So now we know what the fate of the International Space Station will be, around the 2030 mark, SpaceX will de-orbit the ISS and it will burn up in the atmosphere creating the most expensive man-made fireball in history, as about 150 billion dollars of hardware will light up the sky over the Pacific Ocean before what’s left of it will crash into the sea at Point Nemo between New Zealand and South America, the place on Earth that is considered to be the farthest from any landmass.
But why is such an expensive and useful object which has been in use continuously for over 20 years going to be crashed into the ocean instead of being saved and what if anything will replace it?
The International Space Station has been at the leading edge of research into how we can live in space for long periods and how it affects us. With exposure to cosmic radiation, bone loss, eye problems, and psychological problems of being cooped up in a small place with other people for months at a time, its given us a good idea of the huge challenges we still face if we are to send humans to places beyond the moon such as Mars and the outer planets.
The International Space Station has also been at the leading edge of research into new medicines, materials, growing food and many, many more that could only be done in zero gravity.
It has also been a bastion of international workings between not only former Cold War enemies The United States and the Soviet Union, now the Russian Federation but also other countries including Canada, the EU through the European Space Agency and Japan.
The ISS has kept countries working together even though they may have had very frosty diplomatic relations elsewhere, this could be seen with the Ukraine conflict. Both NASA and Roscosmos kept working together to keep the ISS up and running when things could have easily gone the other way, although the head of Roscosmos has said that it will submit plans to President Putin to quit the ISS during 2025, but NASA say they have had no such notification and Roscosmos recently said it’s likely they would now carry on until 2028 when Boeings maintenance contract is up for renewal
This is ironic because the ISS came about because of Cold War tensions and the plans of both the US and the Soviet Union to put up their own separate space stations in the 70s, 80s to early 90s.
In the 1970s just as the race to the moon wound down, both the US and the Soviet Union pursued a policy of putting up space stations which was seen as essential even well before the moon missions.
One of the most prominent Proponents of having manned space stations was Werner von Braun, the man who lead the design of the Saturn 5 rockets that took men to the moon with Apollo.
In the 1950s, von Braun and Willy Ley put forward the idea of a rotating wheel space station which would be 76 metres (250 feet) across and contain 3 decks which would revolve at 3 RPM to provide an artificial 1/3 gravity and could hold a crew of 80. One of their ideas was that this would become a waypoint for spacecraft headed to Mars.
But this idea of a rotating wheel was not new and was explored by the Russian rocket scientist Konstantin Tsiolkovsky in 1903 as a way to artificially create gravity.
Now the rotating wheel space station has not come about yet, but in 1959 it was thought that a space station would be the next best thing after the Mercury program until JFK called for the moon landings to beat the Soviets in a loaded race knowing that it would cost the Soviets more that they could afford.
If the Apollo program had not taken place, the Saturn rockets would have been used to lift a space-station into orbit using the upper stages of the Saturn 5 for its structure, just as they were used for the Skylab program after Apollo in 1973.
As it turned out it was the U.S Skylab and the Soviet Salyut stations which would kick off the space station age as interest pivoted from the moon towards a more permanent manned presence in space.
Skylab and Salyut proved the concept would work and led to increasingly longer record-breaking stays in space for the US astronauts and in particular the Soviet cosmonauts.
With increasing cooperation between the US and the Soviets leading up to the 1975 Apollo Soyuz test project which involved the first docking of spacecraft from two different nations and further joint missions were contemplated.
One idea was an international Skylab, this would involve using the backup Skylab B space station which would be visited by both Apollo and Soyuz crew vehicles. This could have later been expanded into a space laboratory by docking the Skylab to the Salyut space station but the idea never got off the ground.
Soon The US would plan for the “Freedom Station” in the 80s and the Soviets, building on their previous efforts would create “Mir 2”.
However, in the USA and Soviet Union, they were having their own internal problems with politics and funding which meant that both were in danger of not being launched at all.
This led to a meeting between American and Russian officials and a plan was put forward to combine their efforts. In 1993 the American vice president Al Gore and Russian Prime Minister Viktor Chernomyrdin announced plans for a new joint space station that would go on to become the ISS.
So from the initial Russin Zarya FGB block module, the ISS now consists of 16 pressurised modules joined together with a total weight of over 400 tonnes and with its solar panels it’s slightly larger than a football field.
