How NASA and SpaceX plan to deorbit the space station after retirement

NASA and SpaceX Plan to Deorbit International Space Station in 2031

SpaceX, in collaboration with NASA, will employ a powerful, enhanced capsule to deliberately bring the International Space Station (ISS) back to Earth, targeting a controlled descent and reentry around early 2031. This plan, revealed recently, aims to safely burn up the ISS over the ocean, marking the end of its operation as it approaches its 32-year mark in space.

Reasons for Decommissioning the ISS

The International Space Station, which has been in use since the first modules were launched in late 1998, is already showing signs of aging. Astronauts have inhabited the ISS since 2000, and its structure includes contributions from Europe, Japan, and Canada. By the time NASA retired its shuttle program in 2011, the ISS had grown significantly, with a mass close to 1 million pounds.

NASA anticipates that the ISS will remain operational until at least 2030. The ultimate goal is for private companies to develop their own space stations, with NASA serving as merely one of many customers. This transition is intended to free NASA to concentrate on missions to the moon and Mars. Should no commercial space stations be in place by 2030, NASA may opt to extend the ISS's life to ensure ongoing scientific research without interruption.

Alternative Options Considered

Various options were considered for the ISS's future. These included dismantling it and returning the pieces to Earth or letting private companies repurpose its components. However, dismantling was deemed too expensive and risky, as it would involve astronauts performing complex disassembly operations. Boosting the ISS to a higher, more stable orbit was also discarded due to logistical challenges and the increased risk of space debris.

The Deorbit Plan

To create a controlled reentry, a spacecraft will dock with the ISS to guide it into a remote part of the ocean, such as the South Pacific or Indian Ocean. While Russian spacecraft were considered for this task, SpaceX's proposal for a more robust solution won the contract in June. The dedicated deorbit vehicle will be a Dragon capsule equipped with 46 engines and over 35,000 pounds of fuel, significantly enhancing its capability to guide the ISS's descent safely.

Challenges Ahead

Key challenges include developing a spacecraft strong enough to navigate atmospheric drag and other forces during the ISS's descent. The Dragon capsule will be launched approximately 1.5 years before the ISS's planned deorbit. Astronauts will remain aboard to ensure the station’s controlled descent until about six months before the final phase, after which they will evacuate. The Dragon vehicle will then take over, bringing the ISS down to about 137 miles in altitude and managing its final descent four days later.

Precedents and Experiences

NASA's previous space station, Skylab, reentered Earth’s atmosphere in 1979, with debris impacting Australia. Similarly, Russia has experience with the controlled reentry of its Mir space station and several Salyut stations.

Salvaging Memorabilia

While large components cannot be brought back, NASA plans to retrieve smaller items for museum displays. These could include significant instruments, logs, and mementos, transported back on SpaceX supply ships in the final years of the ISS’s operation.

NASA's practical approach emphasizes a single, destructive reentry to manage the ISS decommissioning effectively, balancing the emotional desire to preserve parts of this historic structure with the realistic limitations of space logistics.