The Uncertain Future of the International Space Station

Obsolescence, leaks, and space debris increasingly endanger crew safety. According to NASA’s Office of the Inspector General, the emergency capsule launch system lacks sufficient redundancy, and there are budgetary issues.

BY EMILIO COZZI

Those who wish to write a space thriller screenplay set on the International Space Station would
find rich inspiration, including geopolitical elements, in the latest report from NASA’s inspector general. This would not be a science fiction movie: the oversight authority conducts periodic analyses of the American space agency’s activities, with a focus on uncovering flaws. It’s hardly a spoiler to reveal that the 46-page document, titled “NASA’s Management of Risks to Sustaining ISS Operations through 2030,” is filled with concerns about the orbiting laboratory.
In summary, while the ISS system is considered safe, nearly every aspect covered in the report reveals issues that could lead to the end of operations, an inability to continue managing activities in orbit as they are now, or a discontinuation of low-orbit activities without a long-planned transition to commercial space stations. The risk to astronauts is also clearly outlined. The station has aging issues, the risk posed by orbital debris is growing, and while all these factors increase the (albeit remote) likelihood of an emergency evacuation, the transport system is still not efficient enough to provide replacement parts and “lifeboats” should an evacuation order be issued. Additionally, Russia has not committed to extending operations beyond 2028, which presents another significant unknown for overall management.

An Aging Facility

Starting with this phrase: “NASA faces increasing risks in sustaining ISS operations through 2030.” Assembled beginning in 1998 and continuously inhabited since 2000, today the ISS has a few leaks. They are small and not immediately concerning, but increasingly important. Located in the tunnel leading to the Russian Zvezda service module (the first to be launched), these leaks have been mitigated but never fully resolved. Their cause remains unknown, possibly due to structural welds.
“NASA and Roscosmos continuously monitor the leak rates and close the service module hatch when access is not required,” reads the report. “Sealing the module minimizes air loss and isolates the leak. Although the ISS could continue to operate with the hatch permanently closed, this could impact cargo delivery, as there would be one less entry point.”

Ordering Spare Parts

In the coming years, system obsolescence may require extraordinary maintenance and spare parts. Just this year, astronauts had to store urine in special containers temporarily, awaiting a new pump for the treatment system that cleans it and recycles it into water. The replacement part was supposed to arrive on the Starliner capsule, which faced several delays.
All ISS partners monitor and certify their segments, environments, and systems for which they are responsible. The station consists mainly of two “quarters,” the Russian and the Western or American segments. The structural integrity of the U.S. segment is monitored and certified under a service contract with Boeing. “Currently, the ISS is structurally certified through 2028. NASA’s contract with Boeing for station support, including spare parts procurement and maintenance, expires at the end of fiscal year 2024. As of July 2024, NASA and Boeing are negotiating an extension.” Future demands for replacement parts are expected to increase for what is now an efficient “vintage machine,” an industry that must be maintained at high costs, with typically long lead times and lacking a flexible cargo supply system for transporting goods. For now, only SpaceX provides American shuttle services to the ISS, delivering both its Dragon capsules and Northrop Grumman’s Cygnus until at least August 2025, when the Antares rocket engines are exhausted.

Certifying the “End of Life”

Certification is done every four years, but NASA plans to initiate an “end-of-life” certification, i.e., for when the ISS structure will no longer be usable for safe operations. The document is clear on this point: “NASA and Boeing will conduct tests and analyses on critical ISS structures to predict the earliest point at which one of these would fail, indicating when the station can no longer operate safely. This is a change from previous structural certifications, typically performed at four year intervals.”
The well-known deadline aligns with 2030, when the ISS is expected to be decommissioned, deorbited, and dragged down by a “tow truck” designed by SpaceX. But as the following paragraphs will discuss, resources, timelines, and methods remain uncertain. So much so that the Inspector General suggests alternative solutions that consider further extending the operational life. Another scenario is that everything could end much sooner: in this case, an emergency deorbiting would be necessary in the event of a major incident (such as an impact with a large piece of debris) requiring the ISS’s immediate descent. A plan already agreed upon with Roscosmos, the Russian space agency.
The report highlights that “in the last 25 years, the ISS program has not encountered an event requiring an emergency deorbiting of the station. However, NASA’s Aerospace Safety Advisory Panel officials observed an increasing risk of an unplanned ISS deorbit due to the rising number of space objects in its path. In our opinion, the new emergency deorbit plan, with roles and responsibilities assigned to partners, helps manage safety risks for the crew and people and property on Earth.”
What would happen if Moscow decided not to contribute to ISS operations beyond 2028? The engines that adjust its altitude, maintaining it in orbit and maneuvering it to avoid impacts, are those of the Russian modules. This is especially critical given the other (yet another) significant issue.

