As of 2022, the space station has been in orbit for an impressive 21 years. As NASA and its partners originally planned to decommission after 15 years, the space station is long past its original due date. Even with mounting safety concerns, NASA has decided to extend the lifespan of the space station until 2031.
But while the space station has served humanity well, it can’t continue forever.
Why NASA wants to decommission the ISS
Why would NASA decommission the ISS? After all, the space station is an engineering feat — and an expensive one at that. The International Space Station is often cited as the most expensive structure ever built at a whopping $150 billion dollars.
Additionally, the station has been home to over 3,000 experiments due to its unique microgravity environment. With this in mind, it seems ludicrous to throw out such an important scientific tool.
However, according to NASA, age is doing a number on the space station. In recent years, there’s been an abundance of safety concerns on the ISS. Ranging from mysterious holes to leaky modules, the Russian segment of the station has been particularly worrisome — although the whole operation is likely to suffer as the years drag on.
As NASA explained in its January 2022 Transition Report:
“The technical lifetime of the ISS is limited by the primary structure, which includes the modules, radiators, and truss structures. Other systems such as power, environmental control and life support, and communications, are all repairable or replaceable on orbit. The lifetime of the primary structure is affected by dynamic loading (such as vehicle dockings/undockings) and orbital thermal cycling.”
In the name of astronaut safety, NASA has decided to put a limit on the lifespan of the ISS. Until recently, NASA’s tentative extended plan was to cease operations in 2028, but now the Space Station is proposed to go on for another two years.
Despite recent safety issues, NASA says that they have “high confidence that ISS life can be further extended through 2030.”
A fiery end
NASA’s “de-orbit plan” outlines the timeline of events that will happen in order to safely decommission the Space Station. According to NASA, they will slowly lower the elevation of the Space Station over the course of a few years leading up to 2031. This will be accomplished through what NASA calls “retrograde” maneuvers.
The International Space Station’s elevation actually lowers naturally because of atmospheric drag, so mission control usually instructs the station to perform “posigrade” maneuvers, which lift its elevation.
Eventually, the Space Station’s final crew will arrive sometime mid-2030. They will be tasked with tying up any loose ends on the station and set the final retrograde maneuvers into motion. As 2030 draws to an end, the Crew will head back to Earth, and ultimately leave the Space Station alone, once and for all.
While NASA considered bringing it down piecemeal, the agency says:
The International Space Station modules and truss structure were not designed to be easily disassembled in space. The space station covers an area about the size of a football field with initial assembly of the complex requiring 27 flights by NASA since retired space shuttle with its large cargo bay and multiple international partner missions over a span of 13 years. In addition, new hardware has recently been added to the space station, like the roll-out solar arrays and the Russian Nauka and Prichal modules. Any disassembly effort to safely return individual components would face significant logistical and financial challenges, requiring substantial work by astronauts and ground support personnel as well as a spacecraft with a capability similar to the space shuttle’s large cargo bay.
However, some later modules may be detached for future use by commercial partners, though many of those have yet to launch. The agency says:
There currently are no proposals from commercial providers to repurpose major structural parts of the International Space Station, and such plans would have to consider the cost and difficulty of reusing such pieces of station. NASA has entered into a contract for commercial modules to be attached to a space station docking port with plans to later detach, and awarded space act agreements for design of three free-flying commercial space stations.
Over the course of January 2031, NASA will begin — and end — the final phase. NASA will check that the Space Station is aligned with the South Pacific Oceanic Uninhabited Area (SPOUA). This is the area around Point Nemo, which is the furthest point on Earth from any landmass. Because of its isolated nature, Point Nemo has become a polestar for de-orbited spacecraft. Known as the “spacecraft cemetery,” there are hundreds of decimated satellites floating somewhere around Point Nemo.
As the Space Station gets closer to Earth in altitude, it actually gains orbital velocity. This is because the Earth’s gravitational pull is stronger as the Station draws nearer.
Soon, it will begin to pass through the atmosphere, and start to burn up. NASA will attempt to steer the station in a controlled manner towards the crash-landing area. Eventually, the fiery Space Station will careen into the cool Pacific waters and sink to its watery grave.
The agency says it expects three separate break-up events on the way toward Point Nemo:
- The solar array and radiators will separate from the station initially, which is why happened to both Mir and Skylab
- Shortly after the modules and truss segment will break off
- As the modules burn up and fragment, the truss will lose structural integrity
As all this happens, the outside of the modules — the external “skin” — will melt, exposing the hardware inside to the intense friction heat. They will melt shortly after. This means many of the modules will be destroyed before they reach Point Nemo — likely all but completely evaporating. Large parts of the truss, which are more heat resistant, will probably survive re-entry. It’s those components that will drown in Point Nemo.
While there have been a few Space Stations over the years, (Mir and Skylab) none have lasted as long — or had nearly as much significance as the ISS. It represents a unique opportunity for countries like the United States and Russia to work together in the pursuit of science. It’s called the International Space Station for a reason, after all.
Although there are plans for future Space Stations on the horizon, the ISS will be remembered no matter where it is — either in space, or in the deep depths of the Earth’s oceans.