How will Nasa and SpaceX dispose of the retired space station?

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SpaceX has been tasked with the responsibility of deorbiting the International Space Station once it reaches the end of its operational life. The company, in collaboration with Nasa, announced on Wednesday their strategy to safely dispose of the colossal orbiting laboratory by guiding it into a controlled reentry and ultimately plunging the remnants into the ocean.The target date for this mission is set for early 2031, coinciding with the station’s 32nd anniversary in space.
After considering various alternatives, such as disassembling the station and returning its components to Earth or transferring ownership to another entity, Nasa determined that the most viable option was to decommission the ISS through a controlled deorbit. To accomplish this complex task, the space agency awarded SpaceX a substantial $843 million contract, recognising the company’s expertise and capabilities in space operations.
The International Space Station, a collaborative effort by Russia, the United States, Europe, Japan, and Canada, is exhibiting indications of ageing since its initial components were launched in 1998. Astronauts began inhabiting the station two years later, and over time, it expanded to its current size, comparable to a football field, with a mass of nearly 1 million pounds (430,000 kilograms).
Nasa anticipates that the station will remain operational until at least 2030, with the intention of private companies launching their own space stations by that time. Under this plan, Nasa would serve as one of many customers, a strategy already in place for station cargo and crew deliveries. This approach will allow Nasa to concentrate on lunar and Martian exploration.
If no commercial outposts are operational by 2030, Nasa may consider extending the station’s lifespan to ensure continuity in scientific research. The goal is to have an overlap between the current station and future commercial facilities to prevent any interruption in ongoing research activities.
After careful deliberation, Nasa has decided against the option of disassembling the space station and transporting its components back to Earth. The agency has also ruled out the possibility of allowing private companies to salvage the parts for their own planned outposts. According to Nasa, the station was never intended to be taken apart in orbit and any attempt to do so would not only be costly but also pose significant risks to the astronauts involved in the disassembly process. Moreover, there is currently no spacecraft as large as Nasa’s retired shuttles capable of bringing all the components back to Earth.
Nasa also considered the alternative of boosting the unoccupied station to a higher, more stable orbit. However, this option was also dismissed due to the logistical challenges involved and the increased risk of contributing to the growing problem of space debris. The agency has determined that the most prudent course of action is to allow the space station to remain in its current orbit until a more suitable solution can be found.
The International Space Station’s orbit is maintained at around 260 miles (420 kilometers) above Earth through periodic boosts from visiting spacecraft. Without these boosts, the station would gradually lose altitude until it eventually fell from orbit in an uncontrolled manner. To ensure a controlled and safe reentry, Nasa plans to guide the station to a remote area over the South Pacific or Indian Ocean.
Nasa anticipates that some denser components, ranging from the size of “a microwave oven to a sedan,” will survive the reentry and create a narrow debris field spanning 1,200 miles (2,000 kilometres). Initially, Nasa and its partners explored the possibility of using three Russian supply ships for the deorbiting process. However, it became evident that a more robust spacecraft was necessary. Consequently, Nasa sought proposals from the industry and, in June, awarded SpaceX the contract to develop a dedicated deorbit vehicle.
SpaceX intends to utilise a standard Dragon capsule, similar to those used for delivering supplies and transporting astronauts to the space station, but with a significantly larger trunk. This modified trunk will house an unprecedented 46 engines and carry more than 35,000 pounds (16,000 kilograms) of fuel.
Sarah Walker from SpaceX highlighted the difficulty in developing a spacecraft capable of controlling the space station while withstanding the increased atmospheric drag during the final descent phase.
Due to the spacecraft’s unique requirements, Nasa said that a particularly powerful rocket would be necessary to achieve orbit. The capsule is scheduled to launch 1 1/2 years before the planned decommissioning of the station. Astronauts will remain on board as the station is gradually brought down to a lower altitude. Six months prior to the station’s destruction, the crew will evacuate and return to Earth.
Once the station reaches an altitude of approximately 137 miles (220 kilometres), the Dragon capsule will initiate the final descent, bringing the station down within four days.
In 1979, Skylab, the inaugural space station of Nasa, plummeted back to Earth, scattering debris across Australia and the nearby Pacific Ocean. The agency had aspirations of utilising one of the initial space shuttle missions to connect a rocket to Skylab, allowing them to manipulate its descent or elevate its orbit. However, the shuttle was not prepared in time, with its maiden voyage occurring only in 1981. Mission control was able to initiate a gradual tumble in Skylab’s trajectory, targeting the Indian Ocean. Nevertheless, some fragments also reached Western Australia.
Russia possesses greater expertise in managing the reentry of space stations. Mir, which operated for 15 years, was deliberately directed to a fiery reentry over the Pacific in 2001. Before Mir, several Salyut stations similarly met their demise.
Nasa has expressed its desire to retrieve a selection of small objects from within the space station, with the intention of showcasing them in museums. These items include the ship’s bell, logs, panels adorned with patches, and other commemorative pieces. The plan is to transport these artefacts back to Earth using SpaceX supply vessels during the final one to two years of the station’s operation.
Ken Bowersox, a representative from Nasa, acknowledged the limitations of this approach, saying, “Unfortunately, we can’t bring home really, really big stuff.” While he admitted that his emotional side would be inclined to attempt to preserve some larger components, he conceded that the most pragmatic solution is to bring the entire structure down in a single, destructive event.



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