SpaceX, founded by Elon Musk, seen above in 2014, is investigating what caused an engine to explode Sunday during a test fire.
(Robyn Beck/AFP/Getty Images)

This post has been updated.

SpaceX is investigating why one of its rocket engines exploded during a test earlier this week at the company’s facility in Texas, the company confirmed Wednesday.

The explosion involved the next generation of the company's Merlin engine. The mishap occurred Sunday during what the company called a “qualification test.” No one was injured, but now the company founded by tech entrepreneur Elon Musk once again has to figure out what went wrong with its hardware.

In 2015, SpaceX’s Falcon 9 rocket exploded a couple of minutes after lifting off from Cape Canaveral en route to deliver cargo to the International Space Station. No one was on board and no was injured.

Then, in September 2016, another Falcon 9 blew up, this time while on the launchpad as it was being fueled ahead of an engine test fire. Again, no one was hurt.

The company said Wednesday in response to questions that it is “now conducting a thorough and fully transparent investigation of the root cause” of the explosion. “SpaceX is committed to our current manifest, and we do not expect this to have any impact on our launch cadence.”

Later on Wednesday, a SpaceX spokesman said the engine that exploded was a new engine that hasn't yet flown. Testing on that engine will be suspended while the company looks into what went wrong. Preparations for the engines currently in operation would continue in a few days, once their testing stand is repaired.

The setback comes as SpaceX is having a record-setting year. The company has launched 16 times successfully this year, doubling the number of its launches in a single year and tying the most number of launches by its chief rival, the United Launch Alliance, according to SpaceNews.

In addition to flying commercial satellites, it launches cargo to the International Space Station for NASA and is expected to start delivering astronauts there by as early as next year. It is also deploying highly sensitive satellites for the Pentagon. Officials from the Air Force's Space and Missile Systems Center were at SpaceX's test site during the explosion, an Air Force spokeswoman said.

SpaceX is scheduled to launch its Falcon 9 rocket, which is powered by nine of the Merlin engines on its first stage, at least three more times this year. Its next launch, a national security mission, is scheduled for next week from the Kennedy Space Center.

Musk has said the company also plans to launch its Falcon Heavy rocket for the first time this year. But he has warned that the Heavy is a complex rocket, which uses 27 first-stage engines, and that it too could explode.

“I hope it makes it far enough away from the pad that it does not cause pad damage. I would consider even that a win, to be honest,” he said earlier this year. “Major pucker factor, really.”