Change in Experiment Will Delay Shuttle's End, NY Times
"A $1.5 billion seven-ton cosmic-ray experiment scheduled to be carried aloft July 29 on the space shuttle Endeavour won't be ready until August, according to the experiment's leader, Samuel Ting of the Massachusetts Institute of Technology, delaying the end of the 29-year-old shuttle program. NASA officials acknowledged that there would be a delay but said they had not yet decided when the final launching would be. The experiment, known as the Alpha Magnetic Spectrometer, was to be installed on the International Space Station as one last scientific errand before the final shuttle launching, of the Discovery, now scheduled for Sept. 16."


I don't think that this is truely a surprise. Delays with AMS and, consequently, postponement of STS-134 have been reported on the 'Net for a while. However, this does give an excuse for manifest stretch into 2011 and possibly, extra missions as the 'end by 2010' rule is no longer
applicable. This is a good thing for the future of the ISS.