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SpaceX’s Starship Raptor Vacuum engine plans laid out by CEO Elon Musk
Elon Musk says that SpaceX Starship engine upgrades are on track to begin static fire tests of a Raptor Vacuum variant as few as a “couple months” from now.
Designed to enable more efficient performance in thin atmosphere or vacuum, Musk admitted that the first version(s) of Raptor Vacuum (RVac) will likely be a compromise between efficiency and speed of development. Nevertheless, the faster SpaceX can prepare Raptor Vacuum for flight, the easier it will be for Starship to begin serious (sub)orbital flight tests.
As it turns out, SpaceX’s first and only official render of Raptor – published in September 2016 – showed the engine’s vacuum-optimized variant. In the years since, CEO Elon Musk has vacillated between keeping the vacuum engines as a central Starship feature and simply replacing them with regular sea level Raptors to expedite the spacecraft’s debut. The 2016 and 2017 vehicles featured a mixture of vacuum and sea-level engines, whereas Musk revealed a vehicle with sea-level engines only in 2018.
Perhaps less than a month after Musk’s September 2018 presentation, the SpaceX CEO made the decision to radically redesign the vehicle – newly christened Starship and Super Heavy – by moving from a carbon composite aerostructure to stainless steel. At first, the seven SL Raptors remained a part of the design, but Musk took to Twitter in 2019 to indicate that SpaceX had changed gears again and had reprioritized Raptor Vacuum development.
This came as a bit of surprise and it should go without saying that there’s a significant chance that Musk/SpaceX will oscillate in the opposite direction once again before Raptor Vacuum is actually ready for flight. This time, though, Musk has sketched out a development schedule and strategy that suggests SpaceX is much more serious this time.
Most notably, Musk claims that the first Raptor Vacuum prototype could be ready for static fire testing just a “couple months” from now, an immensely ambitious schedule for any large liquid rocket engine development program. Nevertheless, Musk did indicate that the “V1.0” Raptor Vacuum design would be significantly compromised and “suboptimal”, an intentional decision to prioritize the engine’s “speed of development”.
Even then, Musk believes that the first variant – featuring a shortened bell nozzle – could still be up to 12% more efficient than sea level Raptors and thus already 70-80% of the way to the physical limit of methane-oxygen rocket efficiency.
On a positive note, shrinking V1.0 Raptor Vacuum’s nozzle a bit from its nominal length will likely mean that SpaceX can static fire fully-integrated engines at its McGregor, TX test facilities, critical for speedy development. If not, the company has experience with alternatives through Merlin Vacuum, which can only be tested on the ground with its lengthy nozzle detached. This method just makes it dramatically harder to optimize a vacuum nozzle design, as full-scale, flight-like testing is nearly impossible if a given vacuum engine can’t be tested on the ground with said nozzle installed.
Vacuum engines need such large and unwieldy nozzles in order to make them as efficient as possible. In a very simplistic sense, a rocket engine nozzle directs the flow of superheated, ultrafast gases in order to squeeze as much momentum transfer as possible out of available propellant. The lower the pressure of the surrounding atmosphere is, the more those gases will expand immediately after leaving the nozzle – giant vacuum nozzles simply try to harness the additional momentum available from that extra expansion. This is why rocket exhausts appear to spread and thin out as launch vehicles reach higher and higher altitudes.
In this sense, the perfect theoretical vacuum nozzle is quite literally infinitely long. The job of vacuum rocket engineers is to find the perfect balance between that impractical theoretical perfection and the limits of real-world materials and dynamics. In theory, SpaceX’s sea-level Raptor engines have already been designed to operate in vacuum conditions, while the engine’s closed-cycle design and regeneratively (i.e. propellant) cooled nozzle should apply well to a vacuum design.
If SpaceX is lucky, there will be few roadblocks in the way of simply lengthening a SL Raptor-style nozzle and calling it a day, in which case it would be impressive but not all that surprising if SpaceX is actually able to begin RVac testing before the end of 2019. Once a rough V1.0 engine is in place, the process of optimizing efficiency can be done slowly and methodically, all while exploiting an unprecedented wealth of data from flight and orbit-tested Raptor Vacuum engines.
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Elon Musk
SpaceX secures win as US labor board drops oversight case
The NLRB confirmed that it no longer has jurisdiction over SpaceX.
SpaceX scored a legal victory after the National Labor Relations Board (NLRB) decided to dismiss a case which accused the company of terminating engineers who were involved in an open letter against founder Elon Musk.
The NLRB confirmed that it no longer has jurisdiction over SpaceX. The update was initially shared by Bloomberg News, which cited a letter about the matter it reportedly reviewed.
