For want of a pin, the use of a spaceship’s parachute was lost.

That may be a simplistic way to explain why one of the three parachutes on Boeing’s CST-100 Starliner space taxi failed to open. It does, however, serve as a cautionary tale about the one obvious glitch in Monday’s pad abort test of the Starliner, a craft that’s due to start transporting NASA astronauts to and from the International Space Station next year.

Overall, the test was judged a success: The uncrewed Starliner fired the rocket engines on its launch abort system, slowed its descent with the aid of the two parachutes that did open, and deployed its airbags to make a perfectly acceptable landing at the U.S. Army’s White Sands Missile Range in New Mexico.

If there had been crew aboard, and if an emergency involving the Starliner’s Atlas 5 rocket were to come up on the Florida launch pad, the astronauts would have made a safe escape and landing — as a splashdown in the Atlantic rather than a touchdown in the desert.

“This was a robust test of what the vehicle could do if we had an issue on the pad. A huge test,” Kathy Lueders, program manager for NASA’s Commercial Crew Program, said today during a teleconference reviewing the pad abort test.

The glitch involving the third parachute wasn’t serious enough to force a delay for the Starliner’s first uncrewed test flight to the space station and back, set for launch no earlier than Dec. 17. Nevertheless, it was important for Boeing’s engineers to determine the root cause and take steps to avoid having the anomaly happen again.

John Mulholland, vice president and program manager of Boeing’s Commercial Crew Program, said the Starliner team quickly identified the root cause: the lack of a secure connection between the main chute and the pilot chute that was supposed to pull it out of the spacecraft.

In response to a question, Mulholland said the problem came down to a pin that’s supposed to be inserted through a loop on the end of a parachute line.

“That pin wasn’t through the loop,” he said.

Close-out crews missed spotting the problem because the lines and their connections were tucked away within protective covers. But a review of photos taken during the close-out process, as well as an inspection of the hardware recovered from this week’s test, pinpointed what went wrong, Mulholland said.

He said Boeing’s team have taken “a number of fairly easy steps” to make sure the parachute linkages are secure in the future. For example, engineers will conduct “pull tests” — which sounds as if they’ll be yanking on the lines to make sure they’re properly attached.

The Starliner team is also double-checking the 18 critical linkages in the parachute lines on the Starliner craft that’s due for launch next month, Mulholland said.

He said all but three of those linkages have been verified over the past couple of days, and he expects those remaining three to be verified as well. “We have 100% confidence in the parachute,” Mulholland said.

Overall, the Starliner’s performance was “outstanding,” Mulholland said. Some observers may have wondered about a spurt of reddish nitrogen tetroxide propellant that emanated from the capsule during its descent, but Mulholland said those leftovers are released “by design.”

Engineers will pore over the data from this week’s test for the next week and a half.

If everything checks out, NASA and Boeing will move ahead with next month’s launch of the uncrewed Starliner from Cape Canaveral Air Force Station in Florida. And if that test proceeds smoothly, a demonstration mission is expected to send two NASA astronauts and a Boeing test pilot to the space station next year.

Meanwhile, SpaceX is proceeding with tests of its Crew Dragon spaceship, which is also on track to start launching astronauts to the space station next year.

An uncrewed in-flight abort test is expected to take place by the end of December. In preparation for that high-altitude test, SpaceX is planning an on-the-ground static-fire test of the Crew Dragon’s thruster system on Saturday. A similar test went awry in April, adding months of delay to SpaceX’s development schedule.