Friday, February 5, 1999 Published at 13:13 GMT
Znamya - what went wrong?
Znamya: A Russian failure
By BBC News Online Science Editor Dr David Whitehouse
According to the Russian scientist who has been called the architect of the Znamya project, Vladimir Syromiatnikov, the space mirror failed because of incompetence.
At first all went well, the undocking of the Progress supply craft from the Mir space station went perfectly. It moved to about 100 metres away from Mir and stopped.
Looking out the windows of Mir, the cosmonauts could see the Progress hanging in space some way off. The folded-up space mirror was in eight drums attached to the circumference of the Progress. To unfurl the mirror, the craft had to be spun on its axis.
So the thrusters were commanded to fire. But just as the Progress spacecraft was being spun to begin the deployment of the foil mirror an extra, unwanted command was sent to the craft telling it to deploy an antenna usually used for communication during docking manoeuvres.
Disaster - the antenna extended and immediately became entangled in the foil. For a while controllers at mission control just outside Moscow were blissfully unaware as the partially deployed space mirror started to crumple.
Then they looked with horror at the television pictures being beamed back from Mir.
Quickly commands were sent to the troublesome antenna to retract, but already several metres of foil had become wrapped around it.
To the dismay of the engineers, TV pictures showed that the foil had been torn in several places.
About an hour later, a second attempt to spin the mirror free was tried but with no success.
It was soon recognised that Znamya could never be unfurled and that any further attempts could risk losing control of the Progress spacecraft, which had to be destroyed in the Earth's atmosphere the following day.
Journalists were told a third attempt might be made late Thursday/early Friday to unfurl the mirror, but, in truth, mission control knew Znamya was lost.
This failure can be put down to human error - something that the Mir space station has experienced quite a bit of in the past few years.