According to Spaceflight Now, some nearby workers said they heard an explosion, though no injuries have been reported.
Photos taken from a beach near the Florida test site showed plumes of smoke rising from Cape Canaveral.
It has had to rely instead on Russian Federation and its Soyuz spacecraft.
Now less clear, those options are growing more important.
The incident is certain to delay efforts to have U.S. astronauts back flying United States...
Speculation suggests that the explosion during testing could push SpaceX's manned launch back to next year, but that is unconfirmed at this time. Following the successful maiden unmanned flight in March, the company was hoping to test the capsule with pilots on board in July. Florida Today claims it received unconfirmed reports that 'indicated the capsule was destroyed.' It's unclear at this time what kind of delay this event may introduce to SpaceX's work under NASA's Commercial Crew Program.
A SpaceX Crew Dragon spacecraft suffered what the company said was an "anomaly" during static fire tests of its abort engines April 20, dealing a setback to the company's plans to fly a crewed test flight later this year.
Crew Dragon was scheduled to conduct a key test of its emergency abort system in June.
SuperDraco Rocket Engine SuperDraco is a hypergolic propellant liquid rocket engine designed and built by SpaceX. "The initial tests completed successfully but the final test resulted in an anomaly on the test stand". "We will learn, make the necessary adjustments and safely move forward with the Commercial Crew Program", NASA Adminstrator Jim Bridenstine said in a statement on Twitter.
The company has been working to redesign pressurized helium tanks at the root of that rocket mishap, and also in the Dragon's propulsion system, though there's no indication that system was at fault Saturday.
SpaceX and Boeing are both building capsules to carry astronauts to and from the International Space Station under commercial contracts with NASA that are aimed at ending the agency's sole reliance on Russian Soyuz spacecraft to ferry US and partner astronauts to low-Earth orbit. Another important test of the Starliner's abort system, called a pad abort, is targeted for this summer in New Mexico.