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SpaceX CEO Elon Musk: Starship prototype to have 3 Raptors and “mirror finish”

SpaceX CEO Elon Musk visited the South Texas site where Starship's first prototype is being built on December 23rd. (Elon Musk)

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Taking to Twitter once more to reveal additional information about SpaceX’s radically changing BFR/Starship prototype program, CEO Elon Musk has made an unexpected visit to the company’s South Texas BFR testing facilities to oversee rapid progress with a low-fidelity hop test prototype of the orbital Starship spacecraft.

Included in a handful of replies that followed the tweeted image, Musk described some of the key advantages of a stainless steel Starship – including mirror-like thermal reflectivity for hot reentries and a “usable” strength-to-mass ratio superior to carbon fiber – as well as features of prototype cousin.

While the CEO did imply on Saturday that the Mars-focused Raptor engine had been what he described as “radically redesigned”, Musk’s statement that the Starship hopper will feature three Raptor engines does at least set a lower bound for the ship’s maximum gross takeoff weight when the time comes for it to take flight.

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While the suggestion that Raptor’s turbopumps (basically fuel pumps) would need at least 100,000 HP per engine seems to indicate that the flight design’s thrust has been appreciably uprated, a past figure of ~2000 kN (450,000 lbf) per engine suggests that Starship V0.1 could weigh as much as an entire Falcon 9 Block 5 rocket (~1.2 million pounds, 550,000 kg) and still having a solid 80-100% of Falcon 9’s liftoff thrust. Put simply, the rocket that appears to be coming together in the boonies of South Texas could rival almost any other liquid fuel rocket booster in service, while still being the testbed for BFR’s upper stage alone.

While it’s ambiguous if several additional comments applied to the Starship prototype, the final product, or both, Musk also indicated that some of the biggest benefits of a shift away from carbon composites to stainless steel would be relative ease with which the material handles extreme heating. Thanks to the fact that stainless steel can ultimately be polished to mirror-like levels of reflectivity and that mirrors are some of the most efficient reflectors of thermal energy (heat), shiny and unpainted steel would ultimately perform far better than carbon composites and could end up requiring “much less” heat shielding for the same performance.

 

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Perhaps most unintuitive is the fact that steel can apparently beat carbon composites when it comes to usable strength-to-weight ratios at supercool temperatures. According to Musk, steel also performs “vastly better” at high temperatures and appreciably better at room temperatures. A comment made on Saturday may lend additional credence to what seems at face value to contradict basic material intuition –  at least some of the stainless steel SpaceX is examing would be a special (presumably SpaceX-engineered) alloy that has undergone what is known as cryogenic treatment, in which metals are subjected to extremely cold conditions to create some seriously unintuitive properties. Ultimately, cold-formed/worked or cryo-treated steel can be dramatically lighter and more wear-resistant than traditional hot-rolled steel.

Combined with advanced new alloys and a uniquely strong handle on working with supercool propellant (likely transferable to cold-forming steel), SpaceX and CEO Elon Musk could have a true breakthrough on their hands, especially if it turns out that a great deal of deep thought, analysis, and refinement fed into these “radical” design changes. With Starship Alpha’s hop tests potentially beginning as early as March 2019, we won’t have long to wait to find out.


For prompt updates, on-the-ground perspectives, and unique glimpses of SpaceX’s rocket recovery fleet check out our brand new LaunchPad and LandingZone newsletters!

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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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Elon Musk reveals SpaceX’s target for Starship’s 10th launch

Elon Musk has revealed SpaceX’s target timeline for the next Starship launch, which will be the tenth in program history.

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Credit: SpaceX

Elon Musk has revealed SpaceX’s target timeline for the next Starship launch, which will be the tenth in program history.

Musk says SpaceX is aiming for a timeline of roughly three weeks from now, which would come about ten weeks after the previous launch.

Coincidentally, it would bring the two launches 69 days apart, and if you know anything about Elon Musk, that would be an ideal timeline between two launches.

SpaceX is coming off a test flight in which it lost both the Super Heavy Booster and the Upper Stage in the previous launch. The Super Heavy Booster was lost six minutes and sixteen seconds into the flight, while SpaceX lost communication with the Ship at 46 minutes and 48 seconds.

Musk is aiming for the tenth test flight to take place in early August, he revealed on X:

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This will be SpaceX’s fourth test flight of the Starship program in 2025, with each of the previous three flights bringing varying results.

IFT-7 in January brought SpaceX its second successful catch of the Super Heavy Booster in the chopstick arms of the launch tower. The ship was lost after exploding during its ascent over the Turks and Caicos Islands.

IFT-8 was on March 6, and SpaceX caught the booster once again, but the Upper Stage was once again lost.

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The most recent flight, IFT-9, took place on May 27 and featured the first reused Super Heavy Booster. However, both the Booster and Upper Stage were lost.

The Federal Aviation Administration (FAA) hit SpaceX with a mishap investigation for Flight 9 on May 30.

