The International Space Station (ISS) has just celebrated a significant milestone, marking the 25th anniversary of continuous human occupation as of Sunday, November 2. This achievement secures the ISS's place in history as one of humanity's most remarkable and expensive technological feats. However, despite this momentous occasion, the future of the ISS is uncertain, as it is approaching the end of its operational life.
NASA and its international partners have set a timeline for the deorbit of the aging space station, planning to bring it down by the end of 2030. To execute this complex operation, they will utilize a modified, robust version of SpaceX's Dragon cargo capsule. This capsule is designed to safely transport the ISS to its final resting place: an uninhabited area of the ocean known as the spacecraft cemetery.
Point Nemo, named after the iconic submarine captain from Jules Verne's classic novel, is located in the Pacific Ocean at coordinates 48°52.6′S 123°23.6′W. This remote spot is approximately 2,688 kilometers (1,670 miles) from the nearest land, which includes Ducie Island, part of the Pitcairn Islands, Motu Nui from the Easter Islands, and Maher Island in Antarctica. The U.S. National Oceanic and Atmospheric Administration has highlighted Point Nemo's strategic importance for mission planners, who have safely disposed of several hundred large spacecraft in this area over the decades.
The remoteness of Point Nemo significantly minimizes the risk of falling debris harming people or infrastructure. As the ISS is deorbited, there is virtually no chance that any remaining hardware will hit a passing ship or inhabited area—making it a desirable location for reentry operations.
As the ISS prepares for its descent, NASA engineers anticipate that the breakup of the station will occur in a series of three stages. Initially, the solar arrays and radiators will separate, followed by the breakup of intact modules and the truss segment. Finally, individual module fragmentation and the loss of structural integrity of the truss will occur. This information comes from an official FAQ detailing the ISS transition plan.
During the reentry process, the intense heat generated will cause the external skin of the modules to melt, exposing internal components to rapid heating. While most of the ISS hardware is expected to burn up or vaporize upon reentry, some denser or heat-resistant parts, like the truss sections, may survive and splash down in the uninhabited ocean region.
The reentry strategies for previous space stations, such as the Soviet-Russian Mir and NASA's Skylab, provide valuable insights for current mission planners. In March 2001, Russia successfully guided Mir to a controlled reentry near Point Nemo. Conversely, NASA's attempt to deorbit Skylab in July 1979 was less successful; charred debris landed across a wide area of Western Australia, leading to a $400 fine for NASA for littering.
As the ISS approaches its end of life, the lessons learned from its operation and reentry will be crucial as Earth’s orbit becomes increasingly crowded. The future of space exploration will depend on careful planning and execution to ensure the safety of both the planet and its inhabitants.
