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среда, 24 апреля 2019 г.

Major Incident for SpaceX: Crew Dragon Capsule Exploded in Ground Test


SpaceX  — Crew Dragon / NASA Demo-1 patch.


April 23, 2019


On April 20, 2019, during a static test, the Crew Dragon capsule that had flown to the ISS was likely completely destroyed. It was to be reused for an emergency ejection test in mid-June. The next flight of a Dragon ship, which was to be flown by two astronauts, will be delayed.



Image above: Explosion of the Dragon capsule during a ground test on April 20, 2019. Image Credit: Florida Today.


SpaceX and NASA probably suffered another major setback on April 20, 2019. Indeed, the Crew Dragon capsule that returned to Earth on March 8 after a successful mission to the International Space Station (ISS) was destroyed in an explosion. In any case, this is what a video broadcast on social networks suggests (anonymously, perhaps by an employee of SpaceX) and photos taken miles away from the Kennedy Space Center showing a large cloud of orange smoke rise from the test area.


As pressure-fed rocket engines specifically designed to be the basis of a launch escape system, Crew Dragon and its SuperDraco thrusters are meant to be ready to ignite at a millisecond’s notice once they are armed in a flight-ready configuration. It’s safe to say that ten seconds away from a specifically planned ignition is one of those moments, although there is a limited chance that SpaceX’s static fire procedures intentionally diverge from an abort-triggered ignition. Regardless, the fact that Crew Dragon was destroyed before the ignition of its SuperDracos is not an encouraging sign.



Artist’s view of SpaceX Crew Dragon docking at ISS. Image Credit: NASA

Instead of a problem with its high-performance abort thrusters, it can be tentatively concluded that Crew Dragon’s explosion originated in its fuel tanks or propellant plumbing. Such an immediate and energetic explosion points more towards a total failure of propellant lines or valves (or their avionics), while another – and potentially far more concerning – cause could be one of Crew Dragon’s pressure vessels. In a space as enclosed as a Dragon capsule, the rupture of a pressure vessel could trigger a chain reaction of pressure vessel failures, freeing both oxidizer (NTO) and fuel (MMH). Known as hypergolic propellant, NTO and MMH ignite immediately (and violently so) when mixed.


It’s quite possible that the accident investigation to follow will be SpaceX’s most difficult and trying yet. Regardless of the specific cause, the footage of Crew Dragon C201’s demise does not support any positive conclusions about the fate of astronauts or passengers, had they been aboard during the violent explosion. Seemingly triggered in some way by the very system meant to safely extricate Crew Dragon and its astronauts from a failing Falcon 9 rocket, major work will need to be done to prove to NASA that the spacecraft is safe. Sadly, Boeing’s Starliner spacecraft – funded in parallel with Crew Dragon under NASA’s Commercial Crew Program – suffered a far less severe but no less significant failure during a static fire test of its own abort thrusters. Boeing was forced to remove the impacted hardware from its flight plans to extensively clean, repair, and rework the service module.



SuperDraco — Test Fire. Video Credit: SpaceX

NASA is now faced with the fact that both of the spacecraft it supported with CCP have exhibited major failures related to their launch escape systems. Crew Dragon’s catastrophic explosion comes as a particularly extreme surprise given how extensively SpaceX has already tested the SuperDraco engines and plumbing, as well as the successful completion of the spacecraft’s launch debut. In the process of DM-1 launch preparations, Crew Dragon likely spent a minimum of 80 minutes with its SuperDraco thrusters and propellant systems primed and ready to abort at any second, apparently without a single mildly-concerning issue.


Godspeed to SpaceX and NASA as they enter into this challenging and unplanned failure investigation.


Related articles:


NASA, SpaceX Launch First Flight Test of Space System Designed for Crew
https://orbiterchspacenews.blogspot.com/2019/03/nasa-spacex-launch-first-flight-test-of.html


SpaceX Crew Dragon Undock from ISS and Splashes Down in Atlantic Ocean
https://orbiterchspacenews.blogspot.com/2019/03/spacex-crew-dragon-undock-from-iss-and.html


Related links:


SpaceX Crew Dragon: https://blogs.nasa.gov/commercialcrew


Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html


SpaceX: https://www.spacex.com/


Images (mentioned), Video (mentioned), Text, Credits: Florida Today/Orbiter.ch Aerospace/Roland Berga.


Greetings, Orbiter.chArchive link


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