As I understand it... the objectives were, essentially in order of importance:
It was 'naively' expected that it would take 2-3 years to assemble the complex of base block, Kvant-1, and four front-end modules, and it was expected that the station would serve in this configuration for at most 3 years. Given the engineering knowledge base from Salyuts 6 and 7 this was technologically if not operationally reasonable.
Mir must be judged, primarily in this context. Of course, it took much longer than expected to add even Kvant-1 and the first pair of forward modules. In fact, Kristall was not added until 1990. At that time, the second pair of modules were put 'on hold'. Mir would have to 'make do' with what it had.
The mission had evolved.
In an era of 'pay as you go', it was supposed to make biological agents and semiconductors of commercial value. The host economy was not suited to accept such materials even if they were produced.
The mission evolved again.
As a 'pay a fee to visit' laboratory, it was a success. Indeed, it was soon oversubscribed. Even though it is soon to be deorbited, there are visitor contracts outstanding.
The crucial point to bear in mind is that Mir is (to steal a phrase) a TECHNOLOGY DEMONSTRATOR.
It was the first modular station assembled in orbit. It was the first to be inhabited on an on-going basis. It has extended the human time-in-space sufficently to equate to a trip out to Mars. It did undertake a lot of research work. It did host many visiting researchers. For many years, it has been the only game in town. It is still the only outpost in orbit. Of course, it is beyond its service life. But this is not a criticism. Even now, learning how the technology degrades, and how to repair it, and do so IN SPACE, is continuing its primary mission as a technology demonstrator. Mir is delivering ENGINEERING KNOWLEDGE, and that, to my mind, is every bit as useful as a piece of semiconductor, some influenza virus, a protein crystal, a telescopic observation, or indeed an earth picture.
Mir is not, and never has been, a scientific venture. As a technology demonstrator it is an exercise in engineering. It is now in its third five-year lifetime, and it is still habitable and facilitating useful work, so it has undoubtedly succeeded in its primary objectives.
author of "The Mir Space Station: A Precursor To Space Colonisation"
Return to Mir Space Station Observing.