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SpaceX says Crew Dragon capsule exploded due to exotic titanium fire

Crew Dragon tests its SuperDraco-powered launch abort system in 2015. (SpaceX)

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6 years ago

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SpaceX has announced via an official update and conference call the preliminary results of a failure investigation convened immediately after Crew Dragon capsule C201 exploded in the midst of an April 20th static fire test.

Hosted by SpaceX Vice President of Mission Assurance Hans Koenigsmann and NASA Commercial Crew Program manager Kathy Lueders, the call provided some minor additional insight beyond a fairly extensive press release issued just prior. According to the preliminary results from SpaceX’s failure investigation, Crew Dragon’s explosion was unrelated to the spacecraft’s propellant tanks, Draco maneuvering thrusters, or SuperDraco abort engines. Rather, the cause lies in a more exotic and unanticipated chemical/material interaction between a plumbing valve, liquid oxidizer, and a helium-based pressurization system.

When metal burns

According to Hans Koenigsmann, SpaceX is approximately 80% of the way through what is known as the fault tree, essentially meaning that the failure investigation is 80% complete. That additional 20% could certainly throw some curveballs but the SpaceX executive was fairly confident that the results presented on July 15th would be representative of the final conclusion.

The ultimate (likely) cause of Crew Dragon’s extremely energetic and destructive explosion centers around the spacecraft’s extensive SuperDraco/Draco plumbing and its associated pressurization system, which uses helium to keep the pressure-fed engines, propellant tanks, and feed lines around 2400 psi (16.5 megapascals). Necessarily, this method of pressurization means that there is direct contact between the pressurant (helium) and the oxidizer/fuel, thus requiring some sort of valve preventing the pressurized fluid from flowing into the pressurization system.

A detailed view of some of the Draco and SuperDraco-related plumbing used on Crew Dragon – in this case, the capsule that will now fly SpaceX’s In-Flight Abort test. (Pauline Acalin, August 2018)

During flight-proven Crew Dragon capsule C201’s April 20th static fire testing, that is reportedly exactly what happened. Over the course of ground testing, a “check valve” separating the pressurization system and oxidizer leaked what SpaceX described as a “slug” of nitrogen tetroxide oxidizer (NTO) into the helium pressurization lines. Around T-100 milliseconds to a planned ignition of the vehicle’s 8 SuperDraco abort engines, the pressurization system rapidly “initialized” (i.e. quickly pressurized the oxidizer and fuel to operational pressures, ~2400 psi).

To do this, helium is rapidly pushed through a check valve – designed with low-molecular-mass helium in mind – to physically pressurize the propellant systems. Unintentionally, the NTO that leaked ‘upstream’ through that valve effectively was taken along for the ride with the high-pressure burst of helium. In essence, picture that you crash your car, only to discover that your nice, fluffy airbag has accidentally been replaced with a bag of sand, and you might be able to visualize the unintended forces Dragon’s check valve (the metaphorical airbag) was subjected to when a “slug” of dense oxidizer was rammed into it at high speed.

Crew Dragon C201 displays its heat shield after the spacecraft’s first orbital-velocity Earth reentry, March 8th. (NASA/Cory Huston)

In itself, this sort of failure mode is not hugely surprising and SpaceX may have even been aware of some sort of check valve leak(s) and accepted what it believed to be a minor risk in order to continue the test and perhaps examine Dragon’s performance under suboptimal conditions. What SpaceX says it did not realize was just how energetic the reaction between the NTO and the check valve could be. SpaceX’s understanding is that the high-speed slug of dense NTO was traveling so fast and at such a high pressure that, by impacting the titanium check valve, it quite literally broke the valve and may have chemically ignited the metal, thus introducing a slug of burning NTO into the liberated NTO system itself – effectively a match tossed into a powder keg.

It’s unclear if the ignition came from a chemical reaction between titanium (a technically flammable metal similar to magnesium) and NTO, or if the source came from the titanium valve being smashed apart, perhaps quite literally creating a spark as metal debris violently interacted. Either way, the solution – as SpaceX perceives it – is the same: instead of a mechanical check valve (simple but still not 100% passive), the barrier between pressurant and oxidizer (as well as fuel, most likely) will be replaced with something known as a burst disk. According to Koenigsmann, only a handful (~4) of those valves exist and thus need to be replaced by burst disks, a relatively fast and easy fix.

Burst disks are single-use and inherently unreusable, but they are also completely passive and simply do not leak until subjected to a specific amount of pressure. Because they are single-use, they can’t be directly tested prior to flight, limiting some of the in-principle reliability for the sake of an extremely leak-proof barrier.

A test of one of Crew Dragon’s four ‘powerpacks’, featuring two SuperDracos and three Dracos. (SpaceX)

Ultimately, both Koenigsmann and Lueders went out of their way to avoid answering any questions about SpaceX’s Crew Dragon upcoming test and launch schedule and what sort of delays the explosion will ultimately incur. Both individuals were nevertheless upbeat and by the sound of it, delays to Crew Dragon will be far less severe relative to delays caused by a pressure vessel or engine failure. For the time being, NASA has published a tentative target of mid-November 2019 for Crew Dragon’s first crewed launch to the International Space Station, while Lueders and Koenigsmann expressed hope in a 2019 launch but refused to give a specific estimate of the odds of that occurring.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Elon Musk

Elon Musk is stepping up for Tesla Service in a big way

Elon Musk has stepped up to resolve a handful of customer issues regarding vehicle service.

