Space Exploration Technologies Corp. (SpaceX), which plans to begin executing next year on a $1.6 billion NASA contract to deliver cargo to the international space station, did itself no favors by taking so long to publicly acknowledge that an engine anomaly occurred during a Dec. 8 demonstration flight of its Falcon 9 rocket. The commercial spaceflight startup says the incident was blown out of proportion, and that looks to be the case, but the company’s months-long silence is at least partly to blame for that.

To be clear, the flight, the first of three planned under NASA’s Commercial Orbital Transportation Services (COTS) demonstration program, is widely viewed as a success. The Falcon 9 lofted SpaceX’s Dragon cargo capsule, which made two orbits before re-entering the atmosphere, splashing down at the designated location and being recovered intact. The company has since proposed combining the second and third COTS demo objectives into a single mission, and while NASA has not yet given its official approval, indications are the agency will do so in the coming weeks.

It wasn’t long after the flight, however, that rumors began swirling that all didn’t go as well as advertised. Things came to a head in June when SpaceX sued an aerospace consultant who had emailed Bryan O’Connor, then NASA’s top flight safety official, to check out what he said were reports that Falcon 9 experienced a double engine failure and that the entire first stage blew up shortly after separation. In his email, Joe Fragola, a vice president at the consulting firm Valador and a recognized spaceflight safety expert, also said he had heard that SpaceX was withholding this information from NASA pending company verification, according to the lawsuit.

SpaceX, which hopes to develop a crew-carrying Dragon variant, said in its complaint that no failure or explosion occurred and that NASA was kept fully informed about the vehicle’s in-flight performance. The lawsuit claimed that Mr. Fragola’s inquiry helped fuel a perception within the U.S. government, the company’s most important customer, that something had gone dangerously wrong on the flight. The matter was settled out of court in August.

NASA now confirms that it was informed of the anomaly shortly after the flight. But SpaceX didn’t level with the broader public until Sept. 9, when Ken Bowersox, the company’s vice president for astronaut safety and mission assurance, said in an interview that two of the Falcon 9’s nine first-stage engines experienced an “oxidizer-rich shutdown.” This came only after a Sept. 9 public meeting of a pair of NASA’s outside advisory committees during which another Valador safety expert, Charles Daniel, said SpaceX officials acknowledged the incident in an August meeting at NASA’s Johnson Space Center.

Mr. Daniel characterized the event as a premature engine shutdown; Mr. Bowersox, a former NASA astronaut, denied the shutdown was premature. There also seems to be some dispute over the seriousness of the event. But clearly something unexpected occurred.

SpaceX Chief Executive Elon Musk has since said avoiding a future engine shutdown of this sort is simply a matter of putting more fuel in the Falcon 9’s tank. It would have been even easier to nip the rumors of a narrowly averted disaster in the bud. All SpaceX had to do was publicly disclose what had happened reasonably soon after the fact. NASA withheld that information, referring all media questions about the rocket’s performance to SpaceX. The company’s extended silence left the impression that the incident was far more serious than it actually was.

Holding its tongue might have been a defensive reaction on SpaceX’s part and that would be understandable: The company has always had detractors, initially because of its audacity and, more recently, for emerging as a competitive threat to some in the space industry establishment.

But the company’s handling of the engine shutdown incident only played into the hands of its critics. U.S. taxpayers have invested considerable sums of money in SpaceX, and NASA already has entrusted it with a key role in maintaining the $100 billion space station. Greater transparency would be one indication that SpaceX is up to the job.