NASA said disassembling and returning to Earth the complete modules and large components that comprise the International Space Station was not feasible.
The space station has not been certified to operate with the SpaceX Starship. There would need to be work and modifications to enable to SpaceX Starship to be authorized to get close and then attach and operate with the Space Station.
Every significant change requires a lot of EVAs, work, money and time.
NASA has examined several options for decommissioning of the International Space Station, including disassembly and return to Earth, boosting to a higher orbit, natural orbital decay with random re-entry, and controlled targeted re-entry to a remote ocean area.
Disassembly and Return to Earth: The space station is a unique artifact whose historical value cannot be overstated. NASA considered this when determining if any part of the station could be salvaged for historical preservation or technical analysis. The station’s modules and truss structure were not designed to be easily disassembled in space. The space station covers an area about the size of a football field, with the initial assembly of the complex requiring 27 space shuttle flights, using the since-retired shuttle’s large cargo bay, and multiple international partner missions, spanning 13 years and 161 extravehicular activities (EVAs), commonly known as spacewalks. 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 EVAs by space station crew, extensive planning by ground support personnel, and a spacecraft with a capability similar to the space shuttle’s large cargo bay, which does not currently exist. Though large modules are not feasible for return, NASA has engaged with the Smithsonian National Air and Space Museum and other organizations to develop a preservation plan for some smaller items from the space station.
Boost to Higher Orbit: NASA evaluated moving the station from its present orbit to a higher orbital regime where its lifetime could be theoretically extended, thereby preserving the spacecraft for future generations. The space station flies at an altitude where Earth’s atmosphere still creates drag and requires regular reboosts to stay in orbit. The station operates in LEO around 257 miles (415 km) in altitude and as a mass of more than 945,000lbs (430,000kg). Depending on solar activity, the station’s orbital lifetime (the time before the station would naturally re-enter from atmospheric drag alone) at this altitude is roughly one-to-two years without reboosts. For this reason, the station cannot remain in orbit indefinitely, as it will naturally fall back to Earth, where an uncontrolled deorbit could pose a threat to people on the ground (see uncontrolled re-entry option).
NASA evaluated orbits above the present orbital regime that could extend just the orbital lifetime of the space station. Boosting the International Space Station would require 120-140 m/s delta-V for a 100-year target orbit lifetime and 760 m/s delta-V for a greater than 10,000 year orbit lifetime, in comparison to 57 m/s for a controlled deorbit.
Why doesn’t NASA plan to repurpose part of the space station for future commercial use or educational purposes such as displaying its modules or parts in a museum?
NASA will assess what internal components on the International Space Station could possibly be used on commercial destinations or returned for display.
After engaging via a Request for Information (RFI) to assess the possibility of reuse of the space station’s major components, NASA received no viable interest from industry. International Space Station modules and major components have a specific power, data and structural architecture which may not be compatible with future platforms. Additionally, disassembly is very complex and costly, with some levels of disassembly being infeasible.
NASA has entered into a contract for commercial modules to be attached to a space station docking port with plans to later detach, and has awarded three space act agreements for design of free-flying commercial space stations.
In addition, much of the structural hardware on station was designed and built in the late 1990s and 2000s. New commercial destinations will benefit from more recent technology advancements.
Preserving the station in a museum presents significant logistical and financial challenges – please see the disassembly and return to Earth section above.
Disassembly and Repurposing in LEO
NASA evaluated reusing or repurposing parts or systems of the space station for reuse since many of these will still have some operational life remaining at deorbit and are already flight proven. Repurposing parts for reuse in LEO poses many of the same logistical challenges as returning it to Earth, including a significant number of EVAs and the r equirement for an in orbit vehicle capable of moving large modules. NASA did not receive any feasible proposals for repurposing parts of the station for commercial use in discussions with U.S. industry.
Boosting to a Higher Orbit
NASA evaluated moving the station from its present orbit to a higher orbital regime where its lifetime could be theoretically extended, thereby preserving the spacecraft for future generations. The space station flies at an altitude where Earth’s atmosphere still creates drag and requires regular reboosts to stay in orbit. The station operates in LEO around 257 miles (415 km) in altitude and as a mass of more than 945,000lbs (430,000kg).