In a letter to the former employees’ lawyers, the labor board stated that the affected employees were under the jurisdiction of the National Mediation Board (NMB), not the NLRB. As a result, the labor board stated that it was dismissing the case.
As per Danielle Pierce, a regional director of the agency, “the National Labor Relations Board lacks jurisdiction over the Employer and, therefore, I am dismissing your charge.”
The NMB typically oversees airlines and railroads. The NLRB, on the other hand, covers most private-sector employers, as well as manufacturers such as Boeing.
The former SpaceX engineers have argued that the private space company did not belong under the NMB’s jurisdiction because SpaceX only offers services to “hand-picked customers.”
In an opinion, however, the NMB stated that SpaceX was under its jurisdiction because “space transport includes air travel” to get to outer space. The mediation board also noted that anyone can contact SpaceX to secure its services.
SpaceX had previously challenged the NLRB’s authority in court, arguing that the agency’s structure was unconstitutional. Jennifer Abruzzo, the NLRB general counsel under former United States President Joe Biden, rejected SpaceX’s claims. Following Abruzzo’s termination under the Trump administration, however, SpaceX asked the labor board to reconsider its arguments.
SpaceX is not the only company that has challenged the constitutionality of the NLRB. Since SpaceX filed its legal challenge against the agency in 2024, other high-profile companies have followed suit. These include Amazon, which has filed similar cases that are now pending.
News
Tesla accuses IG Metall member of secretly recording Giga Berlin meeting
The union has denied the electric vehicle maker’s allegations.
Police seized the computer of an IG Metall member at Tesla Giga Berlin on Tuesday amid allegations that a works council meeting was secretly recorded.
The union has denied the electric vehicle maker’s allegations.
In a post on X, Gigafactory Berlin plant manager André Thierig stated that an external union representative from IG Metall attended a works council meeting and allegedly recorded the session. Thierig described the event as “truly beyond words.”
“What has happened today at Giga Berlin is truly beyond words! An external union representative from IG Metall attended a works council meeting. For unknown reasons he recorded the internal meeting and was caught in action! We obviously called police and filed a criminal complaint!” Thierig wrote in his post on X.
Police later confirmed to local news outlet rbb24 that officers did seize a computer belonging to an IG Metall member at the Giga Berlin site on Tuesday afternoon. Tesla stated that employees had contacted authorities after discovering the alleged recording.
IG Metall denied Tesla’s accusations, arguing that its representative did not record the meeting. The union alleged that Tesla’s claim was simply a tactic ahead of upcoming works council elections.
The next works council election at Giga Berlin is scheduled for March 2 to 4, 2026. The facility’s management had confirmed the dates to local news outlets. The official announcement marks the start of the election process and campaign period.
Approximately 11,000 employees are eligible to participate in the vote.
The previous works council election at the plant took place in 2024, and it was triggered by a notable increase in workforce size. Under German labor law, regular works council elections must be held every four years between March 1 and May 31.
Elon Musk
Elon Musk’s xAI plants flag in Bellevue AI hotspot
The lease places xAI’s new office in one of the region’s fastest-growing tech hubs.
Elon Musk’s artificial intelligence company xAI has leased a full floor at Lincoln Square South in downtown Bellevue, WA, as per city permit filings.
The lease places xAI’s new office in one of the region’s fastest-growing tech hubs.
Public records indicate that xAI leased roughly 24,800 square feet in Lincoln Square South. The location was previously occupied by video game company Epic Games. Lincoln Square South is part of the Bellevue Collection, which is owned by Kemper Development Co.
The lease was first referenced in January by commercial real estate firm Broderick Group, which noted that an unnamed tenant had secured the space, as stated in a report from the Puget Sound Business Journal. Later filings identified xAI as the occupant for the space.
xAI has not publicly commented on the lease.
xAI hinted at plans to open an office in the Seattle area back in September, when the startup posted job openings with salaries ranging from $180,000 to $440,000. At the time, the company had narrowed its location search to cities on the Eastside but had not finalized a lease.
xAI’s Bellevue expansion comes as Musk continues consolidating his businesses. Last week, SpaceX acquired xAI in a deal that valued the artificial intelligence startup at $250 billion. SpaceX itself is now valued at roughly $1.25 trillion and is expected to pursue an initial public offering (IPO) later this year.
Musk already has a significant presence in the region through SpaceX, which employs about 2,000 workers locally. That initiative, however, is focused largely on Starlink satellite development.
Bellevue has increasingly become a center for artificial intelligence companies. OpenAI has expanded its local office footprint to nearly 300,000 square feet. Data infrastructure firms such as Crusoe and CoreWeave have also established offices downtown.
SpaceX secures win as US labor board drops oversight case
Tesla accuses IG Metall member of secretly recording Giga Berlin meeting
