"NASA will host a media teleconference at 6 p.m. EDT today to discuss a significant Hubble Space Telescope anomaly that occurred this weekend affecting the storage and transmittal of science data to Earth. Fixing the problem will delay next month's space shuttle Atlantis' Hubble servicing mission.
The malfunctioning system is Hubble's Control Unit/Science Data Formatter - Side A. Shortly after 8 p.m. on Saturday, Sept. 27, the telescope's spacecraft computer issued commands to safe the payload computer and science instruments when errors were detected within the Science Data Formatter. An attempt to reset the formatter and obtain a dump of the payload computer's memory was unsuccessful."