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SpaceX preps Texas Starship’s second tank dome for installation in latest milestone

On August 4th, SpaceX technicians flipped the second of three tank domes destined for installation inside the Texas orbital Starship prototype. (Elon Musk)

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During an August 4th visit to SpaceX’s Boca Chica Starship build site, CEO Elon Musk captured and shared photos showing technicians carefully flipping the second of three propellant tank domes destined for installation inside the company’s South Texas orbital Starship prototype.

This is the latest visible step towards the completion of one of SpaceX’s two “Mk 1” Starships, said by Elon Musk to be the first orbit-capable prototypes. Per recent tweets, either or both of the prototypes – being built concurrently at separate sites in Florida and Texas – could be ready for their first flight tests as early as September or October 2019.

Set to be powered by up to three sea-level (SL) Raptors and three vacuum-optimized Raptors (RVacs), Musk has stated that SpaceX’s first two orbital Starship prototypes will likely begin flight testing with just the three SL engines installed. Recently, the SpaceX CEO did, however, indicate that development of Raptor’s vacuum variant – postponed as of a September 2018 update – had been reprioritized and said that it could actually be ready sooner than later.

Raptor Vacuum will have a significantly larger nozzle compared to the sea level engine it will be based on. According to Musk, RaptorVac will have a nozzle diameter of roughly 2.8m (9.2 ft), while the SL Raptor features a ~1.3m (4.2 ft)-diameter nozzle. With a larger diameter nozzle, a chemical rocket engine can technically generate more thrust and is significantly more efficient due to an increased expansion ratio, meaning the difference in the diameter of the nozzle exit and combustion chamber throat.

In the very simplest sense, this efficiency and thrust increase comes from the fact that a longer nozzle allows the exiting gas (reaction mass) to reach a higher velocity, thus conveying more momentum onto the rocket it is propelling.

BFS (circa 2017) shows off its complement of SL and Vacuum Raptor engines. SpaceX is moving back to something similar to this. (SpaceX)
Technically speaking, this Raptor is the smaller (sea-level) version of the engine. (SpaceX)

Starship’s Raptor engines, of course, use liquid methane as fuel and liquid oxygen as their oxidizer. According to SpaceX, fully fueling a combined Super Heavy and Starship stack will require an incredible ~5000 tons (11 million pounds) of propellant – ~1500 tons for Starship and ~3500 tons for Super Heavy.

To contain such a huge amount of fuel and oxidizer, Starship (and Super Heavy) must effectively be turned into extremely mass-efficient pressure vessels, capable of supporting something like 20 kilograms of propellant with every kilogram of rocket structure.

Technicians carefully guide the Texas Starship’s first bulkhead into its propellant and propulsion section on July 30th. (NASASpaceflight – bocachicagal)

SpaceX’s installation of bulkheads in the Texas Starship prototype are thus an inherent indication that the rocket is being readied to play the role of a massive, ultra-strong pressure vessel. While sitting vertically, a fueled Starship’s tank domes will be subjected to immense pressures and forces from the sheer weight of the liquid oxygen and methane held above them.

Additionally, the rearmost dome will likely be partially or fully integrated into Starship’s thrust structure, meaning that it will simultaneously be subjected to the thrust of 3-6 Raptors (as much as 600-1200 tons of thrust) and the gravity of 300 metric tons of methane. It’s unclear if SpaceX is planning to reinforce Starship and Super Heavy tank bulkheads with structural add-ons, but it’s safe to assume that some level of reinforcement will be required.

A look inside the 2017 version of SpaceX’s 9m-diameter Starship. (SpaceX)
Per the above diagram and the fact that SpaceX flipped bulkhead #2 upside down, the dome pictured above is almost certainly the aforementioned “common dome” that will separate Starship’s methane and oxygen tanks. (NASASpaceflight – bocachicagal)

SpaceX CEO Elon Musk’s planned August 24th presentation on Starship and Super Heavy will likely (hopefully) provide some new details on the structure and general design of the company’s advanced, next-generation rocket.

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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 lands approval for Robotaxi operation in third U.S. state

On Tuesday, Tesla officially received regulatory approval from the State of Arizona, making it the third state for the company to receive approval in.

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Tesla has officially landed approval to operate its Robotaxi ride-hailing service in its third U.S. state, as it has landed a regulatory green light from the State of Arizona’s Department of Transportation.

Tesla has been working to expand to new U.S. states after launching in Texas and California earlier this year. Recently, it said it was hoping to land in Nevada, Arizona, and Florida, expanding to five new cities in those three states.

On Tuesday, Tesla officially received regulatory approval from the State of Arizona, making it the third state for the company to receive approval in:

Tesla has also been working on approvals in Nevada and Florida, and it has also had Robotaxi test mules spotted in Pennsylvania.

