According to a 6 October 2003 NASA press release, "ICESat was launched January 12, 2003, on a Boeing Delta II rocket from Vandenberg Air Force Base, Calif. On March 29, ICESat's Laser 1 unexpectedly stopped working after providing 36 days of data. NASA will issue a report shortly on the reason for the anomaly."
NASA Watch has learned that the probable cause of ICESat's Laser 1 failure was discovered in July 2003. This was done by examining an engineering copy of the laser. Within the laser, components made of gold and indium come in contact with one another. During the operation of the laser, these two elements have reacted together and caused failure of some of some components. This propensity for gold and indium to react is fairly well-documented. Sources suggest that this design flaw should have been uncovered during an initial design review.
ICESat's Laser 2 (turned on well ahead of schedule) is running more or less nominal at present. However, all three of ICESat's lasers have the gold/indium design. It is not known how long the second, and then the third laser will last. The baseline 3 year mission plan called for each laser to be turned on, in succession, as the previous laser reached the end of its design life. One laser has already failed.