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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
Elon Musk and James Cameron find middle ground in space and AI despite political differences
Musk responded with some positive words for the director on X.
Avatar director James Cameron has stated that he can still agree with Elon Musk on space exploration and AI safety despite their stark political differences.
In an interview with Puck’s The Town podcast, the liberal director praised Musk’s SpaceX achievements and said higher priorities must unite them, such as space travel and artificial intelligence. Musk responded with some positive words for the director on X.
A longtime mutual respect
Cameron and Musk have bonded over technology for years. As far back as 2011, Cameron told NBC News that “Elon is making very strong strides. I think he’s the likeliest person to step into the shoes of the shuttle program and actually provide human access to low Earth orbit. So… go, Elon.” Cameron was right, as SpaceX would go on to become the dominant force in spaceflight over the years.
Even after Musk’s embrace of conservative politics and his roles as senior advisor and former DOGE head, Cameron refused to cancel his relationship with the CEO. “I can separate a person and their politics from the things that they want to accomplish if they’re aligned with what I think are good goals,” Cameron said. Musk appreciated the director’s comments, stating that “Jim understands physics, which is rare in Hollywood.”
Shared AI warnings
Both men have stated that artificial intelligence could be an existential threat to humanity, though Musk has noted that Tesla’s products such as Optimus could usher in an era of sustainable abundance. Musk recently predicted that money and jobs could become irrelevant with advancing AI, while Cameron warned of a deeper crisis, as noted in a Fox News report.
-->“Because the overall risk of AI in general… is that we lose purpose as people. We lose jobs. We lose a sense of, ‘Well, what are we here for?’” Cameron said. “We are these flawed biological machines, and a computer can be theoretically more precise, more correct, faster, all of those things. And that’s going to be a threshold existential issue.”
He concluded: “I just think it’s important for us as a human civilization to prioritize. We’ve got to make this Earth our spaceship. That’s really what we need to be thinking.”
News
Blue Origin announces Super-Heavy New Glenn 9×4 to Rival SpaceX Starship
The announcement followed the company’s successful NG-2 launch on November 13.
Blue Origin has revealed plans to develop New Glenn 9×4, a “super heavy” rocket designed to deliver 70 metric tons to low-Earth orbit and directly compete with SpaceX’s Starship.
The announcement followed the company’s successful NG-2 launch on November 13, which deployed NASA’s ESCAPADE (Escape and Plasma Acceleration Dynamics Explorers) Mars mission and landed the first stage.
Upgraded engines and reusability
As noted in a Universe Today report, Blue Origin will roll out upgraded BE-4 engines producing 640,000 lbf each, up from 550,000 lbf, starting with NG-3. This should boost the New Glenn rocket’s total first-stage thrust to 4.5 million pounds. Upper-stage BE-3U engines are expected to improve from 320,000 lbf to 400,000 lbf over the next few flights as well.
“These enhancements will immediately benefit customers already manifested on New Glenn to fly to destinations including low-Earth orbit, the Moon, and beyond. Additional vehicle upgrades include a reusable fairing to support increased flight rates, an updated lower-cost tank design, and a higher-performing and reusable thermal protection system to improve turnaround time,” Blue Origin noted.
New Glenn “Super Heavy” 9×4
The super-heavy New Glenn 9×4, with nine BE-4s on the booster, four BE-3Us on the upper stage, will feature an 8.7-meter payload fairing. Blue Origin expects New Glenn 9×4 to be capable of transporting 70 metric tons to LEO, 14 tons to GSO, and 20 tons to trans-lunar injection, as noted by the company in a blog post. This is very impressive, as New Glenn 9×4’s capacity exceeds Falcon Heavy, SpaceX’s largest rocket available to consumers today. Falcon Heavy is capable of carrying up to 64 metric tons to low Earth orbit in a fully expendable configuration.
-->That being said, SpaceX’s Starship’s capacity is extremely impressive. As per SpaceX, Starship is designed to be capable of carrying up to 100-150 metric tonnes to orbit in its fully reusable configuration. At its expendable configuration, Starship’s capacity enters unheard-of territory, with SpaceX stating that the vehicle could transport 250 metric tonnes of cargo.
News
Tesla FSD approved for testing in Nacka, Sweden, though municipality note reveals aggravating detail
Nacka, Sweden, a municipality just a few miles from Stockholm, has given its approval for FSD tests.
Tesla has secured approval for FSD testing in an urban environment in Sweden. As per recent reports from the Tesla community, Nacka, Sweden, a municipality just a few miles from Stockholm, has given its approval for FSD tests.
A look at the municipality’s note regarding FSD’s approval, however, reveals something quite aggravating.
FSD testing approval secured
As per Tesla watcher and longtime shareholder Alexander Kristensen, Nacka is governed by the Moderate Party. The shareholder also shared the municipality’s protocol notes regarding approval for FSD’s tests.
“It is good that Nacka can be a place for test-driving self-driving cars. This is future technology that can both facilitate mobility and make transportation cheaper and more environmentally friendly,” the note read.
The update was received positively by the Tesla community on social media, as it suggests that the electric vehicle maker is making some legitimate headway in releasing FSD into the region. Sweden has been particularly challenging as well, so securing approval in Nacka is a notable milestone for the company’s efforts.
-->Aggravating details
A look at the notes from Nacka shows that FSD’s proposed tests still met some opposition from some officials. But while some critics might typically point to safety issues as their reasons for rejecting FSD, those who opposed the system in Nacka openly cited Tesla’s conflict with trade union IF Metall in their arguments. Fortunately, Nacka officials ultimately decided in Tesla’s favor as the company’s issues with the country’s unions are a completely different matter.
“The left-wing opposition (S, Nackalistan, MP and V) voted no to this, referring to the fact that the applicant company Tesla is involved in a labor market conflict and does not want to sign a collective agreement. We believe that this is not an acceptable reason for the municipality to use its authority to interfere in a labor law conflict.
“Signing a collective agreement is not an obligation, and the company has not committed any crime. The municipality should contribute to technological development and progress, not work against the future,” the note read.
Elon Musk and James Cameron find middle ground in space and AI despite political differences
Blue Origin announces Super-Heavy New Glenn 9×4 to Rival SpaceX Starship
