NASA’s solution is to lower the ISS to a lower orbit, allowing for a controlled descent into Earth’s atmosphere before it’s completely demolished.
The International Space Station (ISS) is an international space complex consisting of 7 modules, measuring 109 meters in length, and operating in low Earth orbit. Construction of the ISS began in 1998 and continued until its completion in 2011. In addition to NASA, the major partners on the ISS include the Russian space agency (Roscosmos), the European Space Agency, the Japan Aerospace Exploration Agency, and the Canadian Space Agency.
When the ISS was initially planned, NASA and its partners intended to use the space station for a period of 15 years. However, its operational time extended beyond expectations as it continued to serve as a hub for scientific research.
After 24 years of operation, the physical structure of the station deteriorated over time. The continuous arrival of spacecraft and harsh operating conditions led to components of the station reaching a state beyond repair. As a result, in 2022, NASA outlined a plan to retire the ISS in 2030 and bring it back to Earth in January 2031.
The challenge at hand is how to safely deconstruct this 100-ton structure.
How do you handle a 400-ton artificial structure in low Earth orbit?
Unlike small rockets or spacecraft, the ISS cannot be destroyed or moved to a “space graveyard” for long-term storage. However, if not handled correctly, the station will re-enter Earth or pose a risk to future missions.
The ISS is currently orbiting Earth at a distance of over 400 km from the surface. Due to the immense size of its solar panels, the ISS can actually be spotted with the naked eye during dawn or dusk when flying over a region.
In essence, pushing the ISS into a higher orbit is infeasible, as it would require an immense amount of energy, not to mention that the stresses on the propulsion vehicle might lead to its catastrophic failure.
NASA’s alternative solution is to lower the ISS into a lower orbit, allowing for a controlled descent into Earth’s atmosphere. During reentry, the ISS will burn up, and any remaining debris will fall into an uninhabited area of the ocean.
To accomplish this, NASA initially proposed using a series of Russian Progress cargo spacecraft to push the ISS to the desired orbit. However, a year-long NASA and ISS partner study found that this approach wouldn’t work as expected. Furthermore, Russia’s plan to depart the ISS in 2028 and deteriorating relations with other partners made this option less viable.
Instead, NASA has put forward a proposal with American companies to develop a vehicle called the United States Deorbit Vehicle (USDV). The USDV would be responsible for actively guiding the ISS out of orbit and into Earth’s atmosphere in the final phase, after the station naturally lowers in orbit.
According to NASA’s plan, the USDV would rendezvous and dock with the ISS. It would then perform technical maneuvers to control the station’s status and velocity, guiding it out of orbit and towards Earth. At this point, the entire ISS would reach a maximum velocity of 43,450 km/h to pass through Earth’s atmosphere, burning up at temperatures of up to 5,300 degrees F (2,900 degrees C) during reentry before plunging into our planet’s surface.
It is estimated that NASA spends approximately 3 billion USD annually to operate the ISS. In total, there have been 258 astronauts and passengers from 20 different countries who have visited the ISS as of May 2022. Most of them came from the United States (158 individuals) and Russia (54 individuals).
However, many experts consider this approach highly risky due to uncontrollable variables. If things don’t go according to plan, the ISS could become a massive uncontrolled projectile causing significant damage.
It’s worth noting that some have suggested the ISS should be dismantled into smaller pieces or modules before they are individually brought back to Earth via rockets. However, this plan is also challenging to execute. If the ISS ceases operation, the process of connecting with the station for component removal becomes unfeasible or extremely difficult.
NASA itself acknowledges that it will take several years to develop, test, and certify the program before a specific plan is put into place. It’s also not ruled out that the idea could be scrapped and replaced with a more feasible alternative.