Depending on solar activity, the station’s orbital lifetime (the time before the station would naturally re-enter from atmospheric drag alone) at this altitude is roughly one-to-two years without reboosts. For this reason, the station cannot remain in orbit indefinitely, as it will naturally fall back to Earth, where an uncontrolled deorbit could pose a threat to people on the ground (see uncontrolled re- entry option).
Space station operations require a full-time crew to operate, and as such, an inability to keep crews onboard would rule out operating at higher altitudes.
Ignoring the requirement of keeping crew onboard, NASA evaluated orbits above the present orbital regime that could extend just the orbital lifetime of the space station. If viewed from a perspective of years-in-orbit, the estimated altitudes (depending on solar cycles) could look like this:
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[ maybe it could be an ion thrusters testing assembly(?)
gravity(2013, ?), LLAP ]
The lowest Target Orbital Lifetime of 100 years on the chart is just ~2X the dv and propellant required to de-orbit the ISS and crash it – it is hoped, harmlessly – into the southern Pacific Ocean.
100 years is just a bit more than the entire history of mechanized flight of ANY kind, and space flight is now more than half of that. The floundering of manned spaceflight after Apollo is really obvious and inexcusable. And it’s not even entirely true. The Hubble telescope is 326 miles or 547 kilometers from Earth, yet it was successfully repaired AFTER reaching orbit by the lowly and often-maligned Space Shuttle. 547KM is just 93km-133km below the lowest 100yr orbital target in the chart, and a, say, 50yr orbital target, not charted, would probably be within current technological capabilities and fuel capacities, even with the clearly inferior – for this task – Starship carrying enough fuel in a planned booster rocket or at least one that could transfer fuel to the ISS’s own booster system. Is NASA saying that in 50-100 years they won’t have the capability to boost the ISS again, incorporate it into a larger space station, or even safely disassemble in from a depot in space, possibly with AI controlled robots? The later Star Trek shows & films used AI bots to assemble and repair space-docked (real) Starships. Does NASA’s imagination stop at just NAMING a Space Shuttle Enterprise or can real starships and the space stations to support them still be envisioned?
At the same time as such defeatist, pedestrian options are provided for the ISS, there are ambitious plans for the first atomic rockets from both NASA and private industry, before the end of this decade. Sure, within a 50yr orbital target, these will be feasible, manned or “botted” with AI bots that can make necessary repairs, disassembly, reuse, of the ISS in a larger space station setup. This has been insufficiently explored because we, as a nation, as a species, no longer consider challenging great projects requiring great co-operation (unmentioned is the semi-permanent breakdown of Russian-American co-operation and even the possibility of thermonuclear war ending a lot more than the space program; this is just “accepted” as the background conditions for the NASA TOL chart etc.).
Also unmentioned and maybe even unexamined, is the pollution and ecological damage of throwing a nearly 1 million pound object into the ocean, even assuming something that large can ever be successfully guided to a crash into the ocean, and any ensuing tsunami controlled as well. The history of SpaceX’s first attempts at anything flown into orbit is not inspiring, even if their overall track record is.
Some bean counters are behind this, not anyone with vision, which is apparently in another department at NASA.
I don’t recall JFK’s speech about sending a man to set foot on the moon being a ‘Reasonable” goal. There is Inspirational: the realm of leadership. And then there is Reasonable: the realm of bean counters and cowardly bureaucrats. IMHO.
So, the station is currently at an altitude where the probability of being hit is lower than any higher altitude below 1,900 km. And it’s easily accessible at it’s current altitude.
Missing is any analysis of the yearly delta V budget to just keep it in its current orbit. But we’re told that without station keeping, it would naturally deorbit in about 18 months, so we can reasonably estimate it at about 40m/s per year.
Required station keeping thrust isn’t a function of mass, of course, but instead frontal area. And SpaceX is planning an orbital fuel depot, while Starships have an area comparable to the station.
Sounds like the simplest thing would be to move it to the fuel depot orbit, and just let it “draft” the depot.
Of course, we all know that when a bureaucracy has its heart set on a course of action, it is careful to only evaluate options that are inferior to that course…
Thanks for reporting this. Nasa’s getting a lot of flack for paying to destroy the ISS, but the truth is that they’ve really done a lot of research into all the possibilities, be they boosting it, selling it, disassembling it for parts. After looking through all of those, they determined that destroying it was the most reasonable option.