Safeguarding Science in the Sky
For over 25 years, the International Space Station has been a beacon of international cooperation and scientific discovery, orbiting 250 miles above Earth1 .
The Floating Laboratory Facing Its Final Decade
It has provided a unique platform for research impossible to conduct on Earth, making significant strides in our journey to the Moon, Mars, and beyond1 . However, this iconic symbol of human achievement has now entered what safety experts call the "riskiest period of its existence"7 . As the station ages and faces escalating technical and budgetary challenges, the race is on to protect its final years of operation and secure the future of research in low Earth orbit.
The International Space Station is a monumental engineering achievement, but it is not getting any younger. The Aerospace Safety Advisory Panel (ASAP), a key NASA safety committee, has expressed grave concerns about the station's mounting risks7 .
Persistent and elusive problems are at the heart of these concerns. A primary worry is air leaks in the Russian Zvezda module, first identified in 2019. Investigations have yet to pinpoint a definitive root cause, and managing this issue requires continuous monitoring and operational workarounds, such as limiting the repressurization of the affected vestibule7 . This problem underscores the challenges of maintaining an aging structure in the harsh space environment.
Compounding these technical issues is a significant budget shortfall7 . Ensuring safety in this final phase requires adequate funding for maintenance, spare parts for critical life support systems, and managing cargo resupply missions, which have recently faced delays7 . The panel has warned that stretching limited resources could jeopardize the safe operation of the station and the broader plan to transition to commercial stations.
Persistent air leaks in the Russian segment could lead to loss of cabin pressure with an elusive root cause7 .
Budget shortfalls and delays in cargo resupply reduce ability to maintain spare parts and life support systems7 .
Continued operations and maintenance of the aging station
Planned delivery of the U.S. Deorbit Vehicle (USDV)
Deorbit operations planned for the 420-metric-ton station
Despite the challenges, the ISS remains a vital scientific platform. Its microgravity environment allows researchers to study phenomena in ways that are impossible on Earth, leading to breakthroughs across numerous fields8 .
The ISS is the perfect testbed for technologies needed for long-duration missions to the Moon and Mars. This includes developing advanced life support systems that recycle 98% of water—a crucial level for missions beyond low Earth orbit1 . Astronauts have also grown over 50 species of plants using aeroponic and hydroponic systems, a key step toward producing fresh food during deep-space missions1 .
Space has proven to be a powerful laboratory for medical research. The microgravity environment causes cells to behave differently, with symptoms in astronauts resembling the effects of aging on Earth8 . Furthermore, the study of protein crystals in microgravity can lead to improved drug formulations8 .
Understanding how fire behaves in space is critical for crew safety on all space missions. However, conducting large-scale fire experiments aboard an occupied spacecraft is far too dangerous. This is where the Spacecraft Fire Experiments (Saffire) came in—a series of crucial studies that cleverly used uncrewed Cygnus resupply craft after they departed the ISS4 .
The Saffire experiments were conducted in a safe, controlled manner. After a Cygnus spacecraft completed its cargo delivery to the ISS and was filled with trash, it would undock and move to a safe distance. Researchers on the ground would then remotely ignite a large-scale fire inside a sealed module within the empty spacecraft4 . The final experiment, Saffire-VI, tested flammability at different oxygen levels and demonstrated fire detection, monitoring, and post-fire cleanup capabilities4 .
"Changed our understanding of material flammability in low gravity" and demonstrated that, just as on Earth, smoke from a fire represents the most immediate hazard to the crew4 .
— David Urban, principal investigator for Saffire
| Experiment | Primary Focus | Key Insight |
|---|---|---|
| Saffire-I to V | Material flammability, flame spread | Provided foundational data on how fire spreads in microgravity4 |
| Saffire-VI (Final) | Flammability at different oxygen levels; fire detection and cleanup | Tested operational protocols for fire response; capped off the series4 |
The space station is equipped with specialized modules and hardware that make its diverse research possible. Here are some of the key facilities that form the backbone of orbital science5 6 .
A pressurized module supporting research in fluid physics, biology, and materials science5 .
The Japanese Experiment Module, featuring both a pressurized lab and an external platform for exposing experiments to space5 .
The U.S. primary research module, hosting experiments in everything from fundamental biology to technology demonstrations5 .
A Russian module that supports a variety of scientific research activities5 .
Allows astronauts to manufacture tools and parts on-demand, a critical capability for long missions far from Earth1 .
A growth chamber designed to study how plants grow in microgravity, supporting crop production for future missions1 .
With the ISS scheduled to retire around 2030, NASA is not planning to build another government-owned station. Instead, the strategy is to transition to commercially owned and operated space stations, where NASA will be one of many customers. This plan, known as the Commercial LEO Development (CLD) program, is already underway.
"There is no time to waste" in awarding contracts and supporting the entire ecosystem needed for this transition to succeed.
The International Space Station is more than a technological marvel; it is a testament to what humanity can achieve through global collaboration. As it navigates its riskiest years, the pressure is on to ensure its safe operation and legacy, which will ignite the future of commercial space stations.