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SpaceX’s orbital Starship prototype gets frosty during first successful ‘cryoproof’

Starship S20 lets off some steam with a vent 200+ feet long during its first cryoproof test. (NASASpaceflight - bocachicagal)

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For the first time, SpaceX has put the first orbital-class Starship – a prototype known as Ship 20 (S20) – through a routine cryogenic proof test, filling the rocket with several hundred tons of liquid nitrogen to simulate its explosive propellant.

While it’s impossible to jump to conclusions before members of the public can return to the pad to take photos or CEO Elon Musk takes to Twitter to discuss the results, Ship 20’s first ‘cryoproof’ appears to have been largely successful [Edit: Musk has confirmed that the test went well]. Relative to the almost three-dozen cryoproofs SpaceX has completed with more than a dozen other Starship, booster, and test tank prototypes over the last two years, though, Ship 20’s first major test still has some oddities.

Historically, every cryoproof of a full Starship prototype has been visually unique and virtually impossible to predict. Without any direct insight from SpaceX or Elon on the objectives, plan, or timeline of tests, the process of watching tests (via unofficial webcams, of course) and attempting to interpret why certain things look the way they do or what’s going on at any given moment is a bit trying to interpret eroded hieroglyphics.

At the most basic level, cryogenic tanking tests – whether with Starship, Super Heavy, or test tanks and liquid oxygen (LOx)/methane (LCH4) propellant or neutral liquid nitrogen (LN2) – are fairly simple. The vehicle is attached to pad systems, powered on, and partially or fully loaded with cryogenic fluids. Once the desired test objectives are achieved or attempted, the vehicle is then detanked (drained of propellant or LN2).

Thanks to the fact that they’re incredibly cold (-160 to -200C; -260 to -330F), the LOx/LCH4 or LN2 Starships are filled with quickly chill the thin steel tanks containing them. With no insulation to speak of, that supercooled steel then freezes water vapor out of the humid South Texas air, creating a layer of frost/ice that generally follows the level of the cryogenic liquids in Starship’s tanks. Throughout that process, those cryogenic liquids inevitably come into contact with ambient-temperature Starship tanks and plumbing (white-hot in comparison) and warm up, boiling off into gas as a result.

A gaseous chemical is far less dense than its liquid form, meaning that the pressure inside Starship’s fixed tanks can rapidly become unmanageable after even a small amount of boiloff. To maintain the correct tank pressures, Starship – like all other rockets – occasionally vents off the gas that forms. And thus, the two main methods of interpreting the hieroglyphics that are cryoproof tests: frost levels and venting.

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Compared to earlier prototypes, Starship S20’s first cryoproof has been… unusual. Most notably, SpaceX began loading the rocket with liquid nitrogen around 8pm CDT. Its LOx (bottom) and CH4 (top) tanks were then slowly filled to around 30-50% of their full volume over the next hour. However, rather than detanking, SpaceX then partially drained the methane tank but filled the LOx tank further before leaving the LOx tank more or less fully filled for more than two hours, occasionally topping it off with fresh liquid nitrogen.

Several giant vents almost four hours after testing began tricked even the most experienced of ‘Tank Watchers.’

Then, almost four hours after LN2 loading began, Starship performed several massive vents. Ordinarily, given the hours of testing prior, those vents would have assuredly been detank vents – effectively depressurizing Starship’s tanks as they’re drained of fluid. However, those vents instead coincided with the rapid loading of one or several hundred more tons of LN2, seemingly topping off Starship S20 in the process. Around that point, it’s possible that SpaceX began the pressure testing portion of Ship 20’s cryoproof, (mostly) closing the rocket’s vents and allowing the pressure to gradually increase to flight levels (and maybe even higher).

Many, many months ago, when SpaceX was deep into cryoproofing the first full-size Starship prototypes, Musk revealed an operating pressure goal of 6 bar (~90 psi). Ships were eventually successfully tested above 8 bar (~115 psi), giving Starship a healthy ~30% safety margin. As the first orbital-class Starship prototype, Ship 20 likely needs to hit those tank pressures more so than any ship before it to have a shot at surviving its orbital launch debut and orbital-velocity reentry attempt.

