The SYS program funds fundamental research on engineered systems that will support the creation of a mathematically sound framework for systems engineering. The System Science program invites proposals that address fundamental systems issues including system performance prediction, uncertainty quantification in the systems context, theoretical foundations for aggregation in systems, decision-making in the systems context, and operation and maintenance in the systems context. Due: SYS will begin to accept proposals with the fall (September 1 - October 1) CMMI unsolicited proposal submission window. Future submissions will be accepted during both windows for unsolicited proposals. (September 1 - October 1 and January 15 - February 15). Beginning in FY2013, CAREER proposals will be accepted in these programmatic areas as well.