Orbital Debris: A “New” Problem

Since the space station has been in orbit, satellites and objects in low Earth orbit have increased from just over 1,500 to more than 12,000. The issue of space debris has become worrisome, and recent reports highlight this concern. Incidents involving exploded, decommissioned satellites and ASAT (anti-satellite) tests—like Russia’s in November 2021—have generated clouds of fragments often sharing the ISS’s orbital plane. It’s noted that, despite accepting some level of risk, no new shielding will be added.
Instead, investments will focus on improving ground tracking of space debris: “NASA estimates that about 100 million small debris particles are currently not tracked or avoided by spacecraft, though they are large enough to cause damage or even destruction.” Additionally, the smaller fragments, while unable to cause catastrophic damage, can still puncture astronauts’ suits. This is known as the “Kessler Syndrome,” a vicious cycle in which an increasing number of objects heightens the risk of collisions and explosions in orbit, leading to a further, uncontrolled increase in debris. This effect resembles a chain reaction, similar to a landslide.

“Lifeboats”

A scenario is emerging involving an aging structure requiring extensive maintenance, whose integrity is increasingly threatened by external factors: space debris. The probability of an emergency evacuation being necessary is still low but now carries more risk. In almost 25 years, ISS occupants have never been required to leave for an emergency return to Earth. However, they have occasionally had to take refuge in capsules (the same ones used for arrival, now Soyuz and Dragon) due to the threat posed by nearby orbital debris. It’s worth asking what happens when the problem affects the very means of transport.
The answer became clear when Sunita Williams and Butch Wilmore, for several weeks, found themselves without a means of return. They were supposed to use Boeing’s Starliner, but due to issues, NASA opted to return it to Earth uncrewed. Until a Dragon capsule with two free seats arrived, Williams and Wilmore would have had no way to evacuate the station in an emergency. A similar situation occurred in 2023, when a Soyuz capsule with cooling system damage was replaced with an uncrewed one.
At this point in the ISS’s operational lifespan, redundancy in transportation systems was expected to be ensured by private companies. However, the Soyuz incident “revealed that when a crew vehicle is damaged, evacuation options are limited. According to ISS Program officials and NASA’s Office of Safety and Mission Assurance, NASA and its partners do not have readily available launch vehicles for impromptu evacuations due to prohibitive costs and the extra certification time required, even in the unlikely case of an emergency.” The lack of Boeing’s Starliner certification significantly impacts this situation, highlighting the issue in stark terms. In short, if two astronauts are “stranded” on the ISS, there’s currently no system for a quick rescue.
This issue is becoming increasingly relevant today, with the ISS occupancy rate higher than before and its decommissioning drawing nearer. However, it’s worth noting the alternative scenario under consideration: extending the ISS’s lifespan until at least one private space station is operational, allowing for the continued pursuit of scientific experiments, innovation, and astronaut training for future missions to the Moon, Mars, and beyond.

How and When to Deorbit the Station

The ISS won’t stay up there forever; it’s costly and, by now, fragile. It also isn’t viable as a monument, given that its low orbit requires constant maneuvers to keep it in position. The plan is to bring it down in a remote part of the Pacific, possibly in 2031. Initially, the idea was to use the engines of three Russian Progress capsules to push it down. However, it became clear that wouldn’t be sufficient. Consequently, SpaceX was commissioned to develop a vehicle specifically designed to dock with the ISS and tow it into a controlled descent over the ocean.
The contract is worth $843 million, but it doesn’t include launch costs, anticipated for 2029, or operational expenses in orbit. The new government estimate for the “decommissioning” totals around $1.5 billion. Two uncertainties remain: securing the necessary funds and understanding Russia’s intentions, given that half of the space station is theirs.
The report states, “NASA and the U.S. industry have approximately five and a half years to design, develop, test, produce, and launch the U.S. deorbiting vehicle by 2029 [to] achieve the ISS deorbiting goal set for 2031. We found this timeline unrealistic compared to other major NASA flight programs, which have typically taken about eight and a half years from contract award to first operational flight.” There’s little optimism, though some consideration is given to modifying the Dragon to reduce the time and costs associated with developing the deorbiting vehicle. Budgeting remains a serious headache.

Tightening the Purse Strings

In March 2024, Congress allocated $2.88 billion for the ISS program and for cargo and crew transport programs—about $50 million less than in fiscal year 2023 and roughly $283 million less than the President’s budget request for fiscal year 2024. The agency is conducting internal budget reviews to identify potential savings in the ISS program to account for reduced funding in fiscal year 2024 and to assess the impact on NASA’s fiscal year 2025 budget submission. Put simply, NASA must find ways to save.
As of 2022, the International Space Station had cost $118 billion in total. NASA spends $3 billion a year “on operations, maintenance, research, and transporting cargo and crew to the ISS.” But there’s a further cold splash of reality: “NASA will not be able to achieve significant cost savings on transportation in the near future without reducing the number of cargo and crew flights, meaning that the expected savings may not be realistic.”

Seeking a Positive Conclusion

The International Space Station is a complex system, kept functional through a delicate balance and top-tier engineering. The “grains of sand” that could disrupt it are increasingly evident. While astronaut safety is never compromised, as with any space activity, a reasonable level of risk must be accepted. The Inspector General’s report raises no alarms, but risks remain; cracks are present and need to be addressed. Planning the end and transition of humanity’s most ambitious project beyond the atmosphere is challenging, especially without knowing the intentions of the partner who helped build it and owns half of it. Space diplomacy has managed the remarkable feat of sustaining this colossal project despite earthly tensions and conflicts. The hope is for a positive outcome.