So, if the ISS has been up there for over 20 years, with new modules being added here and there from contributing nations and upgrades being done on an almost continuous basis to replace old outdated equipment and things like solar panels, batteries etc all replaced with modern and much more capable version, then why can’t the rest of it be updated.
The problem comes from a number of things but mostly because of its exposure to the sun and the thermal expansion and contraction that it goes through 16 times a day as it orbits the earth every 90 minutes.
Like most aircraft, the structure of the ISS is aluminium and like virtually all metals this is subject to metal fatigue. Aircraft fuselages have a limited lifespan due to the stress of taking off, flying and landing, and the ISS is no different but is subject to far greater temperature range than any earthbound aircraft.
The continuous expansion and contraction of the materials due to the heating and cooling of going from full sunlight and about 120°C, to full shade and -150°C, which change in just a matter of minutes, 16 times a day in the harsh environment of space means can be no room for error.
Sooner or later joins, welds and stress points will begin to fail, not all at once, there will be gradually more and more but it would only take a fracture of one of the main structural points to maybe endanger the crew and require an emergency evacuation. Without replacing the entire structure of the ISS this will only get worse over time and if you going to do tht then you might as well build a whole new system with new better design and materials.
The ISS has grown over the last 20+ years but in a rather haphazard way as modules are developed by different nations rather than working to a specific plan and the design life of the ISS always was about 20 years.
Then there is the problem of atomic oxygen or monoxygen. This is created in the upper atmosphere by the action of the suns UV on normal oxygen molecules which are made-up of two oxygen atoms.
Atomic oxygen is a singular atom of oxygen and is extremely reactive and will bond with most of the structure of the ISS, causing oxidisation, erosion and changes in material strength.
There’s also the issue of micrometeorite impact and space junk from crashed satellites and satellites which have been destroyed on purpose. We have seen instances of small holes puncturing the skin and even cracking the glass of a window in the cupola from orbital debris.
Luckily the ISS flies in a fairly low orbit where the atmosphere is slightly denser and most of these small items which are about the size of a grain of rice or smaller are slowed down enough by the high atmosphere to fall back to earth and burn up.
And this brings us on to another issue. Due to this atmospheric drag, the ISS very slowly also falling back to earth. So it has to be boosted into a higher orbit periodically to prevent it from becoming too low and burning up in the atmosphere.
Some people have said that it should be boosted to a higher orbit so it would be out of the way of most of the atmospheric drag, but this then brings it into the orbit of larger objects of space junk of maybe a centimetre or more across, an impact with something like this could easily punch a hole clean through the ISS and it’s Kevlar protection and cause major damage.
There is also the fact that NASA wants to get out of the business of doing the day-to-day running of a space station and concentrate on deep space exploration and getting humans to places like Mars where things are much more difficult and require a lot more research and development.
NASA wants to offload the replacement for the ISS to a private corporation who will then be paid to construct, launch and look after the new station.
NASA wants to transition from the old ISS to the new station over a period of about two years but if they’re going to do that, they are going have to work quickly to find a replacement and get it designed, built and launched into orbit By 2030.
At the top of list of space station contenders is the Axiom space station, this is backed by the NASA space act agreement or SAA and is due to be built while docked to the ISS and the first two modules have already been manufactured.
Then there is the Orbital Reef, this design is led by Blue Origin and Sierra Space and is also backed by a NASA SAA. This would be launched by Blue Origins New Glenn rocket and then be serviced by Sierra Space’s Dream Chaser spaceplane, although neither of these have yet flown.
Starlab is led by Nano Racks, Voyager Space and Lockheed Martin and would be a commercial space station based around an inflatable main module attached to an orbital science park and is due around 2028.
Northrop Grumman also has a plan for a three-module commercial station to serve sectors including microgravity research, in-space manufacturing and space tourism, again this is backed by a NASA SAA and modules would be based on the Cygnus craft which is used for restocking the ISS with stage one set to launch somewhere in late 2028
So as we can see, there is a final countdown and the clock is ticking and if NASA can’t get its act together the Chinese will be waiting in the wings with their existing space station and they would love to offer its services to the scientific world to prove that they are ready to be the next leaders in space, something that I don’t think would go down well in US political circles.
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