial Space Station Replacements
The replacement for the ISS will not be a single government-led project but a selection of competing, privately-developed destinations. Three major US-backed concepts are advancing under the CLD program, each with a distinct design and business focus. These commercial platforms aim for initial operations between 2028 and 2030, allowing for a two-year overlap with the ISS to ensure a smooth transition.
Axiom Station
Axiom Station, developed by Axiom Space, begins its assembly by docking modules directly to the International Space Station. The company plans to launch its first module to the ISS before 2028. Once sufficient modules have been assembled, this “Axiom Segment” will detach from the ISS and become an independent, free-flying commercial destination. This modular method leverages existing ISS infrastructure, fast-tracking its path to independent operation as early as 2028. The station focuses on commercial research, in-space manufacturing, and private astronaut missions, supporting a crew of four to eight people.
Orbital Reef
The Orbital Reef project is a collaboration between Blue Origin and Sierra Space, envisioned as a “mixed-use business park” in space. It is designed to serve a wide array of customers, including scientific researchers, industrial users, and space tourists. Sierra Space is contributing its Large Integrated Flexible Environment (LIFE) habitat, an inflatable module that offers significant internal volume. Current projections suggest a launch closer to the ISS retirement date, possibly by 2030. The station is planned to accommodate up to 10 people, leveraging the heavy-lift capacity of Blue Origin’s New Glenn rocket for its core modules.
Starlab
Starlab is a joint venture between Voyager Space and Airbus, distinguishing itself by being designed for a single-launch deployment. It is slated to be launched by SpaceX’s Starship vehicle, which is capable of orbiting the station’s large volume in one piece. Starlab is focused on providing a dedicated platform for science and technology development, capable of supporting a high volume of microgravity experiments. Expected to launch around 2028 or 2029, the station will feature a large inflatable habitat module and an advanced laboratory system, initially hosting up to four astronauts.
International Involvement and Non-US Stations
The transition to commercial LEO destinations impacts the ISS’s international partners, including ESA, JAXA, and CSA. These agencies have committed to supporting the ISS until 2030 but are not developing independent LEO replacements. Instead, they are expected to become future customers of the U.S. commercial stations, purchasing access for their astronauts and research programs. Their focus, like NASA’s, is shifting towards deep space exploration, with all three agencies collaborating on the Lunar Gateway, an outpost orbiting the Moon under the Artemis program.
Separately, the Tiangong Space Station (TSS), operated by the China Manned Space Agency, represents the only fully operational, non-commercial alternative to the ISS. Completed between 2021 and 2022, Tiangong is significantly smaller than the ISS, possessing about one-third of its pressurized volume, but it maintains a continuous human presence in LEO. It serves as an independent platform for scientific research and a geopolitical option for nations that may not utilize the US-led commercial destinations.
Decommissioning the International Space Station
The final stage of the ISS program requires a precise process to safely retire the 400-ton structure. The station cannot be allowed to fall to Earth uncontrolled, as debris from its large, dense components could pose a risk to populated areas. The plan is a controlled, targeted deorbit maneuver that will guide the station to re-enter the atmosphere over a remote area of the South Pacific Ocean, known as the spacecraft cemetery or Point Nemo.
To execute this maneuver, a purpose-built spacecraft called the U.S. Deorbit Vehicle (USDV) is being developed by SpaceX. This space tug will dock with the ISS after the crew has departed and provide the thrust needed for the descent. The station’s altitude will first be lowered gradually using natural atmospheric drag, and then the USDV will perform the braking burn in 2031. This action ensures the ISS breaks up and any surviving fragments fall harmlessly into the designated unpopulated zone.