Astronauts and cosmonauts have continuously occupied the International Space Station (ISS) since its launch in 2000, orbiting Earth every 90 minutes.
During its tenure, the floating laboratory was a melting pot for scientific experiments, long-duration space travel research, and international collaboration. So far, 280 astronauts representing at least 23 countries have gone to the station.
Still, as they say, all good things must come to an end. And so now, at the end of the decade, the ISS will reach the end of its functional life.
But what to do with a space station the size of a football field weighing 430 tons when it is no longer in use?
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You can’t just abandon ship; after the Moon, the ISS is the largest object orbiting the Earth. If it hit something, the whole thing could fall apart, creating a shower of debris that would threaten other satellites.
How about moving it a little higher so it doesn’t get in the way? It’s out of the question, although NASA considered it.
“The space station is a unique artifact whose historical value cannot be overstated. NASA considered this when determining whether any part of the station could be salvaged for historical preservation or engineering analysis,” the agency wrote in a white paper.
Ultimately, however, such an undertaking was deemed too costly and complex to carry out.
That leaves us with one option for this groundbreaking feat of human ingenuity: total destruction.
Enter Elon Musk, or rather his now-dominant company SpaceX, which officially won a contract from NASA on June 26 to develop and supply an ISS funeral home — an $843 million job for a private enterprise.
“The selection of America’s Deorbit vehicle for the International Space Station will help NASA and its international partners ensure a safe and responsible transition to low Earth orbit at the end of the station’s operation,” said Ken Bowersox, associate administrator for the Mission Directorate for Space Operations at NASA Headquarters in Washington, said in declaration.
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Although plans have not yet been finalized, the basic idea is that the Deorbit Vehicle will act as a towboat and pull the ISS down into the atmosphere, where much of it will burn up on re-entry.
However, the sheer size of the ISS means that parts of it will almost certainly survive the onslaught of heat. Care must therefore be taken to ensure that any parts that reach the surface do so in an uninhabited area.
“Most of the Earth is covered in water and space scientists are well versed in applying changes to the orbit of satellites up to the point of re-entry to precisely control the trajectory of a spacecraft,” said Dr Darren Baskill, lecturer in astronomy at the University of Sussex, says BBC Science Focus.
Baskill explains that the whole process will involve fine adjustments during the final ISS orbits, so scientists can almost guarantee that it will end up in the right place, away from humans.
“To use a sports analogy, rocket science is more curling than a penalty kick in soccer, where adjustments are made along the entire path of the shot,” he says.
There is precedent for this. On March 23, 2003, the Russian space station Mir crashed at Point Nemo in the Pacific Ocean. At a distance of 2,688 kilometers from the nearest land, the same location is a safe bet for where the ISS will also be stored.
Is this the end of our interstellar life?
With the ISS’s days numbered, this is the first time in more than two decades that humans will not be permanently present on the station. To put it into perspective, there are now fully grown adults who have literally never gone a day without someone whistling over the ISS.
Of course, humans will still be up there in space. Unbeknownst to many in the West, China has had its own Tiangong space station in orbit since 2021 and hopes to keep it operational until the 2030s.
As for the US-backed station, NASA is looking to the private sector to house its astronauts more cheaply in the post-ISS era.
For example, the Commercial Low Earth Orbit Development (CLD) program was introduced by NASA in 2021, with hundreds of millions of dollars available to companies capable of developing new space stations. It sounds expensive, but given that the ISS cost about $150 billion to develop and $4 billion a year to operate, this move could turn out to be quite a savvy one.
Besides, geo-orbits are old news. Much more ambitious is NASA’s Lunar Gateway project, which, if successful, will launch a space station into orbit around the moon (no points for guessing). With any luck, the first astronauts will enter the gate in 2028.
In short, the end of the ISS reign in low orbit brings with it uncertainty about the future of space habitation. It will almost certainly be controlled by the private sector and we will probably see us spread our wings beyond our planet.
“What the ISS has provided over the past 23 years is a platform to perform a wide variety of rapid-turnover experiments that simply cannot be performed on the ground,” says Baskill. “It has also encouraged international collaboration and inspired many to further study science.”
As Bowersox says, “The orbiting laboratory remains a blueprint for science, exploration and partnership in space for the benefit of all.”
About our expert
Darren Baskill is Head and Lecturer in the Department of Physics and Astronomy at the University of Sussex. He previously lectured at the Royal Observatory Greenwich, where he also initiated the annual Astronomy Photographer of the Year competition.
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