This month, a slow-swimming robot known as Spray will attempt to glide roughly 2,484 nautical miles across the Atlantic, from the southern tip of Greenland to the coast of Spain. An autonomous underwater vehicle, or AUV, Spray is a joint venture between the Woods Hole Oceanographic Institution in Massachusetts and the Scripps Institution of Oceanography in California. When deployed, it will act as an aquatic sentinel, gathering data on temperature, currents and salinity that will help scientists better understand the role of oceans in regulating the global climate.