Comparing ISS 2012 config to original plans

Not open for further replies.


Now that assembly of the International Space Station is nearing completion, I thought it would be of interest to note what the original planned configuration called for compared to actual 2012 assembled station.

The U.S. side is derived from what was to be Space Station Freedom and the Russian side is derived from what was to be Mir 2. The Japanese Kibo modules of today's ISS is unchanged and are exactly the same as what they planned for Freedom. The US and ESA lab modules on Freedom were to be as large as Kibo's main lab module. Late in the planning stages of Freedom, tight budgets for both NASA and ESA forced the agencies to scale-down and redesign their respective lab modules.

Of course, we all know that Russia merged Mir 2 with Space Station Freedom. The Russian Zvezda module was already under construction as was planned as the Mir 2's cornerstone. Before the ISS program, other Mir 2 modules remained mostly unfunded. As part of the treaty creating ISS, the US agreed to fund what would have been the second Mir 2 module - Zarya. In exchange, the US took ownership of that module. Russia over-charged the US for that module enough to create a 'spare' and the pressurized section of what had been planned as a solar energy module platform. When Russian funds ran out, the Zarya 'spare' and the pressurized section for the solar platform sat in storage. Years later, Russia began incrementally increasing their space budget and work restarted on Russian modules. The Zarya spare is being converted to a module that will launch early 2012 and the pressurized section of what was to be the solar platform was converted to MRM-1 that was just delivered to station by Atlantis.

On Freedom, there were originally 4 node modules planned. The Unity module on ISS is exactly the same as what was planned as the Freedom nodes. Faced with an increasingly shrinking budget, NASA was forced to plan for 2 nodes on ISS (instead of 4). But even 2 nodes became doubtful as ISS development began to mature. With Node 1 completed, the next node - Node 2 - was just a shell – and NASA would need more money from Congress to finish it. The US Hab module – scaled down from its original Freedom design - suffered the same fate as Node 2 – a shell with no funds for outfitting.

With no additional funding from Congress to finish Node 2 and Hab, NASA decided to barter with the Italian Space Agency (which wanted to be a big player in the ISS program). In return, the ISA would contribute 2 node modules (known today as Harmony and Tranquility) for the ISS. Both modules were to be 2/3 larger than the planned US-manufactured nodes (including Unity, Node 1). NASA terminated its contract with Boeing for the completion of Boeing’s Node 2 and the Hab module. Funding for life support systems that were originally planned for the Hab module continued and have been outfitted into Tranquility.

In recent months, ESA and the ISA gained NASA’s permission to convert an Italian-made space shuttle logistics module (about the size of the Columbus lab module) into a permanent ISS module. This will be added to ISS on the next shuttle flight. Together with the extra interior space of the new module and the roomier Harmony and Tranquility modules (compared with the Boeing node modules), any volume lost by the cancellation of US node and habitation modules has been regained.

And, finally, it appears that the ISS will, after all, end up with the original total of 4 node modules. The fourth node module is being built as we speak today over in Russia (to be installed at the Russian side of the space station) and may launch in the 2013-2015 time-frame. This new module will allow for expansion on the Russian side and possible Chinese participation. Yes, Russia is entertaining the idea of Chinese participation – and China has said publicly that they want in!


Very, very interresting! Thank you very much PJay_A for that excellent article!


The most interesting piece of information to me is that the ISS is NOT done growing. I knew about the 2012 launch. We will see about the next launch you mention, and about China participation. The other note is these modules do NOT require launch on the Space Shuttle.

I am wondering how long this all will be flying around in space. Also, I read that Russia is already planning to take back its portion, and continue flying it, once the US stops funding the ISS. I wonder if that will ever happen?


What about the possible addition of a bigelow module? It would likely be a small genesis sized component but it is definitely a possibility. That was a great summary though. How long are the solar arrays supposed to last? Is there a way to replace them or add on in case the station grows more? ... flatables/
Not open for further replies.

Latest posts