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SpaceX Starship passed “cryo proof” test for the first time and here’s what’s next
Elon Musk says a SpaceX Starship prototype has passed a critical “cryo proof” test for the first time, opening the door for the rocket to move on to even bigger tests.
Late on April 26th, SpaceX’s South Texas team (and possibly a console team in California) readied the fourth full-scale Starship prototype (SN4) for its second major test. Known as a cryogenic proof test, it began less than 24 hours after the rocket completed a room-temperature gas pressure test to check for leaks and verify that the pressure vessel was sound. Musk quickly confirmed that Starship SN4 passed through that “ambient proof test” without issue.
For the cryo proof test, room-temperature nitrogen gas was replaced with ultra-cold liquid nitrogen, serving as a chemically neutral (i.e. non-explosive) simulant for Starship’s liquid oxygen and methane propellant. After a few hours of partial loading and offloading cycles meant to ensure that Starship’s valves and propellant supply hardware was working as intended, SpaceX controllers fully filled the rocket with some ~1000 metric tons (2.2 million lb) of liquid nitrogen. Once full, a hydraulic ram setup was activated to exert forces akin to Raptor engines operating at full thrust. After several prior failures, Starship SN4 thus became the first to survive the ordeal and graduate into the next stage of testing.
According to CEO Elon Musk, that next step will be a static fire test with a lone Raptor engine installed. Able to produce at least 200 metric tons of thrust (~450,000 lbf) at full throttle, Raptor is an exceptionally efficient methalox (methane/oxygen) rocket engine designed by SpaceX to power Starship and its Super Heavy booster. Methane and oxygen was chosen in large part because of the relative potential ease of its extraction and refinement on Mars.
Per Musk, that static fire could occur within the next six or so days, meaning that SpaceX will likely install a functional Raptor engine on a full-scale Starship for the first time ever within the next day or two. Before a static fire can be performed, though, another significant test or two will have to be completed.
Known as a wet dress rehearsal (WDR), the first of those tests will be similar to April 26th’s cryo proof but with the neutral liquid nitrogen placed by real liquid oxygen and methane propellant. This is much riskier than the cryo proof in the sense that if a tank failure were to occur or a fire to accidentally start, 1000+ tons of highly-pressurized propellant could easily create a massive explosion and fireball, destroying or damaging much of the surrounding pad equipment. The WDR could potentially be rolled into another Raptor engine test that would verify its preburner performance.


To operate, Raptors first take liquid oxygen and liquid methane into separate parts of the engine and rapidly heat them to turn them into high temperature gas. Those preburners then send that hot gas to separate turbopumps that spin up and allow the engines to keep supplying themselves with large quantities of propellant, followed by the process of actually igniting the engine itself with a complex series of blowtorches.
If the preburner and turbopump spin-up test is successful, SpaceX can then move on to the actual static fire. Featuring a single Raptor engine, Starship SN4 will hopefully become the first full-scale rocket to safely operate a flight-grade engine since SpaceX began full-scale tests in November 2019. If successful, that static fire could pave the way for Starship SN4 to perform a Starhopper-style 150m (500 ft) hop test as early as May 2020 – a hop that would be powered by a single Raptor engine according to Musk.
Starship SN5 will reportedly be the first ship to both have a nosecone installed and three Raptor engines installed if SN4 has a very successful few weeks and that new ship is perhaps just 5-10 days from being fully assembled. In short, things are about to get very busy and very exciting at SpaceX’s South Texas Starship factory and launch pad.
Elon Musk
SpaceX issues statement on Starship V3 Booster 18 anomaly
The incident unfolded during gas-system pressure testing at the company’s Massey facility in Starbase, Texas.
SpaceX has issued an initial statement about Starship Booster 18’s anomaly early Friday. The incident unfolded during gas-system pressure testing at the company’s Massey facility in Starbase, Texas.
SpaceX’s initial comment
As per SpaceX in a post on its official account on social media platform X, Booster 18 was undergoing gas system pressure tests when the anomaly happened. Despite the nature of the incident, the company emphasized that no propellant was loaded, no engines were installed, and personnel were kept at a safe distance from the booster, resulting in zero injuries.
“Booster 18 suffered an anomaly during gas system pressure testing that we were conducting in advance of structural proof testing. No propellant was on the vehicle, and engines were not yet installed. The teams need time to investigate before we are confident of the cause. No one was injured as we maintain a safe distance for personnel during this type of testing. The site remains clear and we are working plans to safely reenter the site,” SpaceX wrote in its post on X.