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SpaceX’s Crew-11 mission targets July 31 launch amid tight ISS schedule

The flight will lift off from Launch Complex 39A at Kennedy Space Center in Florida.

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(Credit: SpaceX)

NASA and SpaceX are targeting July 31 for the launch of Crew-11, the next crewed mission to the International Space Station (ISS). The flight will lift off from Launch Complex 39A at Kennedy Space Center in Florida, using the Crew Dragon Endeavour and a Falcon 9 booster.

Crew Dragon Endeavour returns

Crew-11 will be the sixth flight for Endeavour, making it SpaceX’s most experienced crew vehicle to date. According to SpaceX’s director of Dragon mission management, Sarah Walker, Endeavour has already carried 18 astronauts representing eight countries since its first mission with NASA’s Bob Behnken and Doug Hurley in 2020, as noted in an MSN report.

“This Dragon spacecraft has successfully flown 18 crew members representing eight countries to space already, starting with (NASA astronauts) Bob (Behnken) and Doug (Hurley) in 2020, when it returned human spaceflight capabilities to the United States for the first time since the shuttle retired in July of 2011,” Walker said.

For this mission, Endeavour will debut SpaceX’s upgraded drogue 3.1 parachutes, designed to further enhance reentry safety. The parachutes are part of SpaceX’s ongoing improvements to its human-rated spacecraft, and Crew-11 will serve as their first operational test.

The Falcon 9 booster supporting this launch is core B1094, which has launched in two previous Starlink missions, as well as the private Ax-4 mission on June 25, as noted in a Space.com report.

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The four-members of Crew-11 are NASA astronauts Zena Cardman and Mike Fincke, as well as Japan’s Kimiya Yui and Russia’s Oleg Platonov.

Tight launch timing

Crew-11 is slated to arrive at the ISS just as NASA coordinates a sequence of missions, including the departure of Crew-10 and the arrival of SpaceX’s CRS-33 mission. NASA’s Bill Spetch emphasized the need for careful planning amid limited launch resources, noting the importance of maintaining station altitude and resupply cadence.

“Providing multiple methods for us to maintain the station altitude is critically important as we continue to operate and get the most use out of our limited launch resources that we do have. We’re really looking forward to demonstrating that capability with (CRS-33) showing up after we get through the Crew-11 and Crew-10 handover,” Spetch stated.

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SpaceX launches Ax-4 mission to the ISS with international crew

The SpaceX Falcon 9 launched Axiom’s Ax-4 mission to ISS. Ax-4 crew will conduct 60+ science experiments during a 14-day stay on the ISS.

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(Credit: SpaceX)

SpaceX launched the Falcon 9 rocket kickstarting Axiom Space’s Ax-4 mission to the International Space Station (ISS). Axiom’s Ax-4 mission is led by a historic international crew and lifted off from Kennedy Space Center’s Launch Complex 39A at 2:31 a.m. ET on June 25, 2025.

The Ax-4 crew is set to dock with the ISS around 7 a.m. ET on Thursday, June 26, 2025. Axiom Space, a Houston-based commercial space company, coordinated the mission with SpaceX for transportation and NASA for ISS access, with support from the European Space Agency and the astronauts’ governments.

The Ax-4 mission marks a milestone in global space collaboration. The Ax-4 crew, commanded by U.S. astronaut Peggy Whitson, includes Shubhanshu Shukla from India as the pilot, alongside mission specialists Sławosz Uznański-Wiśniewski from Poland and Tibor Kapu from Hungary.

“The trip marks the return to human spaceflight for those countries — their first government-sponsored flights in more than 40 years,” Axiom noted.

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Shukla’s participation aligns with India’s Gaganyaan program planned for 2027. He is the first Indian astronaut to visit the ISS since Rakesh Sharma in 1984.

Axiom’s Ax-4 mission marks SpaceX’s 18th human spaceflight. The mission employs a Crew Dragon capsule atop a Falcon 9 rocket, designed with a launch escape system and “two-fault tolerant” for enhanced safety. The Axiom mission faced a few delays due to weather, a Falcon 9 leak, and an ISS Zvezda module leak investigation by NASA and Roscosmos before the recent successful launch.

As the crew prepares to execute its scientific objectives, SpaceX’s Ax-4 mission paves the way for a new era of inclusive space research, inspiring future generations and solidifying collaborative ties in the cosmos. During the Ax-4 crew’s 14-day stay in the ISS, the astronauts will conduct nearly 60 experiments.

“We’ll be conducting research that spans biology, material, and physical sciences as well as technology demonstrations,” said Whitson. “We’ll also be engaging with students around the world, sharing our experience and inspiring the next generation of explorers.”

SpaceX’s Ax-4 mission highlights Axiom’s role in advancing commercial spaceflight and fostering international partnerships. The mission strengthens global space exploration efforts by enabling historic spaceflight returns for India, Poland, and Hungary.

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