After more than three decades in service, the International Space Station (ISS) is expected to retire in 2030. However, we can’t just abandon this massive football stadium-sized structure in the space. It is the second largest and heaviest object orbiting our planet (after the moon) and if anything hits it, it could be destroyed in low orbit generating millions of debris that could jeopardize future space missions.
Therefore, it will be destroyed in a controlled manner right after retirement. For this task, NASA has awarded SpaceX a whopping $843 million contract. SpaceX will develop the US Deorbit Vehicle, a spacecraft that will guide the ISS into Earth’s atmosphere.
“While the company (SpaceX) will develop the deorbit spacecraft, NASA will take ownership after development and operate it throughout its mission. Along with the space station, it is expected to destructively break up as part of the re-entry process,” NASA notes.
ISS’s demise will mark the end of an important era in human space history. The first module was launched in November 1998 and became operational in November 2000. In the last 24 years, it has hosted 280 astronauts from 23 countries, serving as a hub for global collaboration aimed at advancing space research and innovation.
“What the ISS has provided over the last 23 years is a platform to carry out a wide variety of experiments with a rapid turnover that simply cannot be carried out on the ground. It has also fostered international cooperation and inspired many into studying science further,” Darren Baskill, an astrophysicist from the University of Sussex, told BBC Science Focus.
Is destroying the ISS our only option?
ISS is a 430-ton structure, so dragging it into Earth’s atmosphere is a tedious and complex task. But why don’t we push it above to a higher orbit where it remains stable? Well, this is something that NASA also considered but rejected because of the risk of space junk.
The logistics and other requirements for such a mission are also more challenging than atmospheric re-entry. This is because when an object is nudged toward Earth, our planet’s gravitational pull is there to help, but when it comes to pushing an object away in a particular direction, we’re completely on our own.
Another option is to dismantle the ISS and bring it piece by piece to Earth. However, according to NASA, such a mission would be financially unviable and could also end up risking the lives of astronauts involved in the dismantling process.
However, the space agency will try to bring some small items from the ISS as souvenirs. They will be displayed in a museum for the public.
“Unfortunately, we can’t bring home really, really big stuff. The emotional part of me would love to try and save some, but the most practical approach is to bring everything down in one destructive stroke,” Ken Bowersox, associate administrator for space operations at NASA, said.
How will SpaceX’s Deorbit Vehicle work?
SpaceX currently uses the Dragon capsule to carry astronauts and cargo to the ISS. It has eight engines and a fuel tank capacity of 3,300 kg. The company will provide NASA with a modified version of this spacecraft for ISS’s reentry into Earth.
The modified Dragon capsule will have 46 engines and a 16,000 kg fuel tank. It will be launched one and a half years before ISS’s retirement. The astronauts aboard the station during that time will leave it for good six months before the ISS will be removed from orbit.
When the ISS is at a distance of 136 miles from Earth’s surface, the Dragon capsule will act like a tugboat, using its thrusters to push the space station out of orbit and into Earth’s atmosphere.
However, since the ISS is a large structure (measuring 356 feet from one end to the other) some parts will survive the burn. The US Deorobit vehicle will guide the station such that its remaining pieces fall into the ocean — a safe bet would be Point Nemo, the most isolated place in the world and the farthest point from a landmass.
“Selecting a U.S. Deorbit Vehicle for the International Space Station will help NASA and its international partners ensure a safe and responsible transition in low Earth orbit at the end of station operations. This decision also supports NASA’s plans for future commercial destinations and allows for the continued use of space near Earth,” Bowersox said.
