How the SpaceX rocket failure is likely more simple, and not nearly as catastrophic, as you’d think.
So a SpaceX booster burned to the ground on the launch pad at the Cape Canaveral launch facility that the company leases from the U.S. Air Force. Space X calls this event an “anomaly” and it certainly is.
A close look at the video, presented by USLaunchReport, shows that a failure happened in the second stage and during fueling of the Falcon 9 launcher. The payload, an Israeli communication satellite that Facebook founder Mark Zuckerberg had hoped to use for Internet service delivery in sub-Saharan Africa, was destroyed.
Speculation about the cause is rampant in the mass media and most of it is flat out wrong.
This failure did not happen during a flight readiness firing and the engines were not running. The failure occurred in the second stage, whose engines are obviously not test fired while part of the stack prelaunch. Everyone is speculating, so I will too.
My best guess is second stage liquid oxygen tank failure due to a valve failure or contamination of the LOX tank, valves or piping. Anyone who has worked with pure 02 knows that the stuff is extremely dangerous. Any hydrocarbon contamination can result in a serious fire, from simple grease or oil in a valve, to the incorrect choice of seal and gasketing materials.
When that oxygen is liquefied, the problems multiply.
Lox tanks are typically pre-chilled with dry nitrogen gas before propellant loading and tanks undergo serious thermal stress, if not loaded slowly and carefully. Liquid oxygen also boils off continually during and after propellant loading and the gaseous 02 has to be vented properly to avoid dangerous pressure buildup. Even ice buildup caused by freezing condensation in the humid Florida air is a factor.
There are lots of potential causes, from simple tank structural failure to a problem with the liquid oxygen feed system in the service tower.
Cryogenic propellant/oxidizer combinations can be replaced by room temperature storable hypergolic alternatives, like the Martin Titan 2, a reliable launcher used for human spaceflight in the 1960s. But for heavy payloads, cryo is still the way to go. The Space X failure is bad, but not catastrophic or unprecedented.