Titanium fire caused Dragon spacecraft explosion - SpaceX
A leak of nitrogen tetroxide, used as a liquid oxydiser, caused an explosion within a titanium check valve, investigation finds.
Tuesday 16 July 2019 09:43, UK
SpaceX and NASA believe a titanium fire was the reason a launchpad test of its Crew Dragon vehicle - intended to one day fly astronauts to the International Space Station - ended in flames.
SpaceX acknowledged the incident after images apparently showing the spacecraft bursting into flames appeared on social media, although neither organisation immediately commented.
It was a terrifying moment for the engineers involved in designing the capsule, which is meant to safely carry human passengers in space.
During a conference call, SpaceX head of mission assurance Hans Koenigsmann and NASA's commercial crew manager Kathy Lueders said their investigation suggested the explosion was due to the Dragon's pressurisation system.
The titanium component in a check valve failed due to a leak of the liquid oxydiser - nitrogen tetroxide (NTO) - and this caused an ignition within the check valve and then the subsequent explosion.
SpaceX stated: "It is worth noting that the reaction between titanium and NTO at high pressure was not expected.
"Titanium has been used safely over many decades and on many spacecraft from all around the world.
"Even so, the static fire test and anomaly provided a wealth of data. Lessons learned from the test - and others in our comprehensive test campaign - will lead to further improvements in the safety and reliability of SpaceX's flight vehicles."
Both Mr Koenigsmann and Ms Lueders refused to answer questions about when SpaceX would continue testing, and what impact the explosion would have on the Crew Dragon launch to the International Space Station.