November 25, 2008 Vol. 1, Issue 11
It is a vehicle designed to travel to a cold, dark place where humans have never been before. Sound familiar?
The place is the deep ocean, and the vehicle is the next-generation Alvin, a human-rated deep-sea exploration vehicle. The engineers at the Woods Hole Oceanographic Institute (WHOI) are working to design and build a vehicle that will surpass the current Alvin’s maximum depth of 4,500 meters (2.8 miles) and enable it to take humans to 6,500 meters (more than 4 miles). This would allow scientists to see 99% of the ocean floor.
Some of the technical challenges Alvin presents are similar to those encountered by NASA designers: adding battery capacity without adding weight, expanding the crew area within the vehicle, and improving ergonomics and electronics. Others are more specific to the deep-sea environment.
The key to reaching new depths is building a vehicle that can withstand greater pressure, which will reach nearly 5 tons per square inch at a depth of 6,500 meters. The primary construction material for the pressurized cabin (the “personnel sphere”) is titanium. A new sphere that can withstand this pressure will have 3-inch thick walls and weigh roughly 11,000 pounds.
Some of the project management challenges, such as cost spikes in materials, are also common to spaceflight projects. The price of titanium has undergone a fivefold increase since the National Science Foundation (NSF) first awarded WHOI $21.6 million in 2004 to build the next-generation Alvin.
Researchers from WHOI and NSF are scheduled to conduct a Phase I preliminary design and cost review in June 2009.
