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Talkin' Turtles with NASA Environmental Engineers
11.08.12
 
As one could imagine, there are many variables involved in successfully completing NASA’s mission. One factor that sometimes isn’t immediately thought of when thinking of those variables is environmental impacts.

Recently, environmental engineers at NASA’s Wallops Flight Facility partnered with the Lower Shore Family YMCA in Pocomoke, Md., to study a potentially critical environmental effect of NASA’s hurricane research program.

Environmental Engineers Joel Mitchell and Shari Silbert work with Lower Shore YMCA Director Dan Prescott to research dropsondes.For NASA’s Hurricane and Severe Storm Sentinel (HS3) mission unmanned aerial vehicles called Global Hawks flew to altitudes of approximately 60,000 feet to study the dynamics of hurricanes and tropical systems. At those altitudes, the Global Hawks drop small sensor packages called dropsondes. These dropsondes consist of a 12-inch long tube attached by a tether line to a small pyramidal parachute. After the dropsondes are released from the Global Hawk, the dropsonde measures wind speed, humidity, air temperature and atmospheric pressure as the unit descends towards the ocean surface. The data collected from these unique instruments is transmitted back to waiting meteorologists. The data is continuously sent back to the ground until the transmitter is shorted out by the sea water. The mission ends here, right? Wrong.

What happens to the dropsondes after they short out? Are they safe for marine species, particularly sea turtles? Could sea turtles become entangled in the tether? Would the parachute be mistaken for a jellyfish and eaten by turtle, as jellyfish are a diet staple of some marine turtles? These questions were posed by NOAA’s National Marine Fisheries Service, and they were important questions.

In walks the Wallops Environmental Office. Environmental engineers at Wallops decided to conduct a series of sink rate tests to determine how quickly these dropsondes would sink. When looking for a place to conduct these tests, the Lower Shore Family YMCA seemed like the most logical choice, as the pool was deep enough to do the tests in a safe, controlled area.

The team did countless studies to verify their results. The results found that the dropsondes sank at a rate of over one foot per second. Within an hour, the instruments were at a depth of approximately 4,000 feet or on the bottom of the ocean. This leaves very little time for the dropsonde to become entangled or to become a meal for turtles or marine species.

Through this research, NOAA’s National Marine Fisheries Services determined that the dropsondes in support of the Hurricane and Severe Storm Sentinel Mission posed no threat to protected marine species. This was a great report for the entire HS3 team, as safety of all things is paramount at NASA.