CAPE CANAVERAL- SpaceX will use a powerful, upgraded capsule to launch the International Space Station out of orbit when the space station reaches the end of its useful life.
NASA and billionaire Elon Musk’s SpaceX company on Wednesday outlined a plan to burn up the space station as it reenters Earth’s atmosphere and submerge the remains in the ocean, ideally starting in 2031, when it turns 32. NASA has rejected other options, such as dismantling the station and bringing everything back, or leaving the station in the care of someone else.
NASA has awarded SpaceX a $843 million contract to shoot down the ISS, the largest structure ever built outside the planet.
Why dismantle the space station?
The International Space Station is already showing signs of aging. Russia and the United States launched the first pieces in late 1998, and astronauts boarded it two years later. Europe and Japan added their own segments, and Canada contributed robotic arms. By the time NASA’s shuttles were retired in 2011, the station was the size of a football field and weighed nearly 430 tons (1 million pounds).
The space agency estimates that the station will be useful at least until 2030. The goal is for private companies to launch their own space stations by then, with NASA being one of its many customers. That strategy — already used to transport cargo and crew to the station — will allow NASA to focus on trips to the Moon and Mars.
The agency could also decide to extend the station’s life if there is no privately operated station by then. The goal is to allow for overlap between the International Space Station and new operations so that scientific research is not interrupted.
Why not bring her back to Earth?
NASA considered dismantling the space station and transporting the pieces back to Earth, or letting private companies reuse the parts for stations they plan to build. But dismantling the station in orbit was never considered, according to the space agency, because any attempt to do so would be expensive and risky for the astronauts operating the operation.
There is also no spacecraft the size of NASA’s older shuttles to carry the components down. Another option would be to lift the empty station into a higher, more stable orbit, but that too has been ruled out given logistical problems and the growing risk posed by space junk.
How will it be brought to Earth?
Visiting spacecraft periodically boost the space station to keep it in orbit at about 260 miles (420 kilometers) above the surface. Otherwise, it would plummet ever lower into an uncontrolled nosedive. NASA wants to ensure it reenters safely and splashes down in a remote area of the South Pacific or possibly the Indian Ocean, which would require launching a spacecraft to dock with the station and steer it toward its watery grave.
NASA expects some of the densest pieces, ranging in size from a microwave oven to a sedan, to survive in a narrow, 1,200-mile (2,000-kilometer) debris field. NASA and its partners considered using three Russian supply ships, but a more robust craft was needed. So a competitive bidding process was held, and in June, SpaceX won the contract to produce a deorbiter craft that will lift the ISS out of orbit.
What will the deorbit spacecraft look like?
SpaceX plans to use a regular Dragon capsule — the kind it typically uses to ferry supplies and astronauts to the space station — but with a much larger engine bay that will hold a record 46 engines and more than 35,000 pounds (16 tons) of fuel. SpaceX’s Sarah Walker said the challenge will be creating a spacecraft powerful enough to guide the space station while also withstanding the tugs and forces generated by increased atmospheric drag during the final descent.
The spacecraft will require an especially powerful rocket just to get into orbit, NASA said. The capsule would launch a year and a half before the station’s expected demise. Astronauts would remain on board as it gradually descends. Six months before the ISS’s destruction, the crew would abandon the ship and return home. Once the station has descended to about 137 miles (220 kilometers) in altitude, the Dragon capsule would return it to Earth four days later.
Has this been done before?
NASA’s first space station, Skylab, crashed down in 1979, showering debris over Australia and the surrounding Pacific. NASA had hoped that one of the first space shuttle crews could attach a rocket to control Skylab’s descent or boost its orbit. But the shuttle wasn’t ready by then; its first flight didn’t take place until 1981.
Ground controllers managed to slowly lower Skylab into the Indian Ocean. However, some fragments also fell over western Australia. Russia has more experience with re-entry of space stations. Mir operated for 15 years before being guided into re-entry over the Pacific Ocean in 2001. Before that, several Salyut stations had been destroyed.
Will anything be saved?
NASA wants to bring back some small items from inside the space station for museum display, such as the ship’s bell and logs, patch panels and other memorabilia. Those items could be flown down on SpaceX supply ships in the final year or two. “Unfortunately, we can’t bring back very, very large things,” said NASA’s Ken Bowersox. “The sentimental side of me would love to try to salvage something,” but the more practical approach is to knock everything down in one destructive blow, he added.
Source: With information from AP
