The International Space Station (ISS) is counting down its days, with a retirement atop the orbiting laboratory in just a few years. For more than 20 years, the space station has served as a home for astronauts in low Earth orbit, but it will soon face its demise as it plunges through the atmosphere to leave behind small fragments of an iconic legacy.
NASA is preparing a plan to de-orbit its beloved space station in 2030, sending it flying through Earth’s atmosphere, where most of it will burn up in the heat of re-entry. The space agency, along with its international partners, has considered several different options and narrowed it down based on feasibility and cost. After years of effort, NASA decided to call on private industry to design a spacecraft that would tow the space station to its fiery demise.
The ISS is a big boy, holding the record for the largest man-made structure in space. It stretches 357 feet (109 meters) long – about the size of a football field – and will be the largest object ever to leave orbit. The fall of the ISS will not be easy, and making sure that its remaining parts land away from inhabited areas is the main challenge. Here’s an overview of how NASA and its partners plan to take the space station to its final resting place.
Why is NASA scrapping the ISS?
NASA and its partners began assembling the space station in 1998. The ISS has served as a major platform for scientific research and demonstrations of new technology in microgravity that are often used on Earth. The space station symbolizes international cooperation and peace, featuring cooperation between the space agencies of the US, Russia, Europe, Japan and Canada. It has hosted hundreds of astronauts from 18 different countries, who have completed over 270 spacewalks.
Alas, all good things must come to an end. The ISS is aging and the wear and tear of being in space has taken its toll. Significantly, its retirement will pave the way for 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 as it builds its own space station in orbit. Since its inception, the ISS has continuously hosted at least one NASA astronaut and one Roscosmos cosmonaut. Over the years, the Russian Soyuz and Progress vehicles have carried out numerous crew and cargo missions to the ISS. The Russian space agency will likely take these toys with it when it leaves, meaning NASA will be without its key ISS partner for the dismantling task.
The space station will have to be destroyed, as its dismantling is simply not practical. “The station was never designed to detach again,” Marco Langbroek, a lecturer in astrodynamics at Delft Technical University in the Netherlands, told Gizmodo in an email. “I think the current plan is the only option available.”
The initial assembly of the space station took 27 missions using NASA’s now-retired space shuttle. Taking apart the ISS bit by bit would require a huge effort by NASA, the international space agencies and their astronauts, in addition to having a spacecraft big enough to return those pieces to Earth.
“Any decommissioning effort to safely separate and return individual components (such as modules) will 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 capability similar to the large space shuttle cargo bay, which currently does not exist,” NASA wrote in a recent report.
The space agency added that it is in the process of developing a storage plan for some smaller items from the ISS. This makes a lot of sense; the station is filled with memorabilia and artifacts worth preserving.
The road to destruction
Instead of letting the space station fall toward Earth in an uncontrolled reentry, NASA and its partners will have to target a remote uninhabited area in the ocean as a landing point for any remaining debris. Standard orbital debris mitigation practice accepts a human casualty risk of less than 1 in 10,000.
Before the deorbit process takes place, the ISS will be emptied of all movable cargo that can be transported back to Earth. ISS astronauts will also have to evacuate the space station before its deorbit, leaving the orbital laboratory empty for the first time in decades. Someone – obviously we don’t know who – will be the last astronaut to swim within its cozy confines.
A controlled reentry always begins with the descent of a spacecraft into orbit. The first step to reentry will be to cancel the periodic orbit-raising burns that maintain the lab’s position about 250 miles (400 kilometers) above sea level. Eventually, the station’s orbit will fade to below 150 miles (250 kilometers), according to Langbroek. This natural orbital decay, caused by atmospheric drag, would likely take months to gradually bring down the ISS, he explained.
The SpaceX factor
For the next step, the space agency has commissioned SpaceX to design a new deorbit vehicle. This vehicle will dock with the ISS and perform a series of deorbit burns to further lower the space station’s orbit (NASA had previously suggested using the Russian Progress cargo ship to deorbit the ISS, but this is now off 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 had estimated that its withdrawal from the ISS would it cost about 1 billion dollars in total.
The recently awarded contract with SpaceX is worth $843 million, which will cover the development of the vehicle, but does not include the cost of its launch. The company hasn’t shared details of its space shuttle design, and it’s unclear whether it might reuse its Dragon spacecraft or build another one altogether. The high-priced attractor is a one-off spacecraft and will not survive the deorbit assignment. While SpaceX “will develop the deorbit spacecraft, NASA will take ownership after development and operate it throughout its mission,” NASA wrote. “Along with the space station, it is expected to break apart destructively as part of the re-entry process.”
Safe and controlled re-entry
With the help of its brand new tow, the ISS will need to execute a large re-entry burn to precisely target its re-entry location. This will provide a controlled descent through the atmosphere to manage its debris footprint. The thrust maneuver must be strong enough to bring the spacecraft into an elliptical orbit, or oval-shaped path, in order to be properly captured by the atmosphere, according to Tobias Lips, managing director of the satellite aerodynamics company Hyperschall Technologie Göttingen. in Germany.
“If you have a maneuver that is strong enough to bring your perigee [minimum altitude] to essentially zero, then the uncertainties of your fragment distribution on the ground play a smaller role,” Lips told Gizmodo. includes all the uncertainties, it gets bigger and bigger.”
The reentry expert estimates that about 40% of the ISS will survive its hot journey through the atmosphere, but that NASA will have enough control over the fallout zone. While a significant amount of material may fall from space, it likely will not land near inhabited areas.
Destruction of an icon
The ISS will crash into the atmosphere at speeds reaching 17,500 miles per hour (28,000 kilometers per hour). Once the space station descends to an altitude below 60 miles (100 kilometers), it will begin to disintegrate, according to Langbroek. During its fatal nose, the famous structure will begin to distort, its familiar outline will begin to disintegrate piece by piece, with the metal bending under the pressure.
“External elements such as solar panels and antennas will probably be detached first, then the main structure of the station will be broken into fragments,” said Langbroek. “Most of them will burn, but some important denser and more massive parts, such as the mooring gates and parts of the truss structure, are likely to survive.”
The parts of the ISS that survive reentry are likely to account for 10% to 20% of its total mass. That’s over 180,000 pounds (81,646 kilograms) of valuable material, which is why a controlled re-entry is essential. This may seem obvious, but the smaller the spacecraft, the less fragments survive reentry. As Lips explained, smaller objects heat up more intensely and are more likely to disintegrate upon reentry due to their compact size, while larger objects are less prone to complete decay, making it difficult for them to complete dissolution.
The remaining fragments of the ISS will be scattered in an empty area of the South Pacific Ocean known as the spacecraft graveyard, with many dead satellites buried at the bottom (including Russia’s Mir space station, which crashed to Earth in 2001 ). The remote region of the Pacific Ocean, called Point Nemo, lies between New Zealand and South America and is the farthest place from dry land.
Related article: Skylab, the first US space station, changed what we thought was possible in orbit
In 1979, the first American space station, Skylab, broke up and disintegrated in Earth’s atmosphere, scattering debris across the Indian Ocean and Western Australia. NASA calculated that there was a 1 in 152 chance that the remaining fragments would hit people on earth. Fortunately, no injuries were reported.
It’s hard to think of the beloved ISS dismembered and trashed in the Pacific Ocean, but its legacy will outlast its charred fragments. The destruction of the space station signals the end of an era and marks the beginning of a new one that leans more toward the commercialization of space. With this new era, the Earth’s orbit will undergo significant changes.
Correction: An earlier version of this article gave the incorrect year for Skylab’s reentry; it was in 1979, not 1973.
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