SpaceX
SpaceX begins static Starhopper tests as Raptor engine arrives on schedule
SpaceX has officially begun static ground testing of Starhopper, a full-scale pathfinder Starship prototype meant to support an early series of Raptor-powered hop tests at SpaceX’s South Texas launch site. Simultaneously, the second completed Raptor engine arrived at the site on Monday, March 11th, confirming CEO Elon Musk’s March 8th tweets about the delivery.
While reasonably routine for any rocket test program, the first tanking test of Starhopper effectively marks the first time that SpaceX has begun tests with a more or less fully integrated Starship (previously BFS). Likely performed with liquid nitrogen instead of liquid oxygen/methane, the first few tanking tests will be used to determine the quality of the prototype’s stainless steel tanks – built en
In November 2016, SpaceX began propellant-loading tests of its first finished full-scale Starship (then Big Falcon Spaceship) hardware, a massive carbon composite liquid oxygen tank stretching 12 m (~40 ft) in diameter. Over the course of 2017, SpaceX transitioned from liquid nitrogen to liquid oxygen and ultimately conducted one final burst-test in which the composite tank was pressurized until it exploded, ending full-scale BFR composite testing with a bang. Within 6-12 months, Musk had come to the conclusion that a stainless steel BFR would ultimately be a superior path forward for the rocket and spaceship and attempted (apparently successfully) to get his team of R&D engineers on board with such a radical change so late in the development phase.
Despite the fact that that radical design departure may have occurred as few as 6-8 months ago, SpaceX engineers and technicians have accomplished an extremely rapid development program that will – in part – culminate in the hopefully successful hop testing of Starhopper, the first Starship prototype. While more of a rough testbed than an actual representation of the hardware and structures that will be required for a reusable orbital-class Starship, Starhopper has at least acted as a crash course (either technically or organizationally) on fabricating and assembling stainless steel aerospace structures, a material largely foreign to SpaceX flight hardware prior to late 2018.
Although the early vehicle was less than encouraging, as was the demise of its nosecone as a consequence of improper planning and/or bad workmanship, Starhopper as it now stands might actually be flightworthy in the context of suborbital, subsonic hop tests. Powered by the same or similar Raptors that would power orbital prototypes, Starhopper’s hop tests would optimally provide a wealth of experience and engineering data for both building 9 meter/30 foot-diameter stainless steel rocket sections and operating full-scale Raptor engine(s) in actual flight configurations. Extensive testing with Raptor will help to ensure that the fit and finish of the new engine’s flight-grade avionics and hardware are up to the challenge of safe, reliable, and gentle operations for a nominally crew-rated launch vehicle and spacecraft.
Around two days after Starhopper was briskly transported from its build site to SpaceX’s brand new launch facility, local Twitter account @SPadre (short for South Padre Island) posted a video of tanking test that occurred on March 11th, capturing the sound of venting as the liquid involved turned to gas inside its propellant tank(s). The fact alone that the person behind the camera was allowed to be where they were during the test all but guarantees that this first test was performed with an inert liquid, most likely liquid nitrogen given a massive delivery that occurred the day before (March 10th). In no conceivable world would SpaceX or local law enforcement willingly allow for Starhopper to be loaded – for the first time ever – with even a partial load of liquid methane or liquid oxygen with bystanders barely a few hundred feet distant.
When SpaceX gets to the point that they are confident enough in the structural integrity of Starhopper to begin wet dress rehearsals and tests with actual propellant, it’s a safe bet that the company will cooperate with local law enforcement to block off the lone access road to a distance of at least 1-2 miles, if not more. It’s unclear if local homeowners and residents will be forced to vacate the adjacent Boca Chica Village during testing, but chances are good that nobody will be within several thousand feet of Starhopper when those propellant loading tests begin, let alone actual static fire activity once Raptor(s) are installed.
According to an official SpaceX statement on the progress, propellant load tests and static fires could begin “in the days ahead”, although the spokesperson was under the impression that those tests – as well as initial hop tests – “[would] not be visible from offsite”. Unless SpaceX plans to draw a keep-out zone with a radius of multiple miles, interested observers will almost certainly be able to get close enough to at least catch a glimpse of Starhopper, but the statement still offers an idea of just how focused the company will be on safety during these early tests.
Check out Teslarati’s Marketplace! We offer Tesla accessories, including for the Tesla Cybertruck and Tesla Model 3.
