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SpaceX scrubs Starhopper’s final Raptor-powered flight as Elon Musk talks “finicky” igniters

SpaceX scrubbed Starhopper's second flight test on August 26th. Another attempt will follow on the 27th. (SpaceX)

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For unknown reasons, SpaceX’s Starhopper prototype suffered a hold just 0.8 seconds prior to its second planned flight test, a hold that was eventually followed by a decision to scrub the August 26th attempt and try again tomorrow, August 27th.

Starhopper is a full-scale, partial-height testbed for SpaceX’s next-generation Starship launch vehicle, serving more as a semi-mobile test stand for steel rockets and Raptor engines than an actual Starship prototype. The unusual vehicle took flight for the first time ever on July 25th, reaching an altitude of roughly 20m (65 ft) under the power of a single Raptor engine, capable of producing up to 200 tons (450,000 lbf) of thrust. That test also suffered a minor scrub on the 24th, followed by a successful flight one day later, a chapter that Starhopper may now mirror on its second attempted flight, a 150m (500 ft) hop.

Notably, SpaceX CEO Elon Musk took to Twitter just seconds after the rocket’s scheduled liftoff suffered a last-second hold to indicate that Raptor’s torch igniters were proving somewhat finicky relative to the chemical alternative used by SpaceX’s proven Merlin engines.

The CEO later confirmed that that comment was directly related to the 26th’s scrub, indicating that Raptor serial number 06 (SN06) needed to have its igniters inspected prior to a second hop test attempt, now scheduled to occur no earlier than 6pm EDT (22:00 UTC) on August 27th. The gist of the difficulties with Raptor’s igniter starts with the reason that SpaceX is attempting to integrate an entirely new form of ignition into the engine, replacing the methods successfully used over tens or even hundreds of thousands of seconds of firing with the company’s Merlin 1 and Merlin Vacuum engines.

Merlin 1D and MVacD both rely on a relatively simple, reliable, cheap, and easy method of chemical ignition, using a duo of pyrophoric materials known as triethylaluminum-triethylborane (TEA-TEB). When mixed, these materials immediately combust, generating an iconic green flash visible during Falcon 9 and Heavy launches, and thus producing the ‘spark’ needed to start Merlin engines.

Falcon 9 and Heavy use chemical means – TEA-TEB – to ignite all of their main and upper stage Merlin engines. (SpaceX)

Generally speaking, TEA-TEB is an excellent method of igniting rockets, even if it is more of a brute-force, inelegant solution than alternatives. It does, however, bring limitations: every single ignition requires a new ‘cartridge’ be expended, fundamentally limiting the number of times Merlin 1D (and Merlin Vacuum) engines can be ignited before and after liftoff.

This doesn’t even consider the fact that TEA-TEB are extremely complex chemical products that would be next to impossible to produce off of Earth, at least for the indefinite future.

To combat these downsides, SpaceX has designed Raptor with an entirely different method of ignition, known as torch ignition. Technically speaking, Raptor’s power, design, and methalox propellant combine to demand more than a relatively common solution, in which spark plugs are used to ignite an engine. Instead, Raptor uses those spark plugs to ignite its ignition sources, what CEO Elon Musk has described as full-up blow torches. Once ignited, those blow torches – likely miniature rocket engines using the same methane and oxygen fuel as Raptor – then ignite the engine’s methane and oxygen preburners before finally igniting those mixed, high-pressure gases in the combustion chamber.

In simple terms, the fact that Raptor is a full-flow staged-combustion (FFSC) engine means that the pressures it must operate under are extreme, verging on unprecedented in large-scale rocketry. Extremely high-pressure gases (on the order of 3,000-10,000+ psi or 200-700+ bar) are just as difficult to reliably ignite, especially if hypergolic solutions (i.e. TEA-TEB) are off the table.

To get an even ignition – critical to avoid burn-through, minor explosions, and even catastrophic engine failures – Raptor’s torch ignition may actually involve a 360-degree ring of spark plug-lit torches around the point of ignition, an undeniably complex solution.

