CAPE CANAVERAL, Fla. (AP) — SpaceX will use a powerful, improved capsule to launch the International Space Station out of orbit once the spacious laboratory expires.
NASA and Elon Musk’s company outlined a plan Wednesday to incinerate the space station upon re-entry and dump what’s left in the ocean, ideally in early 2031 when it reaches the 32-year mark. The space agency has ruled out other options, such as dismantling the station and bringing everything home or handing the keys to someone else.
NASA has awarded SpaceX an $843 million contract to demolish the station, the largest structure ever built off the planet.
Here is a summary of the work and challenges ahead:
Why are we getting rid of the space station?
The space station is already showing signs of aging. Russia and the United States launched the first pieces in late 1998, and astronauts moved in two years later. Europe and Japan added their own pieces, and Canada provided robotic arms. By the time NASA’s shuttles were retired in 2011, the station had grown to the size of a football field, with a mass of about 1 million pounds (430,000 kilograms). NASA estimates that the station will continue to exist 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, which is already in place for the station’s cargo and crew deliveries, would allow NASA to focus on trips to the Moon and Mars. NASA could also decide to extend the station’s life if there are no commercial outposts there yet. The goal is to provide overlap so that scientific research is not disrupted.
Why don’t we bring it back to Earth?
NASA considered dismantling the space station and returning the pieces to Earth, or allowing private companies to salvage the pieces for their own planned bases. However, NASA said dismantling the station in orbit was never intended, and such an effort would be expensive and risky for the astronauts who would perform the dismantling. Also, NASA does not have a spacecraft as large as the old shuttles to bring everything down. Another option was to take the empty station to a higher, more stable orbit. However, this was also rejected due to logistical issues and the increased risk of space debris.
How to lower it?
Visiting spacecraft would periodically accelerate the space station so that it would maintain an orbit about 260 miles (420 kilometers) high. Otherwise, it would continue to descend until it fell out of orbit uncontrollably. NASA wants to ensure a safe reentry over a remote part of the South Pacific or possibly the Indian Ocean, which would mean launching a spacecraft that would dock with the station and guide it toward a watery grave. NASA expects some of the denser pieces, ranging in size from a microwave oven to a sedan, to survive in a narrow debris field about 1,200 miles (2,000 kilometers) long. NASA and its partners considered using three Russian resupply ships for the job, but a more robust craft was needed. The call went out to industry, and in June, SpaceX won the contract for a deorbit vehicle.
What will the spacecraft look like after leaving orbit?
SpaceX plans to use a regular Dragon capsule, the kind that carries supplies and astronauts to the space station, but it has a much larger trunk that holds a record-breaking 46 engines and more than 35,000 pounds (16,000 kilograms) of fuel. The challenge, SpaceX’s Sarah Walker said, will be to create a spacecraft powerful enough to steer the space station while resisting the tugs and forces from increased atmospheric drag during the final descent. That spacecraft will need a particularly powerful rocket to reach orbit, according to NASA. The capsule will launch 1 1/2 years before the station’s scheduled descent. The astronauts will still be on board as the capsule gradually descends. Six months before the station’s descent, the crew will abandon ship and return home. When the station has reached about 137 miles (220 kilometers), Dragon will land it four days later.
Has this been done before?
NASA’s first space station, Skylab, crashed in 1979, sending debris raining down on Australia and the surrounding Pacific. The space agency hoped that one of the early shuttle crews could attach a rocket to control Skylab’s descent or boost its orbit. But the shuttle wasn’t ready by then, and its first flight didn’t take place until 1981. Ground controllers managed to send Skylab into a slow descent, aiming for the Indian Ocean. But some debris also landed in Western Australia. Russia has more experience with space stations that have landed. Mir operated for 15 years before being diverted to a fiery re-entry over the Pacific in 2001. Before that, several Salyut stations were dusted.
Can anything be salvaged?
NASA wants to bring back some smaller items from inside the space station, such as the ship’s bell and logs, patches and other memorabilia for museum display. These could be lowered by SpaceX supply ships in the last year or two. “Unfortunately, we can’t bring home the really, really big stuff,” NASA’s Ken Bowersox said. “The sentimental side of me would love to save some of it,” but the most practical approach is to bring everything down in one devastating blow, he said.
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