SpaceX has been ordered to deorbit the International Space Station (ISS) when its operations are over. On Wednesday, the company and Nasa announced their plan to safely eliminate this huge satellite by directing it towards a controlled re-entry into earth’s atmosphere and eventually sinking the remaining parts in the sea. The targeted date of such mission is early 2031, which coincides with space station’s 32nd year in orbit.
According to Nasa, there were alternative choices that included disassembling the station, shipping it back down or handing over ownership to someone else. However, an assessment made concluded that controlled deorbit was the best way of retiring NASA from ISS. To do this complex task however required NASA spending up to $843 million on SpaceX who are recognized as experts on space operations.
Originally launched in 1998 with its main components put together two years later when astronauts moved into it; the International Space Station—built through international cooperation among Russia, United States of America, Europe, Japan and Canada—has since shown its age signs. It gradually expanded over time until now covering about 5 acres equivalent. Also weighing nearly 1 million pounds or even more than 430000 kilograms close to that of a football field.
In line with private firms’ future launches of their own stations expected by at least 2030 while NASA believes ISS will still be operational up until then; under these plans Nasa is one customer among many just as it does for station cargo and crew deliveries. This strategy will allow Nasa to focus more on lunar/Martian explorations.
The lifespan of current research may be prolonged if all commercial outposts fail to come online by 2030 according to Nasa. The idea here would be that there should be some time overlap between this station and future company facilities in order not interrupt ongoing scientific studies.
Nasa has chosen not to dismantle the space station and ship pieces back to earth. It is also out of the question that private firms could retrieve the parts for their intended outposts. The agency has explained that construction in space was not meant for ISS and therefore this option would be expensive and unsafe for astronauts who would have to help in taking down the station. Additionally, there aren’t currently any spacecraft big enough like Nasa’s retired shuttles which can return all the components.
Alternatively, NASA might have considered pushing the uninhabited space craft up higher into a safer orbit but it too was rejected due to logistical challenges associated with it and increased risks of adding more space debris. Consequently, NASA has decided that the ISS will stay put until another idea is discovered as deemed necessary.
The International Space Station (ISS) is situated at about 420 kilometers above Earth in orbit and its altitude is maintained by occasional boosts from visiting ships preventing it from decaying. If left unattended, this satellite would gradually lose height until it fell back into Earth’s atmosphere uncontrollably leading to burning up on re-entry. In order for a safe, controlled reentry NASA will steer them towards areas over Indian or South Pacific oceans where they can fall and harm no living person.
Nasa estimates that some denser elements, ranging from “a microwave oven” “to a sedan”, will make it through the reentry and form a narrow debris field stretching 1,200 miles. At first, Nasa and its partners considered using three Russian supply ships for deorbiting process. However, it became obvious that a more capable spacecraft was required. Thus, Nasa invited proposals from industry while in June gave SpaceX the contract of developing a dedicated deorbit vehicle.
SpaceX is planning to use one standard Dragon capsule similar to those used for supplying the station and transporting astronauts to it but with an enlarged trunk. This redesigned trunk will contain a record forty-six engines and carry over thirty-five thousand pounds of fuel.
According to Sarah Walker working at SpaceX; creating such spaceship has been very hard because ensuring that it can maintain control of space station while facing increasing atmospheric drag during final descent stage.
Due to the unique requirements of the spacecraft, Nasa said that an extremely powerful rocket would be needed for orbital insertion. The capsule should enter orbit one year before its closure date. Astronauts will stay on board as the station is gradually lowered down towards lower altitudes. Six months before destruction of the station, crew members will abandon it and head back home.
When Dragon capsule reaches approximately 137 miles above sea level (220 km) then Station starts losing altitude in four days’ time.
In 1979 Australia and parts of nearby Pacific Ocean were covered by debris when Skylab, NASA’s inaugural space station came crashing down on Earth. One of the initial missions like space shuttle could have attached a rocket onto Skylab thus directing its decline or raising its orbit as per their plans. However this shuttle was not ready in time as it only made its maiden flight in 1981. Mission control guided a gradual tumble into Skylab’s trajectory targeting Indian Ocean hence there were also fragments which reached Western Australia.
Russia is more experienced in handling space station reentry. Mir was deliberately crashed into the Pacific Ocean in 2001 after being operational for fifteen years. Numerous Salyut stations also met similar ends before Mir.
Nasa has expressed a goal to return any objects kept within the spacecraft from orbiting for display in museums. Among them are ship’s bell, logs, patch adorned panels and other mementos. SpaceX supply ships will be used to bring these artifacts back to Earth during the final 1-2 years of the station’s life.
The official at Nasa known as Ken Bowersox referred to this approach as being “limited” admitting that, “we can’t bring home really, really big stuff.” Furthermore he admitted that while his sentimental side might want to try keeping some larger pieces intact his most practical decision would be reducing everything with one destructive event.
