How will NASA and SpaceX decommission the space station after it is decommissioned?

NASA and Elon Musk’s company on Wednesday outlined a plan to burn up the space station on re-entry and sink what’s left of it in the ocean, ideally by early 2031 when it will be 32 years old. The space agency rejected other options, such as disassembling the station and taking everything home or handing the keys to someone else.

NASA awarded SpaceX an $843 million contract to haul the station — the largest structure ever built on Earth.

The details of the work and challenges ahead are as follows:

Why get rid of the space station?

The space station is already showing signs of age. Russia and the U.S. launched its first parts in late 1998 and astronauts moved aboard two years later. Europe and Japan added parts of their own and Canada provided robotic arms. By the time NASA’s shuttles retired in 2011, the station was the size of a football field, weighing about 1 million pounds (430,000 kilograms). NASA estimates the station will last until at least 2030. The goal is to have private companies launch their own space stations by then, with NASA as one of many customers. That strategy — similar to what’s already in place for station cargo and crew deliveries — would free NASA to focus on journeys to the moon and Mars. NASA could also decide to extend the station’s life if no commercial outposts are built yet. The aim is to have overlap so that scientific research isn’t interrupted.

Why not bring it back to Earth?

NASA considered dismantling the space station and bringing its pieces back to Earth or letting private companies salvage the parts for their planned outposts. But according to NASA, the station was never intended to be taken apart in orbit, and any such attempt would be expensive and also risky for the astronauts who would be tasked with taking it apart. Plus, there is no spacecraft as big as NASA’s old shuttle that could bring everything down. Another option would be to move the empty station to a higher, more stable orbit. But this, too, was ruled out due to logistical issues and the increased risk of space junk.

How will it be brought down?

Visiting spacecraft periodically boost the space station so it remains in an orbit about 260 miles (420 kilometers) high. Otherwise, it will continue to sink lower and lower until it falls uncontrollably out of orbit. NASA wants to ensure a safe reentry over a remote part of the South Pacific or possibly the Indian Ocean, so that means launching a spacecraft that will dock at the station and lead it to a watery grave. NASA hopes some dense pieces will remain in a narrow debris field about 1,200 miles (2,000 kilometers) long, ranging in size from a microwave oven to a sedan. NASA and its partners considered using three Russian supply ships for the job, but a more robust craft was needed.

What would a deorbit spacecraft look like?

SpaceX plans to use an ordinary Dragon capsule — the one that carries supplies and astronauts to the space station — but with a much larger trunk that holds a record 46 engines and more than 35,000 pounds (16,000 kilograms) of fuel. SpaceX’s Sarah Walker said the challenge will be to build a spacecraft that can guide itself to the space station while resisting the drag and forces from increased atmospheric resistance during the final descent. This spacecraft will need a particularly powerful rocket to get into orbit, according to NASA. The capsule will be launched about a year and a half before the station’s planned demise. Astronauts will still be aboard as it is slowly lowered. Six months before the station’s destruction, the crew will abandon ship and return home

Has this been done before?

NASA’s first space station, Skylab, crashed in 1979, with debris raining down on Australia and the surrounding Pacific. The space agency had hoped that one of the first space shuttle crews could attach a rocket to control Skylab’s landing or raise its orbit. But the shuttle wasn’t ready by then, with its first flight not taking place until 1981. Ground controllers managed to bring Skylab down softly, aiming for the Indian Ocean. But some pieces also fell into western Australia. Russia has more experience with visiting space stations. Mir operated for 15 years before being guided to a fiery re-entry over the Pacific Ocean in 2001. Before that, several Salyut stations crumbled to dust.

Will there be anything left?

NASA wants to bring back some of the smaller items from inside the space station to display them in a museum, such as the ship’s bell and logs, patched panels and other souvenirs. They could come down on SpaceX supply ships in the final year or two. “Unfortunately, we can’t really bring the very large items home,” said NASA’s Ken Bowersox. “The emotional part of me would love to try to save something,” he said, “but the most practical way is to rip everything down in one devastating blow.”

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Published: July 18, 2024, 12:48 PM IST