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SpaceX fires up Starship rocket twice in 30 hours ahead of next big tests

Starship SN4 is looking downright shiny after successfully completing multiple wet dress rehearsals and two Raptor static fire tests. (NASASpaceflight - bocachicagal)

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SpaceX has successfully fired up a full-scale Starship rocket for the second time in barely 30 hours and removed the ship’s Raptor engine to perform an additional suite of “cryo testing”.

Around 7pm CDT on May 6th, SpaceX technicians began loading the fourth full-scale Starship with liquid oxygen and methane, filling up a large portion of its massive propellant tanks. Just the latest in a line of several tests involving wet dress rehearsals (WDR) completed in the days prior, this test would soon become exceptional. About an hour and a half after work began, Starship SN4’s lone Raptor engine ignited and burned for ~3 seconds, marking the first time in history a next-generation SpaceX rocket truly came alive with one of the engines designed to take it all the way to orbit.

In line with tests performed with Starhopper – a low-fidelity, subscale tested that flew twice with Raptor – last year, it would have been business as usual if SpaceX had called it a day and moved on to something else with Starship SN4. Instead, Starship performed another WDR and fired up its Raptor engine for a second time in just 30 hours after SpaceX teams inspected the rocket and cleared it for another round. It’s unknown why two back-to-back static fires were performed but, to be clear, every step Starship SN4 takes forward is a step into uncharted territory. Already, the ship’s next steps could come as soon as Friday, May 8th.

According to CEO Elon Musk, SpaceX’s second Starship SN4 static fire test was completed successfully and actually marked the operational debut of a critical aspect of the next-generation launch vehicle and spacecraft. Known as header tanks, Starship needs two smaller secondary propellant tanks to complement its main tanks, a need driven mainly by the challenges of landing such a large and mobile spacecraft. Smaller header tanks will also make it dramatically easier for SpaceX to insulate cryogenic propellant and ensure it remains liquid over long-duration cruises in space, but safe and reliable landings are a more pressing concern for these early prototypes.

During landing operations, the main benefits smaller header tanks offer are relative ease of pressurization (needed to safely feed Raptor engines) and a much lower risk of issues from sloshing, which can introduce bubbles and voids that can obliterate rocket engines if ingested. Impressively, per Musk, Starship SN4 completed its second static fire test using its internal liquid methane header tank – a sort of bubble attached to the bottom of the main methane tank dome.

Starship SN5’s common methane and oxygen tank dome (and spherical methane header tank) is pictured here on May 1st. (NASASpaceflight – bocachicagal)
While header tanks will be invaluable for Starships attempting to landing on other planets or Moons after weeks- or months-long coasts in space, they’re also a great help for landing on Earth. (SpaceX)

Starship’s liquid oxygen header tank is situated at the tip of the conical nose section, a part that all full-scale ships have been tested without thus far. However, the use of the fuel header tank on May 7th means that Starship SN4 already has a functional, plumbed header tank installed, verifying the partial functionality of a critical part of the next-generation launch vehicle. A second static fire will have also provided SpaceX a wealth of extra data about Raptor’s performance while installed on Starship, invaluable at such an early stage of integrated testing.

Two Starship static fires now under its belt, SpaceX removed SN4’s Raptor engine around 12 hours after its second test and returned it to storage at the company’s nearby factory facilities. According to public notices provided by Cameron County, Texas officials, SpaceX’s next Starship SN4 activity is expected to occur on May 8th with backup windows on the 9th and 10th and will involve “cryo testing”.

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SpaceX removed Starship SN4’s Raptor engine after two successful back-to-back static fires. (NASASpaceflight – bocachicagal)

The most obvious conclusion is that SpaceX – having completed enough static fire testing to verify Starship SN4’s performance – now wants to really put the rocket through its paces with another cryogenic test. Completed on April 26th, the ship’s first cryogenic ‘proof’ test maxed out at around 4.9 bar (70 psi), enough for low-stress hop tests but well short of the sustained pressure needed for orbital spaceflight. While testing singular propellant tanks in the first few months of 2020, Musk revealed that SpaceX was targeting a minimum of 6 bar (~90 psi) for orbital Starship flights – ~8 bar (115 psi) with a 25% safety factor.

Pictured here on May 7th, Starship SN5 could be just days away from its final tank section stacking operation and just a week from rolling to the launch pad for proof testing. (NASASpaceflight – bocachicagal)

The company actually achieved 8.4 bar with one of its Starship test tanks, the same processes of which were used to build Starship SN4, but a full-scale ship has yet to demonstrate those pressures. Now, SpaceX already has a fifth full-scale prototype (Starship SN5) likely just a week or so away from pad readiness, meaning that Starship SN4’s potential destruction during pressure testing wouldn’t have a big impact on plans for a series of imminent flight tests. If SN4 survives pressure testing, it would likely have its Raptor engine reinstalled and move on to a 150m (500 ft) hop test.

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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Verizon, AT&T and T-Mobile are trying to shut Starlink out before FCC vote

AT&T, Verizon and T-Mobile want 290 MHz cut from an FCC satellite plan before Thursday.

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Starlink D2D direct to device vs Verizon, AT&T (Concept render by Grok)

AT&T, Verizon and T-Mobile are asking the Federal Communications Commission to pull nearly 300 MHz of spectrum out of a proposal that would let satellite companies like SpaceX offer cell service directly to ordinary phones. The request lands one day before the agency votes on it.

