Although Mir earns currency from the US, Europe and Japan, its costs are a problem for the cash-strapped agency. Getting rid of the extra overhead of the docking software licence would have been ideal. But the unmanned Progress cargo craft hit and punctured one of Mir's living modules. Luckily, the hole was only the size of a postage stamp: had it been larger, decompression would probably have killed the trio, who were not in spacesuits.
A new book, Dragonfly: Nasa and the crisis aboard Mir, says the astronauts' lives may have been saved by an accidental collision within the spacecraft just before the crash, between British-born Michael Foale, of Nasa, and Commander Tsibliyev.
Dr Foale accidentally hit the Russian's arm, then controlling the cargo ship's movements, with his foot.
Aleksandr Lazutkin, the other Russian on board, said: "As soon as Michael hit Vasily's hand the [cargo] ship moved and hit Mir with its side. If it had continued the way it was flying, it might have been much worse. It would have hit with the sharp edge of the rear, rather than the blunt edge of the side."
However, the trio's accounts differ: Dr Foale suggests the impact had no effect because it was too brief, while Commander Tsibliyev suggested it was one of the "little things" contributing to the crash. In addition, Commander Tsibliyev was exhausted from a 12-night"sleep-study" experiment that had ended 24 hours earlier, in which equipment he had worn made it almost impossible to sleep. Despite asking to be taken off the experiment five days early, he was overruled by ground controllers.
And he had no data about the range or speed of the approaching ship except for what he could work out using a stopwatch and handheld range-finder. But that proved useless, because the Progress was obscured by Mir's solar panels.
The background to the drama, which happened on 25 June last year as Mir was orbiting 250 miles (400km) above the Earth, emerges in the new book, by Bryan Burrough, an American journalist, to be published in January. He spoke to the astronauts and to Russian and US ground controllers.
Mr Burrough discloses that Nasa officials were not told about the risks involved in the test. "We knew very little of the technical detail," Jim Van Laak, second in command of Nasa's Mir programme, said. "[Before the test] we didn't know much and they told us even less. I guess now that sounds pretty stupid." Mir had a perfectly suitable computerised docking system, able to bring the cargo ship to a safe docking distance from Mir. But the Ukrainian programmers' announced intention to raise the licence fee would have put the already shaky Russian Space Agency budget far into the red. So ground controllers decided to institute a manual docking system, called Toru, to be controlled from Mir. It had a computer link to two joysticks and had been used many times for docking from 50 yards or so. But the Russian test tried to use Toru to dock Progress from five miles away, resulting in the near-fatal collision.
Russia's space budget has been under increasing pressure since the collapse of the Soviet regime. Although Mir earns foreign revenue, it is increasingly decrepit. The Russians plan to dispose of it next year by lowering its orbit until it begins to burn up and crashes into the Pacific.Reuse content