Several weeks ago, SpaceX suffered another blow to its efforts to make private spaceflight a viable business when a Falcon 9 rocket exploded on the launchpad during a pre-flight test. The explosion resulted in the loss of the rocket and the payload, a satellite that was to be used for Facebook’s internet.org project. The firm began an investigation immediately, and has now provided an update on the cause. The explosion was reportedly a result of a breached helium containment system.
This might sound familiar, because it was also a problem with the helium storage tanks that caused the 2015 in-flight explosion that destroyed a resupply payload bound for the International Space Station. SpaceX is careful to point out that the recent anomaly had nothing to do with the 2015 explosion. In that incident, a strut that held the helium containers in place failed long before it had reached the rated tolerance levels. That caused the helium tank to rupture and lead to the breakup of the rocket.
In the September 2nd incident (which Elon musk says was not an explosion, but just a very fast fire), the helium storage system was breached in the second stage oxygen tank. Helium is used in rocket engines to maintain proper pressurization inside the tank as fuel is depleted. Because it’s stored as a supercooled liquid, a breach can lead to serious damage to the rocket.
While SpaceX knows what caused the explosion, it doesn’t yet know why. SpaceX is working with the FAA, NASA, the US Air Force, and outside industry experts to determine how the helium tank was damaged, but there’s precious little data from the vent itself. The Falcon 9 reports more than 3,000 different channels of engineering data to mission control, but from the first signs of an anomaly to complete loss of data was just 93 milliseconds. The investigation team has scoured the landscape near Launch Complex 40 to find all the debris from the rocket. It has all been cataloged, photographed, and stored in a hangar for further analysis.
Video of the anomaly (seen above) is quite dramatic, but as per regulations, no one was nearby during the fueling operation. There was substantial damage to the launchpad systems, but all the SpaceX support facilities nearby managed to get away with only minor damage. The company is still planning to launch again in November and is still building rocket components at its California facility for cargo missions and the upcoming NASA Commercial Crew Program flights. If the September 2nd incident is found to have been caused by the Falcon 9 design, SpaceX will be able to make changes to the rocket before getting back to the launchpad.