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16 minutes ago

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August 11, 2025

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tesla service
Credit: Tesla

Elon Musk is stepping up to help customers in a big way, especially when they are having issues with Tesla’s Service.

Perhaps one of the biggest advantages Tesla owners have is access to Musk through X, his social media platform. Over the years, we’ve seen Tesla add features, refine its cars’ performance, and more, all through asking Musk directly through a post.

Now, Musk is stepping up in another way by resolving a few Service complaints that customers had.

The first occurred last week when a recall on a Tesla battery was not honored by Service. The company sought $30,000 for a replacement and labor, which was not right. Musk responded that he would personally investigate the matter. The vehicle was fixed at no cost as it was a recall, and was ready for pickup the next day.

It also revealed a new strategy Tesla is using to combat service communication issues:

Tesla creates clever solution to simplify and improve its Service

The next occurred with a Cybertruck owner who was in Japan. Their car was parked at an airport in the U.S. and had lost a vast majority of its state of charge, leaving them just fifty miles of range at the time.

Musk reached out to the owner and said Service will take care of the car and will investigate the cause of the battery drain:

There are not too many companies out there where the CEO will get involved with individual issues like these. It’s pretty exclusive to Tesla, as Musk has commonly stepped up to resolve complaints with vehicles or to confront features that some owners might find useful.

Service has been a weak point of the company for some time, but it has worked to refine and resolve customer complaints by building more Service Centers across the world that can handle these issues.

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Elon Musk

Tesla CEO Elon Musk confirms Robotaxi is opening to the public: here’s when

Anyone will be able to request a Tesla Robotaxi in September, Elon Musk said this morning.

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2 hours ago

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August 11, 2025

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Credit: Joe Tegtmeyer | X

Tesla CEO Elon Musk has confirmed that the company’s Robotaxi platform is opening to the public, and he even gave a timeline for when anyone will be able to access one for a ride.

Tesla’s Robotaxi platform launched to a small group on June 22 in Austin, Texas. The company has continued to expand the number of riders and its geofence over the past month and a half.

Tesla officially launches Robotaxi service with no driver

Additionally, it launched rides in the Bay Area of California, but it differs slightly, as the Texas Robotaxi platform does not utilize a Safety Monitor in the driver’s seat. In California, the monitor sits in the driver’s seat.

As the geofence, service areas, and testing populations expand, Tesla fans are awaiting their elusive emails that enable their ability to use the Robotaxi platform. It now seems that the email will come soon, as Musk said Tesla will open up public access to Robotaxi next month:

Tesla has been prioritizing safety over anything else with the launch of the Robotaxi platform, which is why it has been slow to push invitations to new riders. It is confident in the abilities of the platform and its Full Self-Driving suite, which has been proven with data.

However, even a single accident could set Tesla back years in terms of its development of self-driving cars. It is not a risk it is willing to take.

Musk said during the recent Q2 Earnings Call:

“We need to make sure it works when the vehicles are fully under our control. It’s kind of one step at a time here. We don’t want to jump the gun. As I said, we’re being paranoid about safety. But I guess next year is I’d say confidently next year. I’m not sure when next year, but confidently next year, people would be able to add or subtract their car to the Tesla, Inc. fleet.”

As the platform will expand in Austin and the Bay Area for anyone, Tesla still continues to reiterate that Robotaxi will be available for everyone sometime next year, as Musk said in the quote above.

Things will continue to improve over time, and Tesla will likely expand its geofence in both regions in the coming weeks. It has already done that in Austin twice, with about a doubling in size occurring both times.

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Elon Musk

Tesla warns consumers of huge, time-sensitive change coming soon

Tesla is urging customers to take delivery of their new EV by September 30 in order to take advantage of the $7,500 tax credit.

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3 hours ago

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August 11, 2025

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(Credit: Tesla)

Tesla is continuing to warn consumers of a huge, time-sensitive change that is coming soon, as the end of the EV tax credit is less than two months away.

The EV tax credit has offered $7,500 off new EVs and $4,000 off used EVs for certain individuals who qualify due to income. For years, it has been a great incentive for consumers, and it has improved further as car companies were able to apply the credit at the point of sale starting in 2023.

Tesla is ready with a perfect counter to the end of US EV tax credits

However, with the Trump Administration, it always seemed as if the EV tax credit was in jeopardy. Earlier this year, the White House officially announced that it would do away with it completely.

On September 30, the tax credit will be abolished. In order to utilize it, customers will have to take delivery of their vehicle by that date. Orders placed before September 30 without delivery by that day will not be able to utilize the credit.

Tesla is truly pushing this point incredibly hard: the sooner an order gets in, the more likely you are to take delivery of the car by September 30.

The end of the EV tax credit is something that has been looming on the minds of electric carmakers, consumers, and investors.

The $7,500 discount for buying a clean energy vehicle truly puts many of the cars in a much more affordable price range. Without it, the least expensive Tesla model will be the Model 3 Rear-Wheel-Drive, which starts at $42,490.

That price comes down to $34,990 with the tax credit, and brings the monthly payment down about $130, depending on how much money is put down.

Despite the change, CEO Elon Musk does not believe it will impact Tesla negatively. In fact, he has been in favor of getting rid of the EV tax credit for several years, believing it will actually work to Tesla’s advantage.

Perhaps the most interesting thing that will come of this is how all EV makers will be impacted by the loss of credit. Musk believes Tesla will come out as the big winner here, especially as it plans to roll out new affordable models sometime this year.

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