Incident and aftermath
Livestream footage from LabPadre showed Booster 18’s lower half crumpling around the liquid oxygen tank area at approximately 4:04 a.m. CT. Subsequent images posted by on-site observers revealed extensive deformation across the booster’s lower structure. Needless to say, spaceflight observers have noted that Booster 18 would likely be a complete loss due to its anomaly.
Booster 18 had rolled out only a day earlier and was one of the first vehicles in the Starship V3 program. The V3 series incorporates structural reinforcements and reliability upgrades intended to prepare Starship for rapid-reuse testing and eventual tower-catch operations. Elon Musk has been optimistic about Starship V3, previously noting on X that the spacecraft might be able to complete initial missions to Mars.
Investor's Corner
Tesla analyst maintains $500 PT, says FSD drives better than humans now
The team also met with Tesla leaders for more than an hour to discuss autonomy, chip development, and upcoming deployment plans.
Tesla (NASDAQ:TSLA) received fresh support from Piper Sandler this week after analysts toured the Fremont Factory and tested the company’s latest Full Self-Driving software. The firm reaffirmed its $500 price target, stating that FSD V14 delivered a notably smooth robotaxi demonstration and may already perform at levels comparable to, if not better than, average human drivers.
The team also met with Tesla leaders for more than an hour to discuss autonomy, chip development, and upcoming deployment plans.
Analysts highlight autonomy progress
During more than 75 minutes of focused discussions, analysts reportedly focused on FSD v14’s updates. Piper Sandler’s team pointed to meaningful strides in perception, object handling, and overall ride smoothness during the robotaxi demo.
The visit also included discussions on updates to Tesla’s in-house chip initiatives, its Optimus program, and the growth of the company’s battery storage business. Analysts noted that Tesla continues refining cost structures and capital expenditure expectations, which are key elements in future margin recovery, as noted in a Yahoo Finance report.
Analyst Alexander Potter noted that “we think FSD is a truly impressive product that is (probably) already better at driving than the average American.” This conclusion was strengthened by what he described as a “flawless robotaxi ride to the hotel.”
Street targets diverge on TSLA
While Piper Sandler stands by its $500 target, it is not the highest estimate on the Street. Wedbush, for one, has a $600 per share price target for TSLA stock.
Other institutions have also weighed in on TSLA stock as of late. HSBC reiterated a Reduce rating with a $131 target, citing a gap between earnings fundamentals and the company’s market value. By contrast, TD Cowen maintained a Buy rating and a $509 target, pointing to strong autonomous driving demonstrations in Austin and the pace of software-driven improvements.
Stifel analysts also lifted their price target for Tesla to $508 per share over the company’s ongoing robotaxi and FSD programs.
Elon Musk
SpaceX Starship Version 3 booster crumples in early testing
Photos of the incident’s aftermath suggest that Booster 18 will likely be retired.
SpaceX’s new Starship first-stage booster, Booster 18, suffered major damage early Friday during its first round of testing in Starbase, Texas, just one day after rolling out of the factory.
Based on videos of the incident, the lower section of the rocket booster appeared to crumple during a pressurization test. Photos of the incident’s aftermath suggest that Booster 18 will likely be retired.
Booster test failure
SpaceX began structural and propellant-system verification tests on Booster 18 Thursday night at the Massey’s Test Site, only a few miles from Starbase’s production facilities, as noted in an Ars Technica report. At 4:04 a.m. CT on Friday, a livestream from LabPadre Space captured the booster’s lower half experiencing a sudden destructive event around its liquid oxygen tank section. Post-incident images, shared on X by @StarshipGazer, showed notable deformation in the booster’s lower structure.
Neither SpaceX nor Elon Musk had commented as of Friday morning, but the vehicle’s condition suggests it is likely a complete loss. This is quite unfortunate, as Booster 18 is already part of the Starship V3 program, which includes design fixes and upgrades intended to improve reliability. While SpaceX maintains a rather rapid Starship production line in Starbase, Booster 18 was generally expected to validate the improvements implemented in the V3 program.
Tight deadlines
SpaceX needs Starship boosters and upper stages to begin demonstrating rapid reuse, tower catches, and early operational Starlink missions over the next two years. More critically, NASA’s Artemis program depends on an on-orbit refueling test in the second half of 2026, a requirement for the vehicle’s expected crewed lunar landing around 2028.
While SpaceX is known for diagnosing failures quickly and returning to testing at unmatched speed, losing the newest-generation booster at the very start of its campaign highlights the immense challenge involved in scaling Starship into a reliable, high-cadence launch system. SpaceX, however, is known for getting things done quickly, so it would not be a surprise if the company manages to figure out what happened to Booster 18 in the near future.