The quarter-scale model was tested for the best possible towing configuration in Carderock’s tow tanks, which are normally used to test ships, submarines and unmanned vehicles. Then they were taken to the outdoor wave pond at the U.S. Army’s Aberdeen Proving Grounds in Maryland, where the engineers tested it in Sea States 3 (a sea wave with a significant wave height of about three feet) through 6 (a wave height of at least 16 feet). “On average,” says Carrico, “those waves are taller than the capsule. It was pretty dramatic. It would be lost as it would go down into the troughs of the waves, and then reappear back on the crest.” The results allow NASA to predict the behavior of the capsule—and gauge how rough seas will affect returning astronauts.
“We got a first-hand look at what it takes to tow the capsule,” said Richard Banko, the lead engineer and construction manager at Carderock. “If the weather is bad enough, and the recovery ship isn’t close by, any ship of opportunity can tow the capsule into sheltered waters.”