seafloor. Samples and data collected during IODP drilling expeditions are available to scientists and teachers on an open-access basis, once members of the expedition parties have completed their initial studies. Planning IODP drilling: science advisory structure Drilling proposal process Drilling proposals originated with science proponents, often researchers in geology, geophysics, microbiology, paleontology, or seismology. Once submitted to IODP, the proposal was carefully evaluated by the Science Advisory Structure (SAS), a group of technical review panels. Only those proposals judged as the greatest value based on scientific and technical merit were scheduled for implementation. SAS panels provided advice on drilling proposals to both proponents and IODP management. Drilling proposals were accepted twice a year, in April and October, and could be submitted to IODP electronically via their website. The science plan A ten-year program plan called the Initial Science Plan (ISP) guided IODP investigation. Specific scientific themes were emphasized in the ISP: investigation into the deep biosphere and subseafloor life; climate change; solid Earth cycles; and geodynamics As described in the ISP, IODP sought to develop better understandings of: the earthquake-generating zone beneath convergent continental margins; the complex microbial ecosystem that exists beneath the seafloor; the nature of gas hydrates that lie beneath continental margins; climate history, extreme climates; rapid climate change; the role of continental break-up in sedimentary basin formation; the formation of volcanic rifted margins and oceanic plateaus through time; and drilling to Earth's mantle to examine and monitor a complete section of oceanic crust Tools critical to these goals included a riser-equipped drilling vessel, a riserless vessel, additional platforms suited to mission specific expeditions, enhanced downhole measurement devices, and long-term monitoring instrumentation. Engineering proposals An engineering proposal submission process, initiated in April 2007, facilitated the acquisition of existing or latent technology to be used in IODP operations. Science and drilling operators Drilling operations were conducted and managed by three IODP implementing organizations: United States Implementing Organization (USIO) carried out expeditions on the riserless drilling vessel JOIDES Resolution; ECORD Science Operator (ESO) managed mission specific expeditions on various platforms; Center for Deep Earth Exploration (CDEX) managed operations aboard the riser-equipped drilling vessel Chikyū. Each drilling expedition was led by a pair of co-chief scientists, with a team of scientists supported by a staff scientist. Each implementing organization provided a combination of services: technical, operational, and financial management; logging; laboratory; core repository; data management; and publication. Although each implementing organization