Starship S20’s first (aborted) cryogenic proof test attempt, September 27th. (NASASpaceflight – bocachicagal)
A demonstration of the kind of forces and pressures involved with SpaceX’s building-sized Starship SN1 prototype in February 2020.

Beyond the basics of cryoproofing, Starship S20 also marked a crucial step forward on September 29th/30th, becoming the first ship to complete a cryoproof test with a full heat shield installed. While it’s impossible to judge exactly how well S20’s ~15,000-tile heat shield performed, views from public webcams showed no obvious signs of tiles shattering and falling off as Starship repeatedly cooled and warmed – contracting and expanding as a result. Additionally, still in contact with the air, the steel tank skin under a majority of Ship 20’s tiles would have likely covered itself in a layer of frost and ice, but the heat shield appeared to handle that invisible change without issue.

It’s possible that dozens or hundreds of tiles bumped together and chipped or cracked in a manner too subtle to be visible on LabPadre or NASASpaceflight webcasts, but that can only be confirmed or denied when the road reopens and local photographers can capture higher-resolution views of Starship. For now, it appears that Ship 20’s first cryoproof was highly successful, hopefully opening the door for Raptor installation and static fire testing in the near future. Stay tuned for more!

Update: As is almost tradition by now, SpaceX CEO Elon Musk didn’t take long to tweet about the results of Starship S20’s first cryoproof, confirming that the “proof was good!”

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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’s Roadster appearance at SpaceX has merger watchers talking

Tesla’s next generation Roadster was spotted at SpaceX’s Hawthorne headquarters, two weeks after its unveiling.

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The Roadster’s rear wing, one of the aerodynamic elements Tesla pairs with a fan-based downforce system. (Image: Tesla)

Tesla’s next generation Roadster turned up at SpaceX’s headquarters in Hawthorne, California on Wednesday, less than two weeks after the car flew off a ramp at its unveiling in Texas.

Photos shared on X by SpaceX Engineer (@DeannaRiceSPCX) show the new Roadster parked outdoors beside the famed Falcon 9 that stands outside company headquarters at the corner of Crenshaw Boulevard and Jack Northrop Avenue. Rocket B1019 was the first orbital-class booster ever to land after a launch on December 21, 2015 after it sent 11 Orbcomm satellites to orbit and then flew back to Landing Zone 1 at Cape Canaveral, which would be the first landing in what became SpaceX’s reusable rocket program. SpaceX chose not to fly it again. After a test fire in Florida, the booster was shipped to Hawthorne and raised upright as a permanent monument in August 2016, as Teslarati reported at the time. Putting the Roadster, which flies on SpaceX cold gas thrusters, next to the rocket that started SpaceX’s landings is symbolic in itself.

The Thrust and Rocket versions of the Roadster use cold gas thrusters fed by composite overwrapped pressure vessels, the same type of tank SpaceX flies on Falcon 9, and Elon Musk described the car as the work of Tesla and SpaceX engineers working together. Tesla lists 0 to 60 mph in under 0.9 seconds for Thrust and under 0.59 seconds for Rocket, while the base Performance model relies on a fan and ground sealing system for grip, as Teslarati detailed in its breakdown of the three Roadster configurations.

Tesla has kept the car in the spotlight since the October 15 event near Waco. Last week, the company posted a video of the Roadster’s fighter jet inspired cockpit, including a Track Mode screen with a “Thruster · 5,500 PSI” readout, which we covered in our look at the Roadster’s center display. Musk also said owners will be able to ask the car to perform the stunts autonomously, and promised a looping track at Tesla’s Texas headquarters.

The visit comes as special committees at Tesla and SpaceX weigh a possible merger, a step Musk confirmed on SpaceX’s third quarter earnings call. The Roadster, built on SpaceX hardware, has become one of the clearest examples of the two companies already building products together.

Musk said at the unveiling that Roadster production will begin in 2028. Reservations are open with a $50,000 payment, Thrust is listed as a limited release and Rocket is invite only. Tesla says the car is not approved for public road use.

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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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