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Relativity’s first 3D-printed rocket aims to debut a new rocket fuel
Relativity can almost taste the vacuum of space. A substantial amount of work remains, but the startup continues to defy expectations with its relentless and methodical push towards the first orbital launch of a 3D-printed rocket.
Founded in 2015, the Los Angeles-based aerospace company has taken its few years of obligatory delays in stride while pursuing a 2020 debut for its (relatively) small Terran 1 rocket. In a world with dozens of serious rocket startups, missing one’s initial launch target is practically a rite of passage – the path to orbit is never as straight and bump-free as the highway on-ramps that are often promised in pitch decks. Relativity Space, however, is no average rocket startup.
Save for SpaceX, which operates in a league of its own, no other private rocket startup has come close to matching the $1.3 billion Relativity has raised to develop Terran 1 and the much larger Terran R. More importantly, in a recent interview with Aviation Week, CEO Tim Ellis (a former Blue Origin engineer) revealed that the company could be “weeks away” from the first launch of Terran 1, a rocket that is 85% 3D-printed by mass and could simultaneously debut a new kind of rocket fuel.

Once fully assembled, Terran 1 – weighing around 9.3 tons (~20,500 lb) empty and measuring 33.5 meters (110 ft) tall – will be the largest metal 3D-printed object in the history of the technology. From that perspective, it’s hardly surprising that Relativity Space is a few years behind schedule. In fact, it’s odd that the startup isn’t more delayed, and it’s even more impressive that Terran 1’s first launch campaign has gone as smoothly as it has.
Slow, Smooth and Fast
Terran 1 Flight 1’s booster stage and upper stage both arrived at the company’s leased Cape Canaveral Space Force Station LC-16 pad sometime in May 2022. Terran 1’s first stage came directly from the California factory. The second stage (S2), however, first shipped to a Mississippi test stand a few months prior and, on its first try, completed a full-duration multi-minute static fire test known as a mission duty cycle (MDC) – about as close as it’s possible to get to replicating orbital upper stage operations on the ground. The flawless MDC was preceded by a number of simpler precursor tests, of course, but the rocket performed more or less as expected throughout the entire qualification program. If Terran’s second stage ignites again, it’ll be at the edge of space.

Since June, the critical path for Terran 1’s launch debut has thus been qualifying the first finished Terran booster. Rather than modify its Mississippi test facilities, Relativity decided to temporarily modify its heavily upgraded LC-16 pad to support booster qualification testing. Thanks to the heroic work of a shockingly small team of five people, the pad was ready to kick off testing as soon as the Terran 1 booster arrived in Florida. Even more surprisingly, senior manager Lorenzo Locante says that LC-16 – practically a new pad after Relativity’s extensive modifications – has “performed perfectly” during every booster qualification test attempted thus far.
That testing has included pneumatic proofing (an ambient-temperature gas pressure test), possible cryogenic proof tests, multiple rounds of propellant loading, preignition testing of its nine Aeon engines, and multiple spin-start tests (the last step before static fire testing) with the same engines. Given that LC-16 and Terran 1 must handle cryogenic oxidizer (liquid oxygen) and cryogenic fuel (liquid methane), which can easily create a flammable and bomb-like mixture of gases from even the smallest of leaks, it’s difficult to emphasize just how difficult it is to ensure that a complex launch pad and rocket perform nominally during their first joint testing.


According to engineers onsite during a private Teslarati tour of Relativity’s Florida launch facilities, Terran 1 S1’s next goal is to fully ignite its Aeon engines. After one or more successful static fires, the booster will be integrated with the upper stage and nosecone for a final full-duration static fire test that will also double as a full wet dress rehearsal (WDR). Testing the fully-integrated Terran 1 rocket will only be possible once LC-16’s full strongback and launch mount (also known as a transporter/erector) is completed, but that final piece of the puzzle should be ready any day now.
De Terra Ad Astra
The coming weeks will likely be some of the company’s riskiest and most difficult yet. If the rocket and LC-16 continue to operate as smoothly as they have been, however, there’s a nonzero chance that Terran 1 could beat the likes of SpaceX (Starship), Blue Origin (New Glenn), and the United Launch Alliance (Vulcan Centaur) to the punch to become the first methane and oxygen-fueled rocket in history to attempt an orbital launch.*
*While SpaceX’s Starship is technically the first large-scale suborbital methalox rocket to attempt (and complete) a launch, there has never been an orbital methalox launch attempt.
Capable of carrying up to 1.25 tons (~2750 lb) to low Earth orbit for as little as $12 million, Terran 1 also has a shot at becoming the first new privately-developed 1-ton-class rocket of any kind to successfully reach orbit. On that front, though, Relativity is in a neck-and-neck race with Firefly Aerospace and ABL Space, both of which intend to launch similarly-sized rockets at some point in the next few months. It’s never been less clear who will cross the finish line first but one would be hard-pressed to count Relativity out.