SpaceX’s Raptor engine family has steadily increased sea-level thrust while simultaneously reducing mass, turning iterative engineering gains into substantially higher performance for the Super Heavy booster. CEO Elon Musk shed more light on how powerful Raptor 4 will be, and it’s pretty crazy.
Raptor 1 delivered 185 metric tons of thrust at roughly 2,080 kilograms, while Raptor 2 raised that to 230 tons while cutting mass to about 1,630 kilograms. SpaceX data for Raptor 3 lists a target of 280 tons at 1,525 kilograms (with further reductions in associated vehicle hardware), while operational flight ratings have been cited near 250 tons.
This morning, Elon Musk stated that Raptor 4 is expected to reach 300 tons of sea-level thrust at roughly the same mass as Raptor 3. Across these versions, thrust has risen by more than 60 percent from the first engines while engine mass has fallen, producing a sharp improvement in thrust-to-weight ratio. This is a true testament to how great SpaceX engineering has been:
🚀 Elon says Raptor 4 will make 300 tons of thrust at sea level at roughly the same mass as Raptor 3.
How far Raptor has come:
Raptor 1: 185 tf, 2,080 kg
Raptor 2: 230 tf, 1,630 kg
Raptor 3: 250 tf, 1,525 kg
Raptor 4: 300 tf33 on Super Heavy = ~9,900 tf, nearly 3x Saturn V https://t.co/HQDswZhyvL
— TESLARATI (@Teslarati) October 26, 2026
With 33 engines on SuperHeavy, the jump from earlier versions to a 300-ton Raptor 4 would produce roughly 9,900 metric tons of total liftoff thrust, nearly three times the Saturn V’s approximately 3,400 metric tons from its five F-1 engines.
This is not just a larger number on a data sheet, either, as sea-level thrust is the force available the moment the vehicle leaves the pad. This is when it is heaviest and still deep in Earth’s gravity well and dense atmosphere.
Higher levels of sea-level thrust directly improves the initial thrust-to-weight ratio of the full stack. A higher ratio produces faster acceleration off the pad, which shortens the time the rocket has to spend fighting gravity, and gravity losses during the first minute or two of the flight are a major drain on total available delta-v. Every second shaved off of that early climb preserves more propellant energy for reaching orbital velocity or for carrying extra payload.
Because Super Heavy’s engine count is constrained by vehicle diameter and packing density, increasing thrust per engine is the most straightforward way to raise total liftoff performance without redesigning the booster structure or design.
The same-mass target for Raptor 4 is equally important. Holding engine mass roughly constant while raising thrust improves the engine’s own thrust-to-weight ratio and reduces the structural and propellant mass fraction that must be carried solely to support the engines.
Earlier Raptor iterations also simplified or eliminated extensive vehicle-side hardware such as heat shields. These gains compound: more force for less installed mass leaves additional capacity for propellant, payload, or operational margins such as engine-out capability.
For Starship’s architecture, the practical effects are large. Greater liftoff thrust supports heavier vehicles, larger propellant loads, and higher payloads to low Earth orbit, figures SpaceX has targeted in the 100-plus-ton reusable range. That capacity underpins orbital refueling, lunar missions, and eventual Mars cargo and crew flights.
Continued growth in sea-level thrust therefore tightens the gap between theoretical rocket performance and the high flight rates and reusability needed to make large-scale space transport practical.
Tesla expanded its Robotaxi geofence in Houston, Texas, today, enlarging the service area and drawing a new rocket-shaped boundary across the city’s northwestern and central parts.
Although CEO Elon Musk said it was just a coincidence, the expansion seems to be an ode to SpaceX and its potential merger with Tesla.
🚨 Tesla has just expanded its Robotaxi geofence in Houston
It looks a lot like a rocket — we all remember the shape in Austin 🤣 https://t.co/cFOPEuiJ4u
— TESLARATI (@Teslarati) October 26, 2026
The official Tesla Robotaxi account announced the change with the lines “Houston, we have liftoff” and “Bigger service area now live,” pairing them with a map overlay.
The prior white geofence, roughly 25 square miles covering Jersey Village, Harvest Bend, and the Willowbrook corridor along U.S. 290 and State Highway 249, now sits inside a larger blue zone that stretches southeast toward Bellair and closer to central Houston.
