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SpaceX hangar packed with Falcon Heavy Block 5 boosters for early April debut

Two brand new Falcon Heavy side boosters were spotted inside SpaceX's Pad 39A hangar in a SpaceX video covering preparations for Crew Dragon's launch debut, February 28th. (SpaceX)

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For a company that rarely reveals anything without explicit intent, a February 28th video posted by SpaceX during the lead-up to Crew Dragon’s launch debut featured a surprise cameo: two Block 5 side boosters meant to support Falcon Heavy’s commercial debut and second launch ever.

Likely a subtle nod to close observers and fans, the inclusion of Falcon Heavy is a perfect bit of foreshadowing for the next launch set to occur from Pad 39A after Crew Dragon’s flawless orbital debut. As of now, Falcon Heavy Flight 2 is settling in on a potential launch as early as the first week of April, although delays during the rocket’s critical preflight processing and static fire test are about as likely as they were during the vehicle’s inaugural mission. If the rocket’s first launch and booster recoveries are fully successful, both side boosters (and perhaps the center core) could fly for a second time as few as two months later in June 2019.

A number of photos taken by Instagram users visiting Kennedy Space Center appear to indicate that SpaceX has more or less completed the reconfiguration of Pad 39A’s transporter/erector (T/E), modifying the base with additional hold-down clamps to account for three Falcon boosters instead of the usual one. Ten days after the successful launch of Falcon 9 B1051 in support of Crew Dragon’s first mission to orbit, it’s likely that additional work remains to ensure that 39A is fully refurbished and reconfigured for Falcon Heavy.

For the heavy-lift rocket’s commercial debut and second flight ever, SpaceX is likely to be exceptionally cautious and methodical in their preflight preparations. This is especially necessary due to the fact that Falcon Heavy Flight 2 differs dramatically from Falcon Heavy’s demo configuration, degrading the applicability of some aspects of the data gathered during the rocket’s largely successful test flight.

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Most notably, all three first stage boosters will be Block 5 variants on their first flights, whereas Flight 1’s first stage featured two flight-proven Block 2 boosters (B1023 and B1025) and one new Block 3 booster (B1033). Additionally, the center core – B1033 – was lost during a landing anomaly that prevented the booster from reigniting its engine for a landing burn, cutting off another valuable source of data that would have served to better inform engineers on the performance of Falcon Heavy’s complex and previously unproven mechanical stage separation mechanisms.

Official SpaceX renders of Falcon 9 and Falcon Heavy in their Block 5 variants, circa 2019. (SpaceX)

Falcon 9 Block 5 is a fairly radical departure from the Block 2 and 3 variants SpaceX based Falcon Heavy’s initial design on. It’s possible that the rocket’s engineers were able to at least set up that design and manufacturing work on a safe path to forward compatibility, but it’s equally possible that so much work was focused on simply getting the vehicle past its launch debut that compatibility with Falcon 9 Block 4 and 5 was pushed well into the periphery. Considering the fact that it has now been more than a year since Falcon Heavy’s February 6th, 2018 debut, the latter eventuality offers a much better fit. Nevertheless, with a solid 13-14 additional months of redesign and testing complete, it seems that SpaceX is keen to get its super heavy-lift launch vehicle back on the horse, so to speak.

The specific changes made in Falcon 9 Block 4 is unclear aside from a general improvement in Merlin 1D and MVac performance, as well as significant upgrades to Falcon 9’s upper stage, likely focused on US military and NASA requirements for long-coast capabilities on unique mission profiles. Most significantly, Falcon 9 Block 5 transitioned the SpaceX rocket to a radically different primary thrust structure (also known as the octaweb), replacing welded assemblies with bolted assemblies wherever possible. This simultaneously allows for easier repairs and modifications, improves ease of manufacture, and increases the structure’s overall strength, a critical benefit for Falcon Heavy’s heavily-stressed center core. Meanwhile, Falcon 9 Block 5 moved from Full Thrust’s (Block 3/4) maximum 6800 kN (1,530,000 lbf) of thrust to more than 7600 kN (1,710,000 lbf), an increase of roughly 12%. Combined with Block 5’s focus on extreme reusability, SpaceX engineers and technicians likely had to do a huge amount of work to leap from Falcon Heavy Flight 1 to Flight 2.

Falcon Heavy ahead of its inaugural launch. (SpaceX)

Aside from the presence of both Falcon Heavy side boosters, both of which were spotted arriving in Florida by local observers, the first Block 5 Falcon Heavy center core also very likely arrived within the last few months, followed rapidly by can be assumed to be the mission’s fairing and Falcon upper stage. Falcon Heavy’s commercial debut will see the rocket attempt to place communications satellite Arabsat 6A – weighing around 6000 kg (13,200 lb) – into a high-energy geostationary orbit, either direct-to-GEO or a transfer (GTO) variety.

If all goes according to plan, SpaceX will attempt to turn around Falcon Heavy’s Block 5 side boosters (B1052 and B1053) for Falcon Heavy’s third launch – the USAF’s STP-2 mission – as few as 60-80 days later, June 2019. According to NASASpaceflight, STP-2 will fly with a new center core (presumed to be B1057) instead of reusing Arabsat 6A’s well-cooked B1055 booster.

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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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How SpaceX Is raising Raptor’s sea-level thrust while holding engine mass steady

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Credit: SpaceX

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:

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.

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Tesla expands Robotaxi geofence in Houston with an ode to SpaceX merger

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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.

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.

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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.

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Concept rendering of SpaceX Starship landing on the moon via Grok

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.

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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.

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