According to SpaceX, the explosion of a rocket and spacecraft was probably as a result of a flawed strut. However, United Launch Alliance said its tank design is principally different compared to that of SpaceX's. As per ULA's President and CEO Tory Bruno, the tank design of ULA rockets is not that complex.

SpaceX CEO Elon Musk said on Monday that a strut that broke probably caused the explosion of the Falcon 9 rocket and Dragon spacecraft that disintegrated 139 seconds into its journey to the space station.

As per reports, Dragon was carrying over 4,000 pounds of supplies and payloads. It was also containing the first of two international docking adapters to facilitate future commercial crew spacecraft, together with the SpaceX Crew Dragon, to dock to the space station.

SpaceX said in an investigation update on Monday that preliminary analysis indicates that the overpressure in the upper stage liquid oxygen tank was led by a flawed piece of support hardware within the second stage.

SpaceX said that "the helium system integrity was breached" together with the failure of the strut. According to SpaceX, "This caused a high pressure event inside the second stage within less than one second and the stage was no longer able to maintain its structural integrity".

According to Bruno, tank design of ULA "is less complex and does not have interior helium tanks for pressurization". The part, where problem occurred on Falcon, is not there on Atlas or Delta, Bruno said, mentioning ULA rockets.