Houston’s Robotaxi service launched on April 18, 2026, the same day as Dallas, as Tesla’s first unsupervised public expansion beyond Austin. From the start, the vehicles were Model Ys running without anyone in the front seats, booked through the dedicated Tesla Robotaxi app and open to the public inside the geofence.
Trackers measured the initial zone at about 25 square miles; by late September it had not grown substantially. Community and registry data indicated a modest local fleet of unsupervised Model Ys, while dozens to nearly 200 Cybercabs, the purpose-built, steering-wheel-free two-seaters, have been spotted staging and testing in Houston lots, though public Cybercab rides remain limited to Austin for now.
Across the broader Robotaxi program, Tesla began public Robotaxi rides in Austin in June 2025, as a small geofence and vehicles with safety monitors became available for a ride-hailing service. Later on, Tesla removed the monitors and steadily expanded the service area until it covered most of the Austin metro area.
Unsupervised Robotaxi services now run in six cities: Austin, Dallas, Houston, Miami, Orlando, and Tampa. Cumulative driverless miles reported by the company have reached several million. The Cybercab entered public service in Austin in early September 2026 and has scaled rapidly there. The company has also said that Dallas is next for Cybercab rides in November, with further cities and 24/7 hours targeted by year-end, plus fleet-operator sales of the vehicle.
Waymo also operates a fully driverless service in Houston, which has been open to the public since August of this year.
The Houston expansion continues Tesla’s pattern of starting with tightly controlled validation zones before widening coverage as real-world data accumulates, while the rocket motif on the map underscores the company’s habit of injecting visual flair into its autonomy rollout.
Riders inside the new boundary can request unsupervised Model Y trips in the Robotaxi app; exact operating hours and further Cybercab availability remain subject to app updates and company statements.
Elon Musk
The Starship moon landing number NASA and Elon Musk can’t agree on
Musk disputes NASA estimate of 22 Starship launches for Moon landing, predicting 6 to 8.
Elon Musk is disputing a new NASA safety panel estimate of how many Starship launches it will take to put astronauts on the Moon, saying the real number will be less than half the panel’s figure.
On Thursday, NASA’s Aerospace Safety Advisory Panel held its quarterly public meeting. Panel member Charlie Precourt, a former NASA astronaut, flagged the fueling process for SpaceX’s lunar lander as a major risk for Artemis IV, the mission planned to land a crew on the Moon in 2028. “We need to keep our eyes on numerous required fuelings for the lander,” Precourt said, according to Ars Technica. “I think the last estimate is around 22 flights.”
Ars Technica’s Eric Berger posted the comment on X, and Musk replied. “That’s way too high,” Musk wrote. “Actual number will be more like 6 to 8.”
The disagreement comes down to a basic problem with sending a ship as large as Starship to the Moon. Starship burns nearly all of its propellant just reaching Earth orbit, so it cannot continue on to the Moon without stopping for a refill. SpaceX’s answer is a gas station in space. First, a Starship that works as a storage tank, called a depot, is launched into orbit. Then a series of tanker Starships launch one at a time, dock with the depot and pump their leftover propellant into it. Once the depot is full, the lunar lander version of Starship launches, docks, fills up and heads for the Moon.
Every tanker trip is its own full rocket launch, which is why the count matters. More launches mean more time, more cost and more chances for something to go wrong before astronauts ever leave Earth. Berger estimated that even if SpaceX reaches twice weekly Starship launches by the end of 2027, filling a depot at the panel’s number would still take roughly three months.
How many tankers are needed depends mostly on how much propellant each one can carry to orbit and how much is lost along the way. Starship’s fuel and oxygen are stored at extremely cold temperatures, and some of it slowly boils off while waiting in orbit. More is lost in each transfer. NASA appears to be working from what Starship can lift today, while Musk’s range assumes a more capable rocket.
Musk has pushed back on higher counts before. In 2021, after a government document suggested 16 launches, he called that “extremely unlikely” and said eight tankers would be the most required.
Much of the answer depends on hardware SpaceX has not finished flying. As Teslarati noted earlier this year, the company plans to carry out the refueling process with its upgraded V3 Starship, and Precourt described Artemis IV as carrying “a large number of firsts.” He also praised NASA Administrator Jared Isaacman’s team for working to clear obstacles for both SpaceX and Blue Origin, whose Blue Moon lander does not rely on orbital refueling for its first mission.
Tesla has a Cybercab problem nobody saw coming
How SpaceX Is raising Raptor’s sea-level thrust while holding engine mass steady
