Early in September, NASA implemented new software controls on the Hubble Space Telescope, allowing it to shut down one of the three remaining gyroscopes, reserving the third gyroscope for later use. By doing this, scientists hope to extend the Hubble's mission through mid-2008.
Gyroscopes are rotating mechanisms that remain fixated on a point in space. In space, scientists and Hubble operators need to maintain three dimensions -- up / down, left / right, and in / out. Thus, mission rules require the use of three units pointing at different locations to know where the telescope "is", and which direction it is facing. Also note that your typical picture in space requires anywhere from several minutes to several hours to properly expose, and the system needs gyroscope data to precisely look at the object being photographed.
NASA Engineers found a way to use other instrumentation aboard the Hubble to replace the data that the third gyroscope would otherwise provide.
In order to return to full functionality, however, NASA needs to send a space shuttle to the Hubble, and replace the gyros with new units to extend the lifetime of the Hubble. NASA would also replace batteries, upgrade science instruments, and repair a heat shield on the telescope. The former NASA Administrator a year or so ruled out future shuttle missions to the Hubble, but a public outcry forced NASA to re-visit this decision. NASA's current policy is to consider a Hubble mission after 2 successful return-to-flight missions. NASA also considered robotic missions to the telescope, but determined the work too complex for remote-control and installation.
Personally, I love astronomy. The pictures from Hubble are breathtakingly beautiful -- from the galaxy pictures, to some planets and moons, to colorful nebulae. Hubble was moved to record the impacts of Comet Shoemaker-Levy into Jupiter back in the late 1990's. I cannot imagine astronomy without the capabilities of this multi-million dollar telescope.