An Extremely Detailed Analysis of How NASA Plans to Destroy the ISS

The International Space Station (ISS) is counting its days, and the orbiting laboratory is set to retire in a few years. For more than 20 years, the space station has served as a base for astronauts in low Earth orbit, but it will soon meet its end as it plunges into the atmosphere, leaving behind tiny fragments of an iconic legacy.

NASA is preparing a plan to deorbit its beloved space station in 2030, sending it flying into Earth’s atmosphere where most of its contents will burn up from the heat of reentry. The space agency, working with its international partners, has studied several different options and narrowed down its choices based on feasibility and cost. After years of effort, NASA has decided to tap private industry to design a spacecraft that will drag the space station to its fiery demise.

The ISS is a big guy, holding the record for the largest human-made structure in space. It spans 350 feet (109 meters) long (about the size of a football field) and will be the largest object ever to be de-orbited. Bringing the ISS down won’t be easy, and the main challenge is ensuring that its remaining parts land far from populated areas. Here’s a look at how NASA and its partners plan to return the historic space station to its final resting place.

Why is NASA abandoning the ISS?

NASA and its partners began assembling the space station in 1998. The ISS has served as a central platform for scientific research and demonstrations of new technologies in microgravity that have often been used on Earth. The space station symbolizes international cooperation and peace, showcasing collaboration among space agencies from the United States, Russia, Europe, Japan, and Canada. It has hosted hundreds of astronauts from 18 different countries, who have conducted more than 270 spacewalks.

Alas, all good things must come to an end. The ISS is aging, and the wear and tear of space travel has taken its toll. Significantly, its decommissioning will give way to the commercial use of low Earth orbit, with private companies designing their own space stations to take over once the ISS is gone.

Russia has agreed to continue deploying its cosmonauts to the ISS until 2028, while it builds its own space station in orbit. Since its creation, the ISS has hosted at least one NASA astronaut and one Roscosmos cosmonaut at any given time. Over the years, Russia’s Soyuz and Progress spacecraft have flown numerous crewed and cargo missions to the ISS. The Russian space agency will likely take those toys with it when it leaves, meaning NASA will be without its key ISS partner for the task of dismantling the ISS.

The space station will have to be destroyed because disassembling it is simply not feasible. “The station was never designed to be disassembled again,” Marco Langbroek, a professor of astrodynamics at Delft University of Technology in the Netherlands, told Gizmodo via email. “I think the current plan is the only possible option.”

The initial assembly of the space station took 27 missions aboard NASA’s now-retired space shuttle. Disassembling the ISS piece by piece would require a massive effort by NASA, international space agencies and their astronauts, as well as having a spacecraft large enough to bring those pieces back to Earth.

“Any disassembly effort to safely disconnect and return individual components (such as modules) would face significant logistical and financial challenges, requiring at least an equivalent number of spacewalks by the space station crew, extensive planning by ground support personnel, and a spacecraft with a capacity similar to the large payload bay of the Space Shuttle, which does not currently exist,” NASA wrote in a recent report.

The space agency added that it is developing a preservation plan for some of the smaller objects on the ISS. This makes perfect sense: the station is full of memories and artifacts that deserve to be preserved.

The path to destruction

Rather than let the space station crash back to Earth in an uncontrolled reentry, NASA and its partners will need to choose a remote, uninhabited area of the ocean as a landing site for the remaining debris. Standard practice for orbital debris mitigation considers the risk of human casualties to be less than 1 in 10,000.

Before deorbiting, the ISS will be emptied of all transportable objects that can be brought back to Earth. ISS astronauts will also have to evacuate the space station before it deorbits, leaving the orbiting laboratory empty for the first time in decades. Someone—we don’t know who, of course—will be the last astronaut floating in its cozy confines.

A controlled reentry always begins with a spacecraft’s orbit being lowered. The first step will be to cancel the periodic firings that keep the lab hovering about 400 kilometers above sea level. Eventually, the station’s orbit will drop to less than 250 kilometers, Langbroek said. This natural orbital decay, caused by atmospheric drag, will likely take months to gradually lower the ISS, he said.

The SpaceX Factor

For the next step, the space agency has tasked SpaceX with designing a new deorbit vehicle. That vehicle will dock with the ISS and perform a series of deorbit launches to lower the space station’s orbit even further. (NASA had previously suggested using Russia’s Progress cargo ship to deorbit the ISS, but that idea is no longer on the table.) In March, the space agency released its 2024 budget proposal, which included $180 million to develop a deorbit capability for the ISS by the end of 2030. At the time, NASA estimated that its ISS tug would cost about $1 billion in total.

The contract recently awarded to SpaceX is worth $843 million, which will cover the vehicle’s development but does not include the cost of launching it. The company has not released details about the design of its space tug, and it’s unclear whether it might reuse its Dragon spacecraft or build a new one entirely. The exorbitantly priced tug is a single-use spacecraft and will not survive the deorbit mission. While SpaceX “will develop the deorbit spacecraft, NASA will take ownership of it after development and operate it throughout its mission,” NASA wrote. “Like the space station, it is expected to destructively disintegrate as part of the atmospheric reentry process.”

Safe and controlled reintegration

With the help of its brand-new tug, the ISS will need to execute a significant thrust to precisely target its reentry point. This will ensure a controlled descent through the atmosphere to manage its debris footprint. The thrust maneuver must be strong enough to put the spacecraft into an elliptical orbit, or an oval-shaped trajectory, so that it is properly captured by the atmosphere, according to Tobias Lips, managing director of satellite aerodynamics company Hyperschall Technologie Göttingen in Germany.

“If you have a maneuver that is powerful enough to bring your perigee (minimum altitude) down to zero, then the uncertainties about the distribution of your fragments on the ground play a smaller role,” Lips told Gizmodo. “If you accept a higher perigee altitude, then the potential splashdown area, which includes all the uncertainties, becomes larger and larger.”

According to reentry experts, about 40% of the ISS will survive its trip through the atmosphere, but NASA will have sufficient control over the splashdown area. While a significant amount of material could fall from space, it is unlikely that it will land near inhabited areas.

Destruction of an icon

The ISS will hit the atmosphere at a speed of 28,000 km/h. Once the space station descends to an altitude below 100 km, it will begin to disintegrate, according to Langbroek. During its fatal fall, the famous structure will begin to deform, its familiar silhouette beginning to disintegrate piece by piece, the metal bending under the pressure.

“Exterior elements like solar panels and antennas will likely break first, and then the main structure of the station will shatter into fragments,” Langbroek said. “Most of them will burn, but some denser, more massive parts, like the docking ports and parts of the truss structure, will likely survive.”

The parts of the ISS that will survive reentry will likely make up between 10 and 20 percent of its total mass. That’s over 180,000 pounds of material, which is why a controlled reentry is essential. This may seem obvious, but the smaller the spacecraft, the fewer fragments will survive reentry. As Lips explains, smaller objects heat up more intensely and are more likely to disintegrate upon reentry due to their compact size, while larger objects are less likely to completely break up, making it harder for them to completely disintegrate.

The remaining fragments of the ISS will land in a deserted area of the southern Pacific Ocean called the Spacecraft Graveyard, home to many dead satellites (including the Russian space station Mir, which crashed to Earth in 2001). This remote area of the Pacific Ocean, called Point Nemo, lies between New Zealand and South America and is the furthest point from land.