The ISS and Beyond? Towards the End of a Space Chapter

ISS: Cooperation in Low Orbit, Between Technical Feats and Future Challenges

A low orbit, a rapid cycle

The International Space Station (ISS) is positioned in a low Earth orbit at an average altitude of 415 km. At this altitude, the station completes a full orbit of the Earth every 90 minutes, or about 16 revolutions per day. Its orbital speed is 27,700 km/h, or 7.7 km/s, which means the astronauts on board observe about 16 sunrises and sunsets every day, a completely disrupted biological rhythm.

A continuously inhabited laboratory since 2000

The ISS has been continuously occupied since November 2000 by an international crew usually consisting of six astronauts. This personnel lives and works in a microgravity environment, dedicating most of their time to scientific experiments in fluid physics, cell biology, space medicine, Earth observation, and even quantum mechanics.

An unprecedented collaboration

Launched in 1998, the ISS program is a major multinational achievement. Led by NASA, it also involves Roscosmos (formerly FKA), the European Space Agency (ESA), the Japanese agency JAXA, and the Canadian agency CSA. The construction of the station, which is modular, spans more than a decade, with a main assembly phase completed in 2011. But the development of the station continued well beyond that, with the regular addition of new modules and instruments.

Retired shuttles, reduced logistics

Until 2011, American space shuttles allowed the transport of heavy loads and up to eight astronauts at a time, ensuring a sustained logistical pace between Earth and the ISS. In parallel, Russian Soyuz capsules ensured a regular rotation of three astronauts. The retirement of the shuttles created a logistical bottleneck. Since then, the question of replacing these orbital vehicles has become crucial.

A postponed but inevitable deadline

Initially scheduled for 2015, the end of life of the ISS has been postponed several times thanks to targeted renovations and an extension of the program. However, the aging of the structures, repeated micro-impacts, and corrosion due to the space environment require seriously considering its decommissioning between 2028 and 2030. This process will have to include a controlled deorbiting to sink the debris in the South Pacific, at Point Nemo, far from any human habitation.

The end of an orbital laboratory: What orbital stations for tomorrow?

The departure of the ISS marks a strategic turning point. Several public and private actors are preparing replacements for this colossal structure, which are more modular, autonomous, and targeted:

• Lunar Gateway (NASA/ESA/JAXA/CSA): a station in lunar orbit, dedicated to the logistics of the Artemis lunar missions.
• Tiangong (China): already operational, the Chinese modular station continues its experiments and opens up to international partnerships.
• Starlab (Voyager Space/NASA): commercial station project, with a commissioning scheduled for the late 2020s.
• Blue Origin Orbital Reef: concept of a private station for research, tourism, and industrial production in microgravity.

ISS: a planned and controlled end

The deorbiting of the ISS, planned between 2028 and 2030, will have to be finely orchestrated to avoid any uncontrolled re-entry. Its orbit will be gradually lowered so that it disintegrates in the Earth's atmosphere, with the remaining debris falling into the "Point Nemo", an uninhabited area of the Pacific Ocean.

Comparative table of future orbital stations

The post-ISS era will be marked by a diversification of actors and objectives. The unique and multinational station will give way to an archipelago of specialized stations. Human exploration of space is thus entering a more commercial, more modular, and potentially more sustainable era.

References:
• NASA, International Space Station Overview
• ESA, European Space Agency
• CNSA, China Manned Space Agency
• Blue Origin, Orbital Reef Project
• Axiom Space, Axiom Station Project

After the ISS: What Future for Low Orbit Stations?

As the ISS approaches the end of its operational cycle, a new generation of orbital stations is emerging on the horizon. The low Earth orbit (LEO) environment remains strategic for humanity: both an observation zone, a scientific research area, a technological demonstration site, and an industrial development space. But the models are changing: large institutional infrastructures are giving way to lighter, modular, specialized, and often commercial stations.

Towards a partial privatization of low orbit

With the gradual withdrawal of large state programs, new private actors are taking over. NASA, rather than replacing the ISS alone, is financing partnerships with companies such as Axiom Space, Voyager Space, or Blue Origin. These commercial stations will have the mission to offer various services: astronaut accommodation, pharmaceutical research, material manufacturing in microgravity, and even space tourism. This transition marks a break: space is also becoming an economic field.

Maintaining scientific and logistical objectives

The future stations will not be simple commercial substitutes. Their design integrates ultra-compact pressurized modules, autonomous life support systems, robotic arms, and interoperability with various orbital vehicles (Dragon, Starliner, Dream Chaser). The major agencies - NASA, ESA, JAXA - will continue to conduct fundamental experiments in controlled environments, while outsourcing the infrastructure to private partners. This public/private hybridization could make access to space more flexible, while maintaining scientific excellence.

Increasing modularity and functional specialization

One of the major evolutions lies in modularity. Unlike the ISS, the next stations are designed from the outset to be scalable: habitation, production, biology, or medicine modules can be added or removed as needed. Some stations will be completely autonomous, others will serve as logistical relay points or test platforms for long-duration life in orbit. We are thus witnessing the emergence of a true orbital ecosystem in LEO.

Technological and legal challenges

Despite their potential, these projects must overcome several obstacles. On the technical level, the durability of the structures, protection against space debris, water and air recycling, as well as robotic maintenance represent major challenges. On the legal level, the management of orbital traffic, responsibility in case of incidents, and the sharing of resources in LEO require strengthened international agreements, particularly within the framework of the 1967 Outer Space Treaty.

Towards an orbital archipelago

The era of the single station could thus give way to an orbital archipelago, composed of diverse and interconnected platforms. Some will be oriented towards fundamental research, others towards industrial production, space training, or tourism. This controlled fragmentation allows for greater resilience of the space system, while opening the way to expanded cooperation between states, companies, and scientific institutions.

References:
• NASA, Commercial LEO Destinations Overview (2023)
• Blue Origin, Orbital Reef Project Details (2024)
• Axiom Space, Habitation Module Roadmap (2024)
• CNSA, Tiangong Program (cmse.gov.cn)
• ESA, Lunar Gateway (esa.int)