Photo: SpaceX
On April 20, 2019, a few weeks after its successful first flight to the International Space Station (ISS), the SpaceX Crew Dragon spacecraft was obliterated in an explosion that occurred during an in-flight abort test. Several months after the incident, the space company published the results of the investigation.
As per SpaceX, the explosion was caused by a leak of liquid oxidizer, the nitrogen tetroxide (NTO). The fuel somehow managed to find its way into the high-pressure helium tubes “at high speed during rapid initialization of the launch escape system” and destroyed a titanium check valve.
The check valve then ignited and ended in the explosion that destroyed the spacecraft.
The reason for the leak itself seems to be the explosive reaction between titanium and NTO at high pressure, a thing SpaceX says it was unaware of, as this material “has been used safely over many decades and on many spacecraft from all around the world.”
Armed with this new knowledge “will lead to further improvements in the safety and reliability of SpaceX’s flight vehicles.”
To fix the problem in the rest of the Crew Dragons, SpaceX says it has already begun taking additional steps, including the elimination of any flow path that could allow liquid propellant to enter the gaseous pressurization system and the replacement of the check valves with burst disks.
The explosion of the Crew Dragon caused some changes in the flight program of the company. Another Crew Dragon, originally assigned to the second demonstration mission to the ISS will now be used to perform the first in-flight abort test, and the one assigned to carry humans for the first time in space has been designated to perform the second uncrewed flight.
You can have a look at SpaceX’s findings about the April explosion, complete with a technical analysis, in the document attached below.
The check valve then ignited and ended in the explosion that destroyed the spacecraft.
The reason for the leak itself seems to be the explosive reaction between titanium and NTO at high pressure, a thing SpaceX says it was unaware of, as this material “has been used safely over many decades and on many spacecraft from all around the world.”
Armed with this new knowledge “will lead to further improvements in the safety and reliability of SpaceX’s flight vehicles.”
To fix the problem in the rest of the Crew Dragons, SpaceX says it has already begun taking additional steps, including the elimination of any flow path that could allow liquid propellant to enter the gaseous pressurization system and the replacement of the check valves with burst disks.
The explosion of the Crew Dragon caused some changes in the flight program of the company. Another Crew Dragon, originally assigned to the second demonstration mission to the ISS will now be used to perform the first in-flight abort test, and the one assigned to carry humans for the first time in space has been designated to perform the second uncrewed flight.
You can have a look at SpaceX’s findings about the April explosion, complete with a technical analysis, in the document attached below.
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