quality:correction, structural:reformatting
Ageing systems and atmosphere

In the later years of the programme, particularly during the Shuttle- Mir programme, Mir suffered from various systems failures. It had been designed for five years of use, but eventually flew for fifteen, and in the 1990s was showing its age, with frequent computer crashes, loss of power, uncontrolled tumbles through space and leaking pipes. Jerry Linenger in his book about his time on the facility says that the cooling system had developed tiny leaks too small and numerous to be repaired, that permitted the constant release of coolant. He says that it was especially noticeable after he had made a spacewalk and become used to the bottled air in his spacesuit. When he returned to the station and again began breathing the air inside Mir, he was shocked by the intensity of the smell and worried about the possible negative health effects of breathing such contaminated air.

Various breakdowns of the Elektron oxygen-generating system were a concern; they led crews to become increasingly reliant on the backup Vika solid-fuel oxygen generator (SFOG) systems, which led to a fire during the handover between EO-22 and EO-23. (see also ISS ECLSS)