Hydrothermal vents were first discovered in 1977 using the human occupied submersible Alvin. After 40 years of scientific research that led to the discovery of new life forms and helped confirm the theory of plate tectonics, the National Science Foundation is providing funding to replace Alvin with a new, deeper-diving vehicle. The replacement vehicle will be capable of reaching more than 99 percent of the seafloor to depths of 6.5km (4 miles), 40% deeper than Alvin, which currently dives to 4.5km (2.8 miles).