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SpaceX begins testing first flightworthy Super Heavy booster
More than three months after the building-sized Starship booster’s latest return to Starbase’s orbital launch site, SpaceX has finally begun the process of testing what CEO Elon Musk says is still the first flightworthy Super Heavy.
After completing a number of pad tests in the days prior, SpaceX began filling Super Heavy Booster 4 (B4) with liquid nitrogen – supplied by the first orbital-class Starship launch – for the first time on December 17th. It’s unclear exactly what was done during the test but regardless of what transpired, the test and B4’s survival were a major, long-awaited milestone for both the Starship booster and the orbital launch site (OLS).
At this point in time, the general consensus among close followers of SpaceX’s Starship program is that the unprecedented amount of time it’s taken the company to complete Booster 4’s first test was not because of the rocket itself but rather because the orbital launch site needed to fully test it had yet to be completed. While it was SpaceX’s choice to not perform some kind of initial testing with B4 at one of the site’s two suborbital test and launch mounts, it’s clear that the company ultimately concluded that Super Heavy Booster 3’s successful July 2021 tests – including a cryogenic proof virtually identical to Booster 4’s first test – made such partial testing redundant.
Put a different way, SpaceX must already be confident enough in the quality of the first few Super Heavies rolling out of its Starbase factory to deem it unnecessary to verify the structural integrity of the first truly completed Super Heavy booster before putting the one and only orbital Starship launch site directly in the line of fire. Nonetheless, depending on how far Super Heavy Booster 4’s first cryogenic proof test went, it appears that SpaceX’s presumptions were correct.
On December 17th, SpaceX subjected Super Heavy B4 to a cryogenic proof test about twice as ambitious as B3’s, filling the booster maybe a sixth of the way with a few hundred tons of liquid nitrogen (LN2). What isn’t clear is if that test also raised the booster’s propellant tanks to flight pressures (6-8 bar or 90-115 psi). If Booster 4 did reach those pressures, the test is even more significant – partially proving that the rocket is ready for flight. On December 21st, SpaceX performed a similar series of cryogenic tests, again partially filling Booster 4 with about the same amount of liquid nitrogen but doing so two or three times in a row. Again, the Super Heavy survived the several-hour ordeal without any obvious issues. Still, a number of additional tests – some even more important – are still in front of SpaceX and Super Heavy B4.
The most obvious is simple enough: SpaceX needs to fully fill a Super Heavy booster for the first time. Depending on the storage situation, that process will likely begin by filling Booster 4 with about 2500 tons (5.5M lb) of liquid nitrogen (LN2) – about two-thirds full. If SpaceX also temporarily fills one of the orbital tank farm’s liquid oxygen (LOx) or methane (LCH4) tanks with nitrogen, it could fully load Booster 4 with around 3500 tons (7.7M lb) of nitrogen. At least according to SpaceX’s own website, that’s about the same weight as the propellant (3400t/7.5M lb) Super Heavy is designed to lift off with. If that full cryoproof goes well, SpaceX will then likely perform one or several wet dress rehearsals, ultimately filling Booster 4 with approximately 2900 tons (6.4M lb) of cryogenic oxygen and 500 tons (1.1M lb) of cryogenic methane.
Finally, SpaceX will probably kick off static fire testing, likely beginning by igniting just one or a few of Super Heavy’s many engines. Eventually, that process could culminate in the ignition of all 29 of Booster 4’s Raptors, briefly producing a bit less than 5400 tons (~11.9M lbf) of thrust – 50% more powerful than NASA’s retired Saturn V Moon rocket.
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According to Elon Musk, despite a number of recent signs and reports to the contrary, SpaceX still intends to fly Booster 4 and Ship 20 on Starship’s first orbital-velocity launch attempt, so the scope and scale of testing are only likely to grow over the next several weeks.
Elon Musk
The Boring Company’s newest tunnel vehicle runs on Tesla parts and no one is driving it
The Boring Company’s new tunnel vehicle runs on Tesla Model 3 batteries and drive units.
The Boring Company just introduced a new piece of hardware, and it runs on parts pulled straight from a Tesla showroom. Liner Truck 3, unveiled in a post from the tunneling company’s official X account, is an all electric vehicle built around Tesla Model 3 battery packs and drive units, purpose built to move concrete tunnel segments to the boring machine face without a single person underground.
Introducing Liner Truck 3 — our latest fully electric tunnel vehicle.
– Tesla Model 3 battery and drive units
– Transports 22,000+ lb of concrete segments to the boring machine
– 28 miles of range
– 12 mph max operating speed
– Remotely piloted from Global OCC in Texas, with… pic.twitter.com/XB7FgSXnpy— The Boring Company (@boringcompany) August 7, 2026
The job itself is unglamorous but critical. Each precast segment run weighs more than 22,000 pounds, roughly the load of a full cement mixer, and Liner Truck 3 hauls that weight repeatedly between the surface staging area and wherever the Prufrock machine happens to be cutting.
The Boring Company said Liner Truck 3 is piloted remotely out of its Global Operations Control Center in Texas, extending the Zero-People-In-Tunnel approach the company has spent years building toward. An earlier version of a ZPIT liner truck was already tested at the company’s Bastrop, Texas research tunnels, and a factory tour released last month showed an employee flying a fully loaded liner truck with a PlayStation controller. Liner Truck 3 looks like the production version of that same idea, cleaned up and pushed into daily use.
