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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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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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Tesla makes two big interior changes to several Model Y vehicles

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Credit: Tesla

Tesla has made two big interior changes to several Model Y vehicles in its lineup, and the changes come just as the new model year begins production.

Last year, Tesla launched the Model Y Standard, which separated the previous models into the “Premium” category. The Standard vehicles lack several features, including more premium interior materials, acoustic-lined glass, and storage.

@teslarati There are some BIG differences between the Tesla Model Y Standard and Tesla Model Y Premium #tesla #teslamodely ♬ Sia – Xeptemper

The Model Y “Premium” trims are now getting several new upgrades, which come after the company launched a seven-seat configuration of the vehicle last night in the North American market for an upcharge of $2,500.

The new Model Y seven-seat configuration did not come with just an additional row of seating; it also came with a slew of other goodies that now come standard and were previously only available on the Model Y Performance, which was launched late last year.

All Black Headliner

The new Tesla Model Y Premium trims will now come standard with a black headliner, something that many owners have been requesting for some time.

The previous grey headliner and trim within the vehicle is now gone; it will be all black on all of the Premium trims from here on out, a welcome change:

Credit: Tesla

Larger and Higher Resolution Center Touchscreen

The center touchscreen in the new Model Y Premium configuration is now larger and has a higher resolution than the previous version.

In last year’s Model Y configurations (apart from the Performance), the center touchscreen was 15.4″. Now, Tesla has decided to go with the 16″ version across all Premium trims, which is a nice step up. It was nice to see this in the Performance, but it is really great to see Tesla include this in the Model Y’s more Premium trim levels.

Tesla Model Y Seven Seater

Tesla launched the latest iteration of the seven-seater for the Model Y on Monday night. Traditionally, the Model Y seats five passengers in total, but there were calls for a more spacious version several years ago.

Tesla released it, but it was extremely tight in the back, basically reserving those back seats for only small people or children.

Credit: Tesla

The new configuration looks to be slightly more spacious in the third row, but not as much space as most would require or want. Instead,

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Lufthansa Group to equip Starlink on its 850-aircraft fleet

Under the collaboration, Lufthansa Group will install Starlink technology on both its existing fleet and all newly delivered aircraft, as noted by the group in a press release.

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Credit: Lufthansa

Lufthansa Group has announced a partnership with Starlink that will bring high-speed internet connectivity to every aircraft across all its carriers. 

This means that aircraft across the group’s brands, from Lufthansa, SWISS, and Austrian Airlines to Brussels Airlines, would be able to enjoy high-speed internet access using the industry-leading satellite internet solution.

Starlink in-flight internet

Under the collaboration, Lufthansa Group will install Starlink technology on both its existing fleet and all newly delivered aircraft, as noted by the group in a press release

Starlink’s low-Earth orbit satellites are expected to provide significantly higher bandwidth and lower latency than traditional in-flight Wi-Fi, which should enable streaming, online work, and other data-intensive applications for passengers during flights.

Starlink-powered internet is expected to be available on the first commercial flights as early as the second half of 2026. The rollout will continue through the decade, with the entire Lufthansa Group fleet scheduled to be fully equipped with Starlink by 2029. Once complete, no other European airline group will operate more Starlink-connected aircraft.

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Free high-speed access

As part of the initiative, Lufthansa Group will offer the new high-speed internet free of charge to all status customers and Travel ID users, regardless of cabin class. Chief Commercial Officer Dieter Vranckx shared his expectations for the program.

“In our anniversary year, in which we are celebrating Lufthansa’s 100th birthday, we have decided to introduce a new high-speed internet solution from Starlink for all our airlines. The Lufthansa Group is taking the next step and setting an essential milestone for the premium travel experience of our customers. 

“Connectivity on board plays an important role today, and with Starlink, we are not only investing in the best product on the market, but also in the satisfaction of our passengers,” Vranckx said. 

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Tesla locks in Elon Musk’s top problem solver as it enters its most ambitious era

The generous equity award was disclosed by the electric vehicle maker in a recent regulatory filing.

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Credit: Duke University

Tesla has granted Senior Vice President of Automotive Tom Zhu more than 520,000 stock options, tying a significant portion of his compensation to the company’s long-term performance. 

The generous equity award was disclosed by the electric vehicle maker in a recent regulatory filing.

Tesla secures top talent

According to a Form 4 filing with the U.S. Securities and Exchange Commission, Tom Zhu received 520,021 stock options with an exercise price of $435.80 per share. Since the award will not fully vest until March 5, 2031, Zhu must remain at Tesla for more than five years to realize the award’s full benefit.

Considering that Tesla shares are currently trading at around the $445 to $450 per share level, Zhu will really only see gains in his equity award if Tesla’s stock price sees a notable rise over the years, as noted in a Sina Finance report.

Still, even at today’s prices, Zhu’s stock award is already worth over $230 million. If Tesla reaches the market cap targets set forth in Elon Musk’s 2025 CEO Performance Award, Zhu would become a billionaire from this equity award alone.

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Tesla’s problem solver

Zhu joined Tesla in April 2014 and initially led the company’s Supercharger rollout in China. Later that year, he assumed the leadership of Tesla’s China business, where he played a central role in Tesla’s localization efforts, including expanding retail and service networks, and later, overseeing the development of Gigafactory Shanghai.

Zhu’s efforts helped transform China into one of Tesla’s most important markets and production hubs. In 2023, Tesla promoted Zhu to Senior Vice President of Automotive, placing him among the company’s core global executives and expanding his influence beyond China. He has since garnered a reputation as the company’s problem solver, being tapped by Elon Musk to help ramp Giga Texas’s vehicle production. 

With this in mind, Tesla’s recent filing seems to suggest that the company is locking in its top talent as it enters its newest, most ambitious era to date. As could be seen in the targets of Elon Musk’s 2025 pay package, Tesla is now aiming to be the world’s largest company by market cap, and it is aiming to achieve production levels that are unheard of. Zhu’s talents would definitely be of use in this stage of the company’s growth.

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