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Tesla Semi and Roadster could be relying on a “battery breakthrough”
Elon Musk and Tesla have made some bold claims for the new Tesla Semi and Roadster. Those who understand batteries have been scratching their heads trying to figure out how the company can deliver the specs it’s promising – and concluding that the only possible way is some as-yet-unannounced advancement in battery technology.
Musk says the Tesla Semi will be able to haul 80,000 pounds for 500 miles, and recharge to 400 miles in 30 minutes, which would revolutionize the trucking industry. As for the Roadster, its promised 0-60 acceleration of 1.9 seconds effectively shuts down every one of the world’s baddest supercars, and its touted 620-mile range would be double that of any EV produced to date.
However, industry experts are questioning Tesla CEO Elon Musk’s touted range and charging capabilities, saying the specifications defy current physics and battery economics.
According to Bloomberg, analysts at Bloomberg New Energy Finance point out that Tesla Semi’s announced specs would require a battery capacity of between 600 and 1,000 kilowatt hours (6-10 times the size of the largest Model S battery). Using current technology, an 800 kWh battery pack would weigh over 10,000 pounds and cost more than $100,000. That’s just for the battery – Tesla has said its entire truck will start at $150,000. It seems plain that Tesla is counting on falling battery prices to square the circle. “The first Tesla Semis won’t hit the road until late 2019,” Bloomberg points out. “Even then, production would probably start slowly. Most fleet operators will want to test the trucks before considering going all-in. By the time Tesla gets large orders, batteries should cost considerably less.”
It isn’t just the capacity of the battery that’s causing analysts to wear out their calculators – Musk’s claim that the Tesla Semi will be able to add 400 miles of charge in 30 minutes would require a charging system 10 times more powerful than Tesla’s current Supercharger – which is already by far the most powerful in the industry.
Tesla Semi Megacharger port could support 1 MW of power.
“I don’t understand how that works,” said Bloomberg New Energy Finance EV Analyst Salim Morsy. “I really don’t.” Tesla’s current generation of Superchargers have a power output of 120 kilowatts and can add about 180 miles of range to a Model S battery in 30 minutes. To meet Tesla’s charging claim for the Semi would require the promised Megacharger to deliver an output of at least 1,200 kW.
Perhaps Tesla’s biggest bombshell is the promise that it will guarantee truckers electricity rates of 7 cents per kilowatt hour, which Bloomberg estimates could translate to fuel savings of up to $30,000 a year. Musk says that adding solar panels and battery packs at the charging stations will account for at least part of the cost reduction. However, BNEF’s Salim Morsy insists that Tesla will have to heavily subsidize those electricity rates – he estimates that Tesla will pay a minimum of 40 cents per kWh. “There’s no way you can reconcile 7 cents a kilowatt hour with anything on the grid that puts a megawatt hour of energy into a battery,” Morsy said. “That simply does not exist.”
Of course, that’s no different from what Tesla does for its current Supercharger network, offering free electricity to many customers, while paying almost $1 per kWh to produce it, according to Morsy’s estimate.
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And how about that Roadster? To deliver its promised range of 620 miles, it will need a 200 kWh battery pack, twice the size of Tesla’s largest currently available pack. Mr. Morsy predicts that Tesla will stack two battery packs, one on top of the other, beneath the Roadster’s floor.
Even with a double-decker pack however, it’s hard to escape the conclusion that Tesla is counting on improving battery tech to make the Roadster, like the Semi, feasible. Battery density has been improving at a rate of about 7.5 percent a year, and that’s without any major breakthrough in battery chemistry.
“The trend in battery density is, I think, central to any claim Tesla made about both the Roadster and the Semi,” Morsy said. “That’s totally fair. The assumptions on a pack in 2020 shouldn’t be the same ones you use today.”
A massive battery pack not only enables greater range – it’s also a key element in the Roadster’s world-beating 0-60 acceleration. Jalopnik’s David Tracy spoke with battery expert Venkat Viswanathan, a Mechanical Engineering Assistant Professor at Carnegie Mellon, who says that the 1.9-second figure actually seems reasonable.
Viswanathan explains that the power output of a motor is limited by the power draw from each battery cell. Because the Roadster’s pack is double the size, the power draw may not be that much more than that of a Ludicrous Model S.
Viswanathan told Jalopnik that the most modern battery cells offer specific energy of about 240 watt-hours per kilogram. Using that assumption, the Roadster’s 200 kWh battery pack should weigh roughly 1,800 pounds, a huge advance over the previous-generation Roadster. With clever use of lightweight materials, the Roadster could still come out under the nearly two-ton curb weight of the Nissan GT-R, an acceleration benchmark among sports cars.
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Viswanathan concludes that a 0-60 time of 1.9 seconds and a range of 620 miles are quite feasible, although there are several other factors that will come into play – much depends on the vehicle’s tires and aerodynamics.
