SpaceX plans to use a powerful, enhanced capsule to deorbit the International Space Station (ISS) once its operational life concludes. On Wednesday, NASA and Elon Musk’s company outlined their strategy to incinerate the station on reentry, with the remnants ideally falling into the ocean around early 2031, marking 32 years of service. Other options, such as dismantling the station and returning parts to Earth or transferring ownership, were dismissed by NASA.
NASA has awarded SpaceX an $843 million contract to manage the station’s deorbiting, the most extensive structure ever assembled in space.
Launched in late 1998 by Russia and the US, the ISS has been showing signs of aging. Astronauts began inhabiting it two years later, with additional modules from Europe, Japan, and robotic arms from Canada. By 2011, the ISS had expanded to the size of a football field with a mass nearing 1 million pounds (430,000 kilograms). NASA expects the ISS to remain functional until at least 2030.
The plan is for private companies to launch their own space stations by then, with NASA becoming one of many clients. This approach, already applied to cargo and crew deliveries, will allow NASA to focus on lunar and Martian exploration. If private outposts are not ready, NASA might extend the ISS’s operational life to avoid disrupting scientific research.
NASA considered dismantling the ISS and salvaging parts for future stations but concluded it would be too costly and hazardous for astronauts. The absence of spacecraft as large as the old NASA shuttles also made this unfeasible. Raising the ISS to a higher orbit was another option but was dismissed due to logistical issues and increased space debris risk.
Currently, visiting spacecraft periodically adjust the ISS’s orbit to maintain its approximately 260-mile (420-kilometer) altitude. Without these adjustments, the ISS would gradually descend uncontrollably. To ensure a controlled reentry over a remote part of the South Pacific or Indian Ocean, NASA plans to use a spacecraft to dock with the ISS and steer it towards a safe crash site.
Some denser parts, ranging from the size of a microwave to a sedan, are expected to survive reentry, creating a debris field about 1,200 miles (2,000 kilometers) long. NASA initially considered using three Russian supply ships but opted for a more robust vehicle. SpaceX won the contract to build this deorbiting craft in June.
SpaceX will modify a Dragon capsule, typically used for carrying supplies and crew, to include a larger trunk with 46 engines and over 35,000 pounds (16,000 kilograms) of fuel. Sarah Walker from SpaceX noted the challenge of designing a spacecraft powerful enough to guide the ISS while withstanding increased atmospheric drag.
A powerful rocket will be required to launch this capsule, which will be sent to orbit 1.5 years before the ISS’s scheduled deorbit. Astronauts will remain on board during the station’s gradual descent, leaving six months before the final destruction. Once the ISS reaches about 137 miles (220 kilometers) in altitude, the Dragon capsule will bring it down within four days.
NASA intends to retrieve small items from the ISS, like the ship’s bell and logs, for museum display. These will be brought back by SpaceX supply ships in the last couple of years. Although it’s impractical to save large sections of the ISS, NASA’s Ken Bowersox acknowledges the emotional desire to preserve more significant parts but emphasizes the practicality of a complete, controlled deorbit.