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The first finalized Raptor engine (SN01) completed a successful static fire debut on the evening of February 3rd. (SpaceX)

However, as Musk notes, these significant, “finicky” challenges brought on by Raptor’s exotic ignition method are motivated by the potential benefits such a solution might bring. Relative to Merlin 1D’s TEA-TEB ignition, torch ignition – once optimized and matured into a reliable solution – will permit an almost unlimited number of Raptor ignitions before, during, and after flight.

Avoiding TEA-TEB and other complex chemical igniters also means that Starship will technically be able to launch to Mars or the Moon, perform injection and landing burns, maybe even hop around the surface, and still be able to return to Earth – all without resupply. Such a return voyage would still be predicated on the ability to generate the methane and oxygen propellant needed to fuel Starships, but – assuming that challenge can be solved – torch-lit Raptors would be ready for such a mission. In the event that, say, something like August 26th’s scrub happens to a Starship on Mars, the crew would also be able to get out, inspect Starship’s Raptors, and even replace faulty spark plugs if necessary.

For Starship to remain readily reusable in either of these situations, Raptor’s use of torch ignition will be absolutely critical. (SpaceX)

Technically, one could bring lots of spare TEA-TEB cartridges and install those in space or after landing, but those cartridges are quite literally firebombs waiting to ignite, whereas spare spark plugs are entirely inert.

For now, we’ll have to wait for SpaceX technicians to get their eyes and hands-on Starhopper’s lone Raptor engine to verify that its ignition hardware is in good health. If all goes well, Starhopper will attempt its final flight test as early as August 27th.

Update (August 27th): Starhopper is reportedly set for a second attempted 150m (500 ft) flight test today, scheduled to occur no earlier than 5pm EDT (21:00 UTC) on August 27th. Stay tuned for SpaceX’s official Livestream!

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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 new partnership with Uber as Semi takes center stage

Tesla and Uber will work together, using the company’s all-electric Semi, to make sustainable Class 8 electric trucks more affordable with three main strategies: Subsidized Pricing, Predictable Growth, and Optimization of Utilization.

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Credit: Uber

The Tesla Semi has led to a new partnership between the company and Uber, as the two are launching a program that aims to revolutionize logistics by making sustainable commercial vehicles more accessible.

Uber announced on Tuesday that it was planning to launch the Dedicated EV Fleet Accelerator Program in a new partnership with Tesla. Uber’s Freight division is mainly responsible for the new program, which it calls a “first-of-its-kind buyer’s program designed to make electric freight more affordable and accessible by addressing key adoption barriers.”

Tesla and Uber will work together, using the company’s all-electric Semi, to make sustainable Class 8 electric trucks more affordable with three main strategies: Subsidized Pricing, Predictable Growth, and Optimization of Utilization.

  • Subsidized Price: Fleets purchasing Tesla Semis through this program will receive a subsidy on the purchase price.   
  • Predictable Growth: Fleets will integrate their Tesla Semis into Uber Freight’s dedicated solutions for shippers for a pre-determined period. This creates an opportunity for carriers to forecast revenue with confidence, while shippers gain consistent access to reliable, zero-emission capacity. 
  • Optimize Utilization: Uber Freight taps into its extensive freight network to match carriers with consistent, high-quality freight from our strong shipper base—helping ensure the addition of these Tesla Semis stay fully utilized and carriers see dedicated, real, measurable returns from the start

Tesla will work directly with interested companies to iron out technical details about the Semi, as well as its cost of ownership based on the tailored needs of their business. Fleets can expect savings on the first day, Uber says, as they will avoid diesel fuel costs and reduced maintenance, a widely known advantage of EVs.