Meanwhile, at least one analyst thinks Tesla’s latest revelations (or claims, or fantasies, depending on your point of view) have implications that go far beyond the Semi and the Roadster. Michael Kramer, a Fund Manager with Mott Capital Management, told Marketwatch that he suspects improved battery capacities and charging times could make their way into all future Tesla vehicles.
“I’d have to imagine that Tesla has figured out how to put this technology on all of their cars, which means every car could get a full charge in under 30 minutes,” Kramer wrote. Once the Model S “is equipped with the 200 kWh battery pack in the new Roadster, which I can’t imagine is too far down the road, the range issue for the Tesla is officially dead.” (Elon Musk has said that Models S and X will not get physically larger packs, but improved energy density could increase capacity while keeping the size of the pack the same.) Someday soon, Kramer says, “The Model S would likely be able to drive further on one charge than a car on a full tank of gasoline.”
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Note: Article originally published on evannex.com, by Charles Morris
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Elon Musk has declared that SpaceX has effectively solved one of Starship’s most persistent engineering challenges: the reliability of its heat shield tiles.
During the company’s first-ever Earnings Call, the SpaceX CEO stated:
“I don’t want to jinx it or anything, but I think I would call the heat shield problem solved at this point. All indications from data and visual inspection is we have solved it. That doesn’t mean we won’t make improvements, but we do not see any technical obstacles to achieving rapid reusability at this point.”
Starship’s heat shield consists of roughly 18,000 hexagonal ceramic tiles covering the windward side of the upper stage. These tiles form the thermal protection system that shields the vehicle’s stainless-steel structure from the extreme heat of atmospheric reentry.
Elon says he believes the heat shield problem with Starship is currently solved.
He called it “arguably the single biggest problem” pic.twitter.com/eEE9vM5zlz
— TESLARATI (@Teslarati) August 4, 2026
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During descent, atmospheric friction generates temperatures exceeding several thousand degrees Celsius and creates plasma flows capable of melting unprotected metal. The tiles absorb, radiate, and insulate against this energy, allowing the vehicle to survive and potentially fly again. Without a durable heat shield, full and rapid reusability, the cornerstone of Starship’s design for frequent launches, satellite deployments, and deep-space missions, would remain impossible.
The tiles have long been a source of difficulty. On earlier test flights, a significant number of tiles detached during ascent due to vibration, aerodynamic loads, and imperfect attachment methods using pins and adhesives. Gaps between tiles allowed hot plasma to infiltrate, causing secondary damage and hot spots on the underlying structure.
These issues echoed challenges faced by NASA’s Space Shuttle, whose ceramic tiles required extensive, labor-intensive inspections and replacements between missions, preventing rapid turnaround. SpaceX has iteratively improved materials, standardized tile shapes, refined attachment techniques, added secondary ablative layers, and tested sealing methods such as “crunch wrap” felt to close gaps.
Progress was visible across Flights 10–12, with steadily better tile retention, yet questions remained about whether the system could support the minimal-refurbishment goal of rapid reuse.
Flight 13 on July 24 provided the decisive evidence. Ship 40 flew a deliberately more demanding profile with higher dynamic pressure to stress the heat shield beyond typical operational loads. It successfully deployed 20 operational Starlink V3 satellites, the first such payload on a Starship mission, performed an in-space Raptor engine relight, and executed a controlled reentry.
Elon Musk sheds two new bits of detail on Starship after 13th test launch
Cameras on six of the satellites and onboard sensors captured extensive imagery and data of the shield throughout the flight. The ship then achieved its softest splashdown to date in the Indian Ocean, remaining intact and floating rather than breaking apart or exploding as on prior missions. This allowed drone inspections and continuous telemetry of the heat shield in near-real time.
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Post-flight analysis showed the majority of tiles remaining attached with only minor damage and limited plasma streaking at seams. Musk noted that the mission delivered “all the heat shield data we needed and then some.” Combined with visual inspections, these results underpinned his subsequent assessment that the core technical barriers to rapid reusability have been cleared. While refinements will continue, Flight 13 marked a pivotal step toward Starship’s operational future.
SpaceX COO Gwynne Shotwell outlined ambitious plans for Starlink Mobile during the company’s August 4 Earnings call, signaling a direct challenge to U.S. wireless giants like AT&T, T-Mobile, and Verizon.
Shotwell noted that the three companies generate roughly $600 billion in combined annual revenue. “I anticipate us to be able to acquire quite a few of their customers because I think our service will be better,” she said. “We will eliminate dead zones leveraging the satellites in orbit. It will be better during any natural disaster… I’m quite excited about Starlink Mobile.”
SpaceX President & COO Gwynne Shotwell on @Starlink Mobile and its impact on Verizon, AT&T and T-Mobile:
“Roughly, between them, $600 billion a year. I anticipate us to be able to acquire quite a few of their customers. Our service will be better. We will eliminate dead zones… pic.twitter.com/UYZUkrGc0L
— Sawyer Merritt (@SawyerMerritt) August 4, 2026
SpaceX intends to combine its satellite constellation with terrestrial infrastructure. The company has acquired about 65 MHz of spectrum from EchoStar and plans to deploy next-generation Starlink Mobile satellites in 2027, with upgraded service targeted for the end of that year.