The interesting thing about the Arizona approval is the fact that Tesla has not received an approval for any specific city; it appears that it can operate statewide. However, early on, Tesla will likely confine its operation to just one or two cities to keep things safe and controlled.

Over the past few months, Robotaxi mules have been spotted in portions of Phoenix and surrounding cities, such as Scottsdale, as the company has been attempting to cross off all the regulatory Ts that it is confronted with as it attempts to expand the ride-hailing service.

It appears the company will be operating it similarly to how it does in Texas, which differs from its California program. In Austin, there is no Safety Monitor in the driver’s seat, unless the route requires freeway travel. In California, there is always a Safety Monitor in the driver’s seat. However, this is unconfirmed.

Earlier today, Tesla enabled its Robotaxi app to be utilized for ride-hailing for anyone using the iOS platform.

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Tesla ride-hailing Safety Monitor dozes off during Bay Area ride

We won’t try to blame the camera person for the incident, because it clearly is not their fault. But it seems somewhat interesting that they did not try to wake the driver up and potentially contact Tesla immediately to alert them of the situation.

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Credit: u/ohmichael on Reddit

A Tesla Robotaxi Safety Monitor appeared to doze off during a ride in the California Bay Area, almost ironically proving the need for autonomous vehicles.

The instance was captured on camera and posted to Reddit in the r/sanfrancisco subreddit by u/ohmichael. They wrote that they have used Tesla’s ride-hailing service in the Bay Area in the past and had pleasant experiences.

However, this one was slightly different. They wrote:

“I took a Tesla Robotaxi in SF just over a week ago. I have used the service a few times before and it has always been great. I actually felt safer than in a regular rideshare.

This time was different. The safety driver literally fell asleep at least three times during the ride. Each time the car’s pay attention safety alert went off and the beeping is what woke him back up.

I reported it through the app to the Robotaxi support team and told them I had videos, but I never got a response.

I held off on posting anything because I wanted to give Tesla a chance to respond privately. It has been more than a week now and this feels like a serious issue for other riders too.

Has anyone else seen this happen?”

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My Tesla Robotaxi “safety” driver fell asleep
byu/ohmichael insanfrancisco

The driver eventually woke up after prompts from the vehicle, but it is pretty alarming to see someone like this while they’re ultimately responsible for what happens with the ride.

We won’t try to blame the camera person for the incident, because it clearly is not their fault. But it seems somewhat interesting that they did not try to wake the driver up and potentially contact Tesla immediately to alert them of the situation.

They should have probably left the vehicle immediately.

Tesla’s ride-hailing service in the Bay Area differs from the one that is currently active in Austin, Texas, due to local regulations. In Austin, there is no Safety Monitor in the driver’s seat unless the route requires the highway.

Tesla plans to remove the Safety Monitors in Austin by the end of the year.

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Tesla opens Robotaxi access to everyone — but there’s one catch

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Credit: Tesla

Tesla has officially opened Robotaxi access to everyone and everyone, but there is one catch: you have to have an iPhone.

Tesla’s Robotaxi service in Austin and its ride-hailing service in the Bay Area were both officially launched to the public today, giving anyone using the iOS platform the ability to simply download the app and utilize it for a ride in either of those locations.

It has been in operation for several months: it launched in Austin in late June and in the Bay Area about a month later. In Austin, there is nobody in the driver’s seat unless the route takes you on the freeway.

In the Bay Area, there is someone in the driver’s seat at all times.

The platform was initially launched to those who were specifically invited to Austin to try it out.

Tesla confirms Robotaxi is heading to five new cities in the U.S.

Slowly, Tesla launched the platform to more people, hoping to expand the number of rides and get more valuable data on its performance in both regions to help local regulatory agencies relax some of the constraints that were placed on it.

Additionally, Tesla had its own in-house restrictions, like the presence of Safety Monitors in the vehicles. However, CEO Elon Musk has maintained that these monitors were present for safety reasons specifically, but revealed the plan was to remove them by the end of the year.

Now, Tesla is opening up Robotaxi to anyone who wants to try it, as many people reported today that they were able to access the app and immediately fetch a ride if they were in the area.

We also confirmed it ourselves, as it was shown that we could grab a ride in the Bay Area if we wanted to:

The launch of a more public Robotaxi network that allows anyone to access it seems to be a serious move of confidence by Tesla, as it is no longer confining the service to influencers who are handpicked by the company.

In the coming weeks, we expect Tesla to then rid these vehicles of the Safety Monitors as Musk predicted. If it can come through on that by the end of the year, the six-month period where Tesla went from launching Robotaxi to enabling driverless rides is incredibly impressive.

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