The timing lines up with a company digging in more places than it ever has before. The Boring Company now has multiple Prufrock machines active or arriving in Nashville, where Music City Loop construction has been accelerating since February, and its Vegas Loop network keeps adding tunnel mileage on a near monthly basis. Every one of those projects depends on getting concrete segments to the cutting face fast enough to keep the boring machine from idling, which is exactly the bottleneck Liner Truck 3 is designed to remove.
It also reinforces something Tesla owners have watched happen gradually across Musk’s companies: passenger car hardware finding a second life in heavy equipment. Model 3 drive units already move people through the Vegas Loop, and now the same components are hauling concrete underground in Nashville and wherever The Boring Company digs next. Whether that kind of component reuse extends further into TBC’s equipment lineup, or into other Musk owned industrial hardware, is the next thing worth watching.
SpaceX stock did the opposite of what most of Wall Street expected this week, when the day designed to be its most dangerous turned into a rally, and the rally kept going.
Thursday marked the first major lockup expiration since SpaceX’s June IPO, making roughly 911.5 million insider held shares eligible to trade for the first time, more than doubling the company’s public float. Analysts and short sellers had spent weeks bracing for a flood of selling, especially after the stock fell 13 percent following its first earnings report as a public company on Tuesday. Instead, shares rose 6.1 percent Thursday to close at $114.92, and by Friday they were trading near $129, up more than another 12 percent on the day.
SpaceX shorts get warned by Musk ally, echoing Tesla’s early struggles
The setup made the outcome notable. Short interest had climbed to roughly 34 percent of the float heading into earnings, among the highest of any large cap stock, with about 95 percent of available shares to borrow already on loan. CEO Elon Musk warned short sellers twice in the weeks before the lockup, writing on X that “the survival probability of firms who maintain a significant short position in SpaceX over time is very low,” then following up on the morning of earnings with “I try to warn them, but they just double down.”
When the newly unlocked shares hit the market and the selloff never showed up, some of that short position appears to have started unwinding. TipRanks reported that options activity shifted toward bullish strategies like put selling and risk reversals following the rally, with roughly $600 million in options premium trading Thursday alone. Retail buyers also stepped in during the earnings dip, according to Vanda Research.
The fundamentals behind the stock have not changed much in a week. SpaceX’s revenue nearly doubled year over year to $7.8 billion, with Starlink subscribers doubling to 12 million and the company’s AI segment growing 247 percent. What spooked investors on Tuesday was the spending side. Capital expenditures jumped to more than $18 billion for the quarter, up from $2.8 billion a year earlier, with AI investment alone rising from $749 million to $15.8 billion. Wall Street remains split on whether that spending is building infrastructure SpaceX needs or outrunning what the business can currently support, a debate Teslarati has tracked since shares first came under pressure.
None of that resolves the bigger question hanging over the stock. Thursday’s release was only the first of nine staggered lockup tranches, with roughly $800 billion worth of additional shares scheduled to become eligible through October, and Musk’s own stake stays locked until next June. If this week is any indication, the market is treating that supply as something it can absorb rather than something to fear, at least for now.
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The Boring Company’s newest Vegas Station has a permit quietly waiting behind it
Sahara Las Vegas opened a new Vegas Loop station, joining an exclusive two resort transit club.
Sahara Las Vegas opened a new Vegas Loop station Thursday, giving The Boring Company’s underground transit system its northernmost stop yet on the Strip. The station sits at Sahara’s Paradise Road entrance, on the southeast corner of Las Vegas Boulevard and Sahara Avenue, and connects riders to the Las Vegas Convention Center, other Strip resorts on the network and, eventually, Harry Reid International Airport.
The addition makes Sahara the second resort, after Fontainebleau opened its own station in January, to get a stop built at street level rather than tucked into the property itself. Sahara now joins Westgate as the only two Strip resorts offering both a Vegas Loop station and a stop on the Las Vegas Monorail, giving guests two separate ways to get around without leaving the property.
The Boring Company just doubled its tunneling power in Nashville
The bigger news buried in Thursday’s announcement is what comes next. Boring Company has already secured its first permit to tunnel north of Sahara Avenue, extending the network beyond where it currently ends, even though permits to push the Loop toward downtown Las Vegas still haven’t been granted. Crews are also working on a two mile dual tunnel line running from Westgate to a planned station at 4744 Paradise Road, just north of Tropicana Avenue, that Las Vegas Convention and Visitors Authority CEO Steve Hill has said the company hopes to open in time for November’s Las Vegas Grand Prix.
Ridership has grown alongside the buildout. The Loop moved roughly 82,000 passengers during CONEXPO in early March, a total the company highlighted on its own X account at the time, and the system has now carried more than 4 million passengers through 11 open stations since it began running in 2021. The airport connector tunnels, meant to give the Loop a direct link to Harry Reid, have slipped past their original first quarter target and remain under construction, with Boring Company director Mike Baier saying that a full opening is still a few months out.
For Sahara, the calculation is straightforward. Convention traffic drives a large share of Loop ridership, and a station at the property’s front door gives conventiongoers one more reason to book rooms on the Strip’s north end instead of closer to the convention center itself.
The Boring Company’s newest tunnel vehicle runs on Tesla parts and no one is driving it
Elon Musk and SpaceX shrugs off the trading day Wall Street feared most