Shotwell described the enhanced network, leveraging more satellites and spectrum, as potentially “100 times better” than the current direct-to-cell offering, which already supports basic texting and app-based voice/video in coverage gaps through partnerships. She also indicated plans for low-cost cellular base stations that could integrate with existing Starlink dishes, creating a hybrid system for broader capacity in urban, suburban, and rural areas.
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For the general public, Starlink Mobile promises significant advantages. Satellite connectivity can fill gaps where traditional cell towers fail, delivering service in remote locations, mountains, or during outages caused by storms, wildfires, or infrastructure damage—conditions in which ground networks often collapse.
Users could enjoy more consistent coverage without relying solely on dense tower builds, potentially at competitive prices as SpaceX scales. The hybrid approach aims to support full mobile services, including higher-speed data, while working with unmodified smartphones over time.
These developments revive long-standing but unfounded rumors of a Musk-developed “Tesla phone.” Speculative claims of a “Pi Phone” or similar device with built-in Starlink connectivity have circulated for years on social media, often featuring fabricated images and details. Elon Musk has repeatedly denied any such plans, stating Tesla has no intention of entering the smartphone market unless forced by extreme circumstances with app stores.
No official product, filings, or development announcements have ever materialized; the rumors remain hoaxes.
The announcement quickly pressured telecom stocks. Shares of AT&T, Verizon, and T-Mobile fell between roughly 2 and 4 percent in after-hours and premarket trading as investors weighed the competitive threat from a hybrid satellite-terrestrial network.
While execution challenges remain—spectrum deployment, infrastructure rollout, and regulatory hurdles—Shotwell’s remarks mark SpaceX’s clearest signal yet of entering the consumer mobile market as a full competitor.
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Venture capitalist Chamath Palihapitiya has cautioned investors shorting SpaceX shares, drawing a direct parallel to the intense short-selling pressure Tesla faced in its early public years.
Responding to reports of elevated short interest in the newly public rocket, satellite, and AI company, Palihapitiya noted that similar dynamics played out with Tesla, where aggressive short sellers ultimately “went broke.”
SpaceX (NASDAQ: SPCX) went public on June 12, 2026, in the largest IPO on record, pricing at $135 per share. Shares quickly surged to an all-time high of $225.64 just days later, briefly implying a valuation exceeding $2 trillion. The stock has since retreated sharply amid valuation concerns, lockup expiration fears, and broader market dynamics.
By early August, it traded near $108–$125, representing a roughly 50 percent decline from the peak and bringing the market capitalization closer to the $1.5–1.7 trillion range. On August 4, shares closed up more than 9 percent at $125.33 ahead of earnings before facing pressure in after-hours and premarket trading.
Short interest has climbed dramatically. According to S3 Partners data widely cited in market reports, short positions reached approximately 219.3 million shares by late July, about 34 percent of the limited public float of roughly 640 million shares, and represented a notional value of around $24.6 billion.
Utilization of shares available to borrow hit 95 percent, with borrow fees rising. This level of shorting exceeded the dollar value of short bets against Tesla at the time and built rapidly ahead of two catalysts: the company’s first post-IPO earnings and an August 6 lockup expiration that could free up to 911.5 million additional shares.
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CEO Elon Musk has issued warnings of his own. In mid-July, as short interest approached one-third of the float, he posted that “the survival probability of firms who maintain a significant short position in SpaceX over time is very low,” reiterating his view that the company could ultimately be worth more than Earth if it achieves its goals.
On August 4, just before earnings, Musk responded to the latest short-interest data by saying, “I try to warn them, but they just double down.”
SpaceX delivered its first quarterly results as a public company after the close on August 4. Second-quarter revenue rose 92 percent year-over-year to $7.8 billion, beating consensus estimates near $6.8–6.9 billion.
The net loss narrowed to $541 million, or 9 cents per share, better than the roughly 23–24 cent loss expected. Starlink/connectivity contributed about $4.3 billion (up 66 percent), while the AI business generated $2.6 billion (up roughly 250 percent). Capital expenditures were heavy at $18.4 billion, largely tied to AI infrastructure. Management projected a $100 billion annualized revenue run rate by year-end 2026 and outlined a path toward $1 trillion in annual revenue by 2030.
The combination of Chamath’s historical reminder, Musk’s repeated alerts, and the company’s ambitious growth targets underscores the high-stakes debate surrounding SPCX. Short sellers are positioned for near-term supply pressure from the lockup, while long-term bulls point to Starlink scale, Starship progress, and AI compute expansion as reasons the bears may ultimately face the same fate as many early Tesla skeptics.
SpaceX has solved Starship’s biggest challenge, Elon Musk says
SpaceX is coming for wireless giants with Starlink Mobile
