I might be able to shed some light on this.
I was familiar with the original plan for the Stansted terminal, it’s originally planned 4 satellites and the transit system, having had a detailed briefing and tour of the site in the final stages of construction and fitting out.
As part of that visit, I travelled on the transit system before it saw live passenger use.
I also passed through there a couple of times, as a passenger, in the first year of operation.
The original plan was for 4 identical satellites, all served by the transit system, running on a horse shoe shaped route.
Sat 1 & 2 were built at the same time as the terminal building, along with the transit system, with a plan to build Sat 3 & 4 and extend the transit system to serve them, in later years when traffic levels increased.
During construction, it was realised that there would be a need to provide separate facilities for domestic passengers. Surprisingly, something that had been thought unnecessary in the design phase.
Bear in mind that this was before the Low Cost revolution had barely started and the likes of EasyJet did not yet exist.
Stansted was intended to be almost exclusively served by package tour flights, to take pressure of Gatwick, which at the time was experiencing a large expansion of international scheduled flights.
There was no expectation of requiring facilities for domestic or CTA flights.
Subsequently the link bridge from the main terminal building to Sat 2 was installed at a late stage, either just before opening, or shortly afterwards.
This link bridge was not part of the original design.
The terminal opened with the original Sat 1 & 2.
Development and expansion since those early days have taken a different path to that of the original concept and design.
You will note that Sat 3, added many years later, is of a different, budget design and not as a replica of the first two satellites.
The terminal building was designed to allow expansion, by removing the curtain walling at either end and adding extra bays to lengthen the same structural design by up to double the original size.
Although this design facility was utilised to expand the terminal in the late “noughties”, construction of the Radisson Blu Hotel slap bang on the land original earmarked for terminal expansion, has effectively capped any further extension.
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