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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.

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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.

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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NASA taps SpaceX to launch the telescope that could unlock new worlds

NASA’s Roman Space Telescope heads to orbit this August aboard SpaceX’s Falcon Heavy with massive scientific ambitions.

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SpaceX is set to play a central role in one of NASA’s most anticipated science missions in years. The company’s Falcon Heavy rocket, currently the most powerful operational launch vehicle in the world, will carry the Nancy Grace Roman Space Telescope into orbit on August 30 from Kennedy Space Center in Florida. Roman is now in final preparations inside the Payload Hazardous Servicing Facility, where on June 26 technicians used a crane to lift the observatory into a specialized stand for fueling and pre-launch testing.

Roman is named after Nancy Grace Roman, NASA’s first chief of astronomy, whose career helped shape how the agency approaches space science.

NASA chose SpaceX Falcon Heavy because of Roman’s needs to reach a specific orbit far from Earth, well beyond where a standard Falcon 9 can deliver it. The Falcon Heavy, which first flew in 2018, has since become NASA’s go-to option for missions that need serious muscle without the cost and complexity of older launch systems.

Celebrating SpaceX’s Falcon Heavy Tesla Roadster launch, seven years later (Op-Ed)

Roman will carry a field of view at least 100 times wider than the Hubble Space Telescope, meaning it can photograph enormous swaths of the universe in a single shot rather than the narrow slices Hubble captures. That difference in scale is significant. While Hubble reshaped our understanding of the cosmos over 30 years, Roman is built to work faster and wider, surveying hundreds of millions of galaxies at once.

One of Roman’s most compelling capabilities is its potential to discover and photograph planets orbiting stars outside our solar system, and with enough precision to directly image planets that would otherwise be lost. That means scientists could study the atmosphere and surface characteristics of distant worlds rather than simply confirming they exist. Combined with Roman’s sweeping field of view, the telescope could detect thousands of exoplanets, and some of those planets may be in habitable zones where liquid water could exist. No telescope currently in operation has this level of power and capability. That capability alone could change what we know about other worlds, and perhaps finally answer the question: are we the only intelligent lifeforms in existence? 

What Roman actually finds once it reaches orbit is an open question, and that is exactly what makes this launch worth watching.

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Tesla confirms crucial detail of Miami Robotaxi launch

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Credit: Tesla

Tesla has confirmed a crucial detail of its Miami Robotaxi launch, stating that the fleet is operating on an Unsupervised basis, joining a few other cities where company employees do not watch over the vehicles from inside.

Tesla’s Head of AI, Ashok Elluswamy, confirmed the detail on X, answering a highly speculated question about the Robotaxi Service in Miami, which was launched on June 3:

The first launch of Robotaxi in Florida, Miami presents a unique opportunity for Tesla as it is operating the Unsupervised Robotaxi ride-hailing service in a major tourist hotspot in the Sunshine State. It also signals the suite will expand to other cities soon; many have requested Orlando, a heavy tourist spot with Disney and other resorts nearby, get access to the program soon as well.

Miami is getting a conservative rollout as well, just as Tesla has done with other cities. The initial geofence covers a compact 10–14 square mile zone in western Miami-Dade County, primarily West Miami extending toward Doral and Sweetwater. It is bounded roughly by SR-826 (Palmetto Expressway) to the north and US-41 (Tamiami Trail) to the south, excluding downtown Miami, Miami Beach, the airport, and most of Coral Gables.

Tesla has also been pretty slim on other details. For example, Tesla has not disclosed the exact fleet size, but field reports and license plate tracking indicate just two unsupervised Model Y vehicles were active on launch day, increasing to three within 48 hours.

According to The Road to Autonomy, a nearby staging lot near Miami International Airport holds dozens of Cybercabs alongside additional Model Y units, suggesting capacity for rapid scaling as demand and data collection grow.

The confirmation of Robotaxi being Unsupervised carries immense weight. It establishes that Tesla’s Miami Robotaxi operations run without human safety drivers or remote supervision, relying entirely on the company’s Full Self-Driving technology. Miami becomes the second major U.S. city after Austin to offer unsupervised Robotaxi rides from day one.

The move reflects rapid progress in Tesla’s AI efforts. Neural networks trained on vast real-world data now handle complex urban environments, including South Florida’s heavy traffic, pedestrians, and rainy conditions. Industry observers see it as validation of Tesla’s vision-centric, data-driven approach versus traditional rule-based systems; a truly unorthodox approach in this day and age.

Challenges remain, including regulatory oversight, public trust, and scaling the fleet to match geofence ambitions. Miami’s small initial footprint and limited vehicles highlight a deliberate, measured expansion strategy focused on safety and data gathering.

Nevertheless, the unsupervised confirmation marks a pivotal milestone. It showcases technical readiness and advances Tesla’s vision of transforming vehicles into autonomous revenue generators while reshaping urban mobility. For Miami users, driverless transportation has moved from concept to reality.

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Radiologist who drove Tesla off cliff has attempted murder charges dismissed

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model-y-devil-devils-slide
Credit: ABC7 News Bay Area/YouTube

A California radiologist who drove his Tesla Model Y off a 250-foot cliff in an attempt to kill his family has had his charges dismissed after doctors say he is “doing well” in a mental health program.

Dharmesh Patel was charged with three counts of attempted murder in connection with a January 2023 crash where he drove his Tesla off a cliff, injuring his wife and two children, aged 7 and 4 at the time.

Patel drove the Tesla off Devil’s Slide in California, an area that is extremely rough to the point that investigators and rescuers expected the worst when arriving at the scene for the first time. Patel supposedly had schizoaffective disorder, according to Deputy District Attorney Dominique Davis.

Shockingly, Patel’s wife, who was in the vehicle, testified that she did not want her husband to be prosecuted, noting that their children missed their father and they wanted him to come back home. Patel’s attorney argued, “not everyone who commits a crime is a criminal.”

Doctor who took Tesla off cliff gets support from unlikely person

A three-day trial in Mental Health Diversion Court ruled in Patel’s favor, which kept him out of jail and instead on house arrest. He was admitted to a Mental Health Diversion Program, which he successfully completed, the Associated Press reported. San Mateo County District Attorney Steve Wagstaffe said the judge was “required by law” to dismiss the charges:

“If the person who’s given mental health diversion follows the treatment plan, there’s nothing that can be done, and at the end of the two years he gets it wiped out of his record.”

Wagstaffe said he has argued, along with other DAs in California, to have attempted murder removed from the list of charges eligible to be dismissed due to mental health diversion programs.

Patel had the charges officially dismissed on Monday; his wife waited for him as he left court and they departed the building together, according to Mercury News. Patel surrendered his California medical license in December.

The crash has been one of the best examples of Tesla’s incredible engineering, which has saved four lives in this particular instance. The car was totalled but kept the four human beings alive and safe, which is something that many referred to as “an absolute miracle.”

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