NASA engineers said Oct. 30 they were not sure what caused two parachutes to fail following the test flight of the experimental Ares 1-X rocket, resulting in damage to the vehicle’s spent booster when it splashed into the Atlantic Ocean harder than planned.

“There was an indication we had a parachute problem,” said Bob Ess, NASA’s Ares 1-X mission manager. “Afterward, when we saw the parachutes we assumed, properly, that [the rocket] must have hit harder than it should have.”

While engineers are poring through data returned from test to learn what happened, Ess said they are not too worried.

“Damage to the booster is not really a concern to us,” he said. “We don’t plan on reusing it. We got the data and a good test of the parachutes.”

Ares 1-X, a suborbital prototype of the Ares 1 rocket NASA has been developing since 2005 to carry astronauts into orbit, lifted off Oct. 28 from Kennedy Space Center, Fla. During two minutes of powered flight, the 100-meter-tall rocket reached an altitude of 45 kilometers before its first stage — a four-segment solid rocket booster — separated from a dummy upper stage that tumbled into the ocean and sank as planned. But two of the three parachutes designed to gently lower the rocket’s first stage into the ocean malfunctioned, resulting in a harder-than-expected splashdown. Divers sent to recover the first stage took photos showing a giant dent near the base of the booster.