An emergency servicing mission may be flown to the Hubble Space Telescope in October because the telescope's gyro system could be on the brink of total failure.

The third of its six gyros has now failed and NASA is considering whether to replace them earlier than the third servicing mission, planned for June 2000. The gyros are a vital part of the telescope's fine-pointing system.

The US space agency's options are to hold out until June 2000, to move the June mission to earlier in 2000, or to split the mission into two, flying the first part in October and mounting the second flight about a year later.

Delays to the International Space Station flight schedule mean that it would be possible for an October flight to be flown, but interrupting the 13-flight Space Shuttle schedule for 2000 may present difficulties.

Source: Flight International