In 23 years of honorable career, the International Space Station has hosted over 200 astronauts, and almost four thousand experiments that have led to over 500 research studies published in scientific journals. But nothing is destined to last forever. And the ISS is no exception: NASA and ESA have shifted their attention to the Lunar Gateway that will soon begin to be built in lunar orbit, and this means that the elderly station that orbits our planet now has its days numbered. As decided by the consortium of space agencies that manage the station, the “decommissioning” will be entrusted to SpaceX, which recently revealed the details of its $843 million plan (this is the amount put forward by NASA) to send the station to crash safely into the ocean.
With 6x more propellant and 4x the power of today’s Dragon spacecraft, SpaceX was selected to design and develop the US Deorbit Vehicle for a precise, controlled deorbit of the @Space_Station https://t.co/GgtuplTwqQ pic.twitter.com/E23sS7CE4U
— SpaceX (@SpaceX) July 17, 2024
Why it should be brought back
The ISS orbits just over 400 kilometers from the surface of our planet, a height at which it is subject to the friction produced by the Earth’s atmosphere (still present, despite being extremely thin at such a distance) and is therefore destined to fall, slowly but inexorably, onto our planet. In the absence of external intervention, this would happen in one or two years. And to avoid this, it is necessary to periodically intervene with the station’s thrusters, to readjust its orbit. For this reason, once its usefulness is over, it is not possible to simply abandon the structure where it is located: it would fall inexorably into the atmosphere, in a dangerous uncontrolled reentry that would put things and people on the surface at risk, given the size of the station and its weight of almost 430 tons, which would almost certainly determine the arrival on land (or in the sea) of large debris.
The role of SpaceX
In recent years, NASA and the other space agencies responsible for the station have considered various solutions to secure it at the end of its operational life, such as dismantling it in space or pushing it into a more external orbit, where it could remain for centuries without the need for external intervention. In the end, the most cost-effective plan turned out to be to create a vehicle capable of reaching the station and then pushing it into a safe reentry orbit, which would drop all the debris that is not vaporized by friction with the atmosphere into the ocean.
A vehicle like this doesn’t exist at the moment, which is why SpaceX has been given the task of building it. The project, revealed in recent days, is to modify one of the Cargo Dragon capsules currently used to refuel the ISS, adding 30 extra engines (for a total of 46), doubling its length, and quadrupling its power. With such a vehicle, it will be possible to hook onto the space station, push it out of its orbit, and guide it to the chosen reentry point. When will this happen? There is still no official date, but NASA has said that the ISS will continue to be used regularly for several more years, and that its “decommissioning” should take place no earlier than 2030.