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Elon Musk makes a key Tesla Optimus detail official
“Since we are naming the singular, we will also name the plural, so Optimi it is,” Musk wrote on X.
Tesla CEO Elon Musk just made a key detail about Optimus official. In a post on X, the CEO clarified some key wording about Optimus, which should help the media and the public become more familiar with the humanoid robot.
Elon Musk makes Optimus’ plural term official
Elon Musk posted a number of Optimus-related posts on X this weekend. On Saturday, he stated that Optimus would be the Von Neumann probe, a machine that could eventually be capable of replicating itself. This capability, it seems, would be the key to Tesla achieving Elon Musk’s ambitious Optimus production targets.
Amidst the conversations about Optimus on X, a user of the social media platform asked the CEO what the plural term for the humanoid robot will be. As per Musk, Tesla will be setting the plural term for Optimus since the company also decided on the robot’s singular term. “Since we are naming the singular, we will also name the plural, so Optimi it is,” Musk wrote in his reply on X.
This makes it official. For media outlets such as Teslarati, numerous Optimus bots are now called Optimi. It rolls off the tongue pretty well, too.
Optimi will be a common sight worldwide
While Musk’s comment may seem pretty mundane to some, it is actually very important. Optimus is intended to be Tesla’s highest volume product, with the CEO estimating that the humanoid robot could eventually see annual production rates in the hundreds of millions, perhaps even more. Since Optimi will be a very common sight worldwide, it is good that people can now get used to terms describing the humanoid robot.
During the Tesla 2025 Annual Shareholder Meeting, Musk stated that the humanoid robot will see “the fastest production ramp of any product of any large complex manufactured product ever,” starting with a one-million-Optimi-per-year production line at the Fremont Factory. Giga Texas would get an even bigger Optimus production line, which should be capable of producing tens of millions of Optimi per year.
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Tesla is improving Giga Berlin’s free “Giga Train” service for employees
With this initiative, Tesla aims to boost the number of Gigafactory Berlin employees commuting by rail while keeping the shuttle free for all riders.
Tesla will expand its factory shuttle service in Germany beginning January 4, adding direct rail trips from Berlin Ostbahnhof to Giga Berlin-Brandenburg in Grünheide.
With this initiative, Tesla aims to boost the number of Gigafactory Berlin employees commuting by rail while keeping the shuttle free for all riders.
New shuttle route
As noted in a report from rbb24, the updated service, which will start January 4, will run between the Berlin Ostbahnhof East Station and the Erkner Station at the Gigafactory Berlin complex. Tesla stated that the timetable mirrors shift changes for the facility’s employees, and similar to before, the service will be completely free. The train will offer six direct trips per day as well.
“The service includes six daily trips, which also cover our shift times. The trains will run between Berlin Ostbahnhof (with a stop at Ostkreuz) and Erkner station to the Gigafactory,” Tesla Germany stated.
Even with construction continuing at Fangschleuse and Köpenick stations, the company said the route has been optimized to maintain a predictable 35-minute travel time. The update follows earlier phases of Tesla’s “Giga Train” program, which initially connected Erkner to the factory grounds before expanding to Berlin-Lichtenberg.
Tesla pushes for majority rail commuting
Tesla began production at Grünheide in March 2022, and the factory’s workforce has since grown to around 11,500 employees, with an estimated 60% commuting from Berlin. The facility produces the Model Y, Tesla’s best-selling vehicle, for both Germany and other territories.
The company has repeatedly emphasized its goal of having more than half its staff use public transportation rather than cars, positioning the shuttle as a key part of that initiative. In keeping with the factory’s sustainability focus, Tesla continues to allow even non-employees to ride the shuttle free of charge, making it a broader mobility option for the area.
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Tesla Model 3 and Model Y dominate China’s real-world efficiency tests
The Tesla Model 3 posted 20.8 kWh/100 km while the Model Y followed closely at 21.8 kWh/100 km.
Tesla’s Model 3 and Model Y once again led the field in a new real-world energy-consumption test conducted by China’s Autohome, outperforming numerous rival electric vehicles in controlled conditions.
The results, which placed both Teslas in the top two spots, prompted Xiaomi CEO Lei Jun to acknowledge Tesla’s efficiency advantage while noting that his company’s vehicles will continue refining its own models to close the gap.
Tesla secures top efficiency results
Autohome’s evaluation placed all vehicles under identical conditions, such as a full 375-kg load, cabin temperature fixed at 24°C on automatic climate control, and a steady cruising speed of 120 km/h. In this environment, the Tesla Model 3 posted 20.8 kWh/100 km while the Model Y followed closely at 21.8 kWh/100 km, as noted in a Sina News report.
These figures positioned Tesla’s vehicles firmly at the top of the ranking and highlighted their continued leadership in long-range efficiency. The test also highlighted how drivetrain optimization, software management, and aerodynamic profiles remain key differentiators in high-speed, cold-weather scenarios where many electric cars struggle to maintain low consumption.

Xiaomi’s Lei Jun pledges to continue learning from Tesla
Following the results, Xiaomi CEO Lei Jun noted that the Xiaomi SU7 actually performed well overall but naturally consumed more energy due to its larger C-segment footprint and higher specification. He reiterated that factors such as size and weight contributed to the difference in real-world consumption compared to Tesla. Still, the executive noted that Xiaomi will continue to learn from the veteran EV maker.
“The Xiaomi SU7’s energy consumption performance is also very good; you can take a closer look. The fact that its test results are weaker than Tesla’s is partly due to objective reasons: the Xiaomi SU7 is a C-segment car, larger and with higher specifications, making it heavier and naturally increasing energy consumption. Of course, we will continue to learn from Tesla and further optimize its energy consumption performance!” Lei Jun wrote in a post on Weibo.
Lei Jun has repeatedly described Tesla as the global benchmark for EV efficiency, previously stating that Xiaomi may require three to five years to match its leadership. He has also been very supportive of FSD, even testing the system in the United States.
