CAPE CANAVERAL, Fla. (AP) — SpaceX plans to use a powerfully modified capsule to deorbit the International Space Station once the vast laboratory’s lifespan is up.
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 into the ocean, ideally in early 2031, when the station will enter its 32nd year. NASA has rejected other options, such as dismantling the station and bringing everything back to Earth or handing the keys over to someone else.
NASA to SpaceX $843 million contract To destroy the space station, the largest structure ever constructed outside of Earth.
Future work and challenges are outlined below:
Why decommission the space station?
The space station is already showing signs of aging. Russia and the United States launched the first parts in late 1998, and astronauts were stationed there two years later. Europe and Japan added their own segments, and Canada provided a robotic arm. By the time NASA’s space shuttles retired in 2011, the station had grown to the size of a football field and a mass of nearly 1 million pounds (430,000 kilograms). NASA estimates that the station will last until at least 2030. The goal is that private companies will launch their own space stations by then, with NASA being one of many customers. This strategy, already in place for transporting cargo and crew to the station, would allow NASA to focus on trips to the Moon and Mars. If a commercial base is not yet there, NASA may also decide to extend the station’s lifespan. The aim is to have a period of overlap so that scientific research is not interrupted.
Why not bring that back to Earth?
NASA considered dismantling the space station and returning it to Earth, or having private companies salvage parts for their own planned bases. But NASA said the station wasn’t meant to be dismantled in orbit, and such an operation would be expensive and dangerous for the astronauts doing the dismantling. Plus, you can’t get everything off a spacecraft as big as NASA’s old shuttles. Another option would be to lift the empty station into a higher, more stable orbit, but that was also rejected due to logistical challenges and the increased risk of space debris.
How do we defeat it?
A visiting spacecraft would periodically boost the space station to keep it in orbit at an altitude of about 260 miles (420 kilometers); otherwise it would fall lower and lower, eventually losing control and falling out of orbit. NASA wants to ensure a safe re-entry into a remote area in the South Pacific or Indian Ocean, so it would have to launch a spacecraft to dock with the station and guide it to an underwater grave. NASA expects dense debris ranging in size from a microwave oven to a sedan to survive in the narrow debris field, 1,200 miles (2,000 kilometers) long. NASA and its partners considered using three Russian resupply ships for the task, but a more rugged spacecraft was needed. A call was made to industry, and SpaceX won the contract for a de-orbiter in June.
What would a deorbiting spacecraft look like?
SpaceX plans to use a regular Dragon capsule (the one that carries supplies and astronauts to the space station), but with a much larger trunk, capable of carrying 46 engines and more than 35,000 pounds (16,000 kilograms) of fuel, the most ever. SpaceX’s Sarah Walker said the challenge will be to build a spacecraft powerful enough to guide the space station while resisting the gravitational pull and forces of increasing atmospheric drag during the final descent. According to NASA, the spacecraft will need an extra powerful rocket just to get into orbit. The capsule will be launched a year and a half before the station’s scheduled destruction. The astronauts will remain on board as the capsule gradually descends. Six months before the station’s destruction, the crew will abandon the spacecraft and return home. Once the station has descended to an altitude of about 137 miles (220 kilometers), Dragon will drop it off four days later.
Has this been done before?
NASA’s first space station, Skylab, crashed in 1979, showering debris over Australia and the surrounding Pacific Ocean. NASA hoped that one of the crew of the first space shuttle could attach a rocket to control Skylab’s descent or accelerate it into orbit. However, the shuttle was not ready at the time, and its first flight did not take place until 1981. Ground controllers managed to slowly rotate Skylab toward the Indian Ocean, but some of the debris also fell in Western Australia. Russia has more experience with landing space stations; Mir operated for 15 years before re-entering the Pacific Ocean in flames in 2001. Several Salyut stations had disappeared before that.
Will anything be saved?
NASA would like to bring back small items from inside the space station, such as the spacecraft’s bell, log, patched panels and other memorabilia, for display in a museum. These could be brought down by a SpaceX resupply ship in the final year or two of the mission. “Unfortunately, we can’t bring back anything really big,” says NASA’s Ken Bowersox. “Sentimentally, we would love to preserve it somehow.” But the most practical way, he says, is to destructively bring down everything in one go.
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