Uber announced that it had partnered with select carriers to pilot the Dedicated EV Fleet Accelerator Program prior to its launch:

“During the 2-month pilot program, the Tesla Semis showcased both reliability and efficiency for Uber Freight’s shipper network. Over 394 hours of drive time, carriers covered 12,377 miles. With an average net energy consumption of just 1.72 kWh per mile and only 60 hours of total charge time, these results highlight the operational viability of Tesla Semis on demanding freight lanes. “

In its press release launching the program, Uber effectively highlights how the use of the Semi can impact a company’s margins and profitability through fuel savings, reduced maintenance costs, and lower total cost of ownership.

This is something that turns so many people away from gas cars and toward EVs, so it’s no surprise that Uber wanted to emphasize this point on a larger scale with a company that utilizes a fleet of vehicles.

Tesla Semi shows strong results in ArcBest’s real-world freight trial

Tesla has been experimenting with a select group of companies, as well. It partnered with PepsiCo. several years ago, in an effort to launch a pilot program for the Semi. It had excellent results, showing higher efficiency, lower costs, and an exceptional ability to handle long runs.

Drivers have had a lot of positive things to say:

Tesla Semi earns strong reviews from veteran truckers

The Semi will enter mass production next year, but we anticipate that some companies will commit to Uber’s new platform well before then.

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Energy

Tesla recalls Powerwall 2 units in Australia

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(Credit: nathanwoodgc /Instagram)

Tesla will recall Powerwall 2 units in Australia after a handful of property owners reported fires that caused “minor property damage.” The fires were attributed to cells used by Tesla in the Powerwall 2.

Tesla Powerwall is a battery storage unit that retains energy from solar panels and is used by homeowners and businesses to maintain power in the event of an outage. It also helps alleviate the need to rely on the grid, which can help stabilize power locally.

Powerwall owners can also enroll in the Virtual Power Plant (VPP) program, which allows them to sell energy back to the grid, helping to reduce energy bills. Tesla revealed last year that over 100,000 Powerwalls were participating in the program.

Tesla announces 100k Powerwalls are participating in Virtual Power Plants

The Australia Competition and Consumer Commission said in a filing that it received several reports from owners of fires that led to minor damage. The Australian government agency did not disclose the number of units impacted by the recall.

The issue is related to the cells, which Tesla sources from a third-party company.

Anyone whose Powerwall 2 unit is impacted by the recall will be notified through the Tesla app, the company said.

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Cybertruck

Tesla launches Cybertruck orders in a new market with a catch

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Credit: Tesla

Tesla is launching Cybertruck orders in a new market, but there’s a bit of a catch.

The Cybertruck was launched in the Middle East earlier this year, as Tesla launched the ability to place a reservation for the all-electric pickup in the United Arab Emirates. It would be the first market outside of North America that would have the ability to place an order for the Cybertruck.

Tesla confirms Cybertruck will make its way out of North America this year

Other markets where the vehicle has been widely requested, like Europe and Asia, have still not approved the vehicle to be sold to the public, mostly because of size and design restrictions.

However, in the UAE, Tesla is opening up the ability for those who placed reservations for the vehicle to finally put in their order. The Order Configurator is only available to those who have already placed a reservation; it is not yet available to the public.

Tesla said it would open up the public online configurator across the Middle East in the coming weeks:

The UAE is not the only country that will have access to the Cybertruck, as fans in other Middle Eastern countries will also be able to place orders soon. Tesla announced back in April that Saudi Arabia and Qatar would also have Cybertruck deliveries.

These vehicles will be built at Tesla’s Gigafactory Texas plant just outside of Austin, as Gigafactory Berlin and Gigafactory Shanghai, two factories located in the same hemisphere as the Middle East, do not have established lines for Cybertruck production.

As for the other markets, Tesla CEO Elon Musk has hinted that the company could develop a smaller Cybertruck for those markets, as he admitted that in the long term, it likely made sense to build a more compact version for regions where roads are traditionally tighter.

Elon Musk hints at smaller Tesla Cybertruck version down the road

There has been no evidence of Tesla developing this more compact version, but it could eventually happen.

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