The FCC will vote Thursday, October 29, on a notice of proposed rulemaking that would make an additional 482 MHz available for direct to device service, expanding the number of eligible bands from five to 13, according to the FCC fact sheet. It would also scrap the rule requiring a satellite operator to lease spectrum from carriers, replacing it with a certification that the operator has coexistence agreements in place or holds the terrestrial license itself.

That second path matters for SpaceX. As Teslarati reported earlier this month, SpaceX agreed to buy Grain Management’s nationwide 800 MHz portfolio to turn Starlink Mobile into a full US carrier, adding to the spectrum it already bought from EchoStar.

The carriers want two bands removed, 2.5 GHz and 3.45 GHz, which make up 290 MHz of the 482 MHz on the table. Through industry group CTIA, they argued that about 300 million users depend on those bands and that satellite operations in them are not technically feasible. T-Mobile, which calls 2.5 GHz the foundation of its Ultra Capacity 5G network, said in its own filing that satellite interference could wipe out up to 96% of a cell site’s uplink coverage area and cut uplink speeds by 88% to 99%.

Executives from all three carriers met with FCC staff on October 20, and T-Mobile CEO Srini Gopalan met separately with FCC Chairman Brendan Carr. T-Mobile’s role stands out because it is still SpaceX’s US launch partner for Starlink Mobile. The three carriers have also teamed up on their own satellite joint venture to pool spectrum, a move widely seen as a response to Starlink.

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SpaceX is asking for the opposite. In an October 23 filing after meetings with FCC staff and commissioners’ offices, the company asked regulators to add the 902 to 928 MHz band to the proposal. “Doing so now saves time later,” SpaceX wrote. The company also asked the FCC to modernize interference rules and align satellite deployment requirements with those for terrestrial cell networks, saying the goal is to let satellite and ground networks work together so Americans stay connected wherever they are.

The carriers have not been shy about how they view SpaceX as a competitor. On Verizon’s third quarter earnings call Monday, its chief executive said Starlink Mobile “just can’t compete with a terrestrial network” and estimated SpaceX would need four to six years and $300 billion to $500 billion to build a full US carrier network.

Thursday’s vote will not settle which bands survive. Adopting the notice opens a public comment period, with final rules to come later in the proceeding. The FCC already considered and rejected 2.5 GHz for satellite coverage once, in 2024. SpaceX also is not the only satellite player watching: the FCC approved Amazon’s $11.6 billion acquisition of Globalstar on October 27, giving its planned direct to device fleet its own mobile satellite spectrum.

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Tesla Semi catches fire in California: what we know

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Credit: KTVU

A Tesla Semi caught fire in Hayward, California, which caused both directions of traffic to shut down for hours before being completely reopened early on Wednesday, the California Highway Patrol said.

The fire occurred just after 5:30 local time in Hayward on Tuesday, as the Semi caught fire in the southbound lanes of I-880 before CHP officials made the decision to shut down both lanes of traffic due to potential risks from hazardous chemical smoke.

There were no injuries reported.

The cause of the fire is currently unknown, as neither Tesla nor the CHP have not determined a cause.

However, some images taken before the Semi was completely destroyed by the fire seem to indicate this might have been an older unit, as it appears to be one of the designs that Tesla shipped as part of its pilot program, before revising it and starting mass production just a month ago.

At the time of publication, CHP had not returned our request for a comment for additional details, including the Semi involved and any potential collaboration on an investigation between the CHP and Tesla. We will update this story when we hear back from them.

The southbound lanes were reopened at 3:30 a.m. on Wednesday, with the northbound lanes opening last night a few hours after the fire began. The CHP did state that the lithium batteries were “incredibly difficult to extinguish,” according to NBC Bay Area.

The truck’s driver said that the Semi caught fire, but he did not have an explanation.

An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year.

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Tesla’s ‘Emergency Drive Away’ function gets its first use in the real world

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Credit: Tesla

Tesla’s launch of the “Emergency Drive Away” function a few months back offered owners a safe option to evacuate an area if they were in reasonable danger. The function finally got its first use in the real world, but it appears it was by mistake.

A video shared by u/Joshalander in the r/TeslaLounge subreddit recorded the instance from his vehicle and said the incident took place in Austin this past weekend during the city’s F1 Race.

“Was charging around 6 AM this past Sunday in Austin before heading to the F1 race and heard a pop. Looked over and saw the new emergency drive-away feature in action. Genuinely felt bad for the dude when he got out and realized what happened, since he looked exhausted and only seemed to half-read the prompts.”

Emergency Drive Away unlatches the Supercharger connector from the vehicle, but still causes damage to both the car and the Supercharger. Tesla has said that it will cost up to $25,000 in repairs to have everything fixed back to normal.

Additionally, the company said that if it were not used in an emergency situation, the driver of the vehicle who activated the Emergency Drive Away feature would be responsible for all repair costs.

Tesla constitutes the following situations as reasonable justifications for activating the feature:

  • You face an immediate threat to your life or personal safety.
  • You must leave the area immediately.
  • Exiting the vehicle is unsafe.
  • Unplugging the charge connector would unreasonably delay your departure or expose you to a risk to your personal safety.

After using the feature, Tesla requires the driver to schedule Service so the car can be inspected.

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