CAPE CANAVERAL, Fla. (AP) — SpaceX will use a powerful, overflowing capsule to push the International Space Station out of orbit when it’s time for the sprawling lab.
NASA and Elon Musk’s company on Wednesday outlined a plan to burn up the space station on re-entry and submerge what’s left in the ocean, ideally in early 2031, when it reaches the 32-year mark. The space agency rejected other options, such as dismantling the station and bringing everything home or handing the keys over to someone else.
NASA gave SpaceX a $843 million contract destroy the station – the largest structure ever built off-planet.
Here is an overview of the work and future challenges:
Why get rid of the space station?
The space station is already showing signs of age. Russia and the US launched the first pieces in late 1998, and astronauts moved in two years later. Europe and Japan added their own segments, and Canada provided robotic arms. By the time NASA’s space shuttles departed in 2011, the station had grown to the size of a football field and weighed nearly 1 million pounds (430,000 kilograms). NASA estimates the station will operate until at least 2030. The goal is for private companies to launch their own space stations by then, with NASA serving as one of many customers. This strategy — already in place for station cargo and crew supplies — will free up NASA to focus on travel to the Moon and Mars. NASA could also decide to extend the life of the station if there are no commercial bases there yet. The aim is to have an overlap so that scientific research is not interrupted.
Why not bring it back to Earth?
NASA considered dismantling the space station and taking the pieces back to Earth, or letting private companies salvage the parts for their own planned bases. But according to NASA, the station was never supposed to be disassembled in orbit, and any such effort would be expensive as well as risky for the astronauts who would handle the disassembly. Besides, there is no spaceship as big as the old NASA space shuttles that can bring everything down. Another option would be to raise the empty station to a higher, more stable orbit. But even this was rejected due to logistical problems and the increased risk of space junk.
How will it be pulled down?
A visiting spacecraft periodically boosts the space station to keep it in orbit at about 260 miles (420 kilometers) high. Otherwise, it would keep falling and falling until it tumbled out of orbit uncontrollably. NASA wants to ensure a safe return through a remote part of the South Pacific or perhaps the Indian Ocean, so that means launching a spacecraft that will dock with the station and direct it to a watery grave. NASA expects some of the denser chunks, ranging in size from a microwave oven to a sedan, to survive in the narrow 2,000-kilometer-long debris field. NASA and its partners considered using three Russian supply ships for the job, but a more robust vessel was needed. The call went out to industry, and in June SpaceX won the contract to deorbit the vehicle.
What will a deorbital spacecraft look like?
SpaceX plans to use a regular Dragon capsule — the kind that carries supplies and astronauts to the space station — but with a much larger case containing 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 create a spacecraft powerful enough to guide the space station while resisting the thrusts and forces caused by increased atmospheric drag during final descent. This spacecraft will require an especially powerful rocket to get into orbit, according to NASA. The capsule will be launched 1 1/2 years before the planned demise of the station. The astronauts will still be on board as it gradually descends. Six months before the station was destroyed, the crew abandoned ship and returned home. Once the station is down about 137 miles (220 kilometers), Dragon would knock it down four days later.
Has this been done before?
NASA’s first space station, Skylab, crashed in 1979 and debris rained down on Australia and the surrounding Pacific. The space agency hoped that one of the first shuttle crews could attach a rocket to guide Skylab’s descent or raise its orbit. However, the Space Shuttle was not ready at the time, and did not make its first flight until 1981. Ground controllers managed to send Skylab into a slow fall and headed for the Indian Ocean. But some pieces also landed in Western Australia. Russia has more experience with incoming space stations. Mir operated for 15 years before being induced to make a fiery return over the Pacific in 2001. Before that, several Saljut stations bit the dust.
Will anything be saved?
NASA wants to bring back some small items from the space station for museum display, such as the ship’s bell and logs, patch panels and other memorabilia. These may come down on SpaceX supply ships in the last year or two. “Unfortunately, we can’t bring really, really big things home,” said NASA’s Ken Bowersox. “An emotional part of me would like to try to save some,” but the most practical approach is to knock everything down with one destructive blow, he said.
___
The Health and Science Department of the Associated Press receives support from the Science and Education Media Group of the Howard Hughes Medical Institute. All content is the sole responsibility of AP.