While Rocket Lab continues to launch the Electron rocket and pursue partial reusability, they also have been ramping up work on the next-generation Neutron launch vehicle. Most recently this came in the form of the first full Archimedes engine static fire. This new and more powerful engine will provide thrust for both the first and second stages of Neutron.
With this step complete, Rocket Lab is getting closer to creating actual flight hardware and starting full-scale tests of the rocket. Here I will go more in-depth into the recent hot fire, other progress on Neutron, what to expect in the coming months, and more.
Archimedes Hot-Fire
Starting back in early July, Rocket Lab CEO Peter Beck tweeted saying, “Successful pre burner ignition and run. We will probably play for a week or so tuning propellant timings before we open the main valves for a full stage run. These engine cycles are very sensitive to start up transients and timings so correct characterisation of all the transients and operating points is important to understand.” This included an image of the engine on the test stand completing its startup. After this, a few weeks passed by until earlier this month on the 6th when he tweeted again, “Archimedes has been breathing fire! Started at low power and now cranking it up.” While they didn’t release any video of the test, both he and Rocket Lab later confirmed that the engine got up to 102% power and was in flight configuration.
In an official statement, they said, “Archimedes performed well and ticked off several key test objectives, including reaching 102% power, anchoring the engine’s design ahead of Neutron’s first flight scheduled for mid-2025 – a schedule that would make Neutron the fastest a commercially developed medium-class launch vehicle has been brought to market.” Arguably even more significantly they also said, “With the hot fire complete and full qualification campaign now underway, the Rocket Lab team is moving into full production of flight engines.” This is quite a big deal and a massive milestone toward the eventual first launch of this rocket. Each Neutron vehicle needs 10 Archimedes engines in total, 9 on the first stage and a single vacuum-optimized engine on the second stage. The sooner Rocket Lab can begin producing these engines consistently, the faster pre-launch testing and eventual launches will take place. When it comes to new rockets the engine is often one of the most complex yet important pieces, especially when they are necessary for reusability and a propulsive landing like in this instance.
After the static fire, Peter Beck was quoted saying, “Hot firing Archimedes is a major development milestone for Neutron and our team has done it on an accelerated timeline. Taking a new staged combustion liquid rocket engine from cleansheet design to hot fire in just a couple of years is industry-leading stuff. We’ve been consistently impressed with the performance of Archimedes in test, including with this hot fire, so with this critical milestone completed, we move into production of flight engines confidently and begin to close out the qualification test campaign in parallel to really hone performance for launch next year. From the day we started designing Archimedes we focused on delivering a flight engine, rather than an early-stage prototype destined for multiple reworks and adjustments, so it’s gratifying to see this strategy bear fruit” he said.
Focusing more on the engine itself the Archimedes engine is an oxidizer-rich staged combustion cycle engine that is designed to carry up to 13,000 kilograms of payload to space on Neutron. Capable of producing up to 165,000 (733 kilonewtons) pounds of thrust per engine, Archimedes intends to operate at lower stress levels than other rocket engines to enable rapid and reliable reusability. The combined thrust of nine Archimedes engines for Neutron’s first stage is designed to reach 1,450,000 lbf total. Archimedes uses a cryogenic propellant mix of liquid oxygen and LNG to enable higher reusability and performance, and many of its critical components are 3D printed including Archimedes’ turbo pump housings, pre-burner and main chamber components, valve housings, and engine structural components. Altogether this is hoping to create an engine that is both powerful and can be reused with minimal refurbishment between missions.
In the future Neutron’s first stage along with its fairings is trying to land back on the ground after deploying the second stage. This means those 9 first-stage engines will return on a successful mission. In the coming months, we should expect to see production for this engine ramp up and even more engine testing.
Neutron Construction
Besides the news on Neutron’s engine, Rocket Lab also confirmed that the planned maiden flight date is mid-2025. In other words, they are trying to get a fully flight-capable Neutron vehicle ready in around less than a year. While ambitious, they have been making a lot of progress, even beyond just the engines. For example, last month Peter Beck tweeted saying, “The engine development often steals the limelight but it is just one element of a huge system. Everyone forgets just how much infrastructure and concrete needs to go into the ground to make a high-cadence rocket program successful. Not as exciting as fire but just as fundamental.” This included an image of the new water tower that was just constructed at Pad 0D. The 283 ft / 86 m tall tower has a 200,000-gallon capacity to feed Neutron’s deluge system which protects the pad from the intense heat and vibration from the Archimedes engines on lift-off.
In addition, they confirmed that concrete is flowing fast on the launch mount, where a dedicated new pad for Neutron is designed to enable rapid turnaround between missions. A few images from Rocket Lab showcase this progress in action. They also confirmed that just a 5-minute drive from the pad, the Neutron Integration Facility is under construction. It’s from this facility that completed Neutron rockets will roll out to the pad before taking to the skies.
Lastly, only a few days ago on the 12th Rocket Lab tweeted saying, “How it started v How it’s going. Flight hardware is in production for Neutron’s reusable fairing. Humans for scale. This included images of the initial mockup and now actual construction on the vehicle.
They also released more footage on the machine meant to produce Neutron at a rapid pace. Here they were quoted saying, “When you’re making the world’s largest carbon composite rocket, you need the world’s largest carbon composite rocket-building machine of its kind. Say hello to the newest addition in our automated production line: our 75-ton, custom-designed AFP machine that will produce all of Neutron’s largest composite structures and save 150,000+ manufacturing hours in Neutron’s production process.”
AFP stands for Automated Fiber Placement, and Rocket Lab describes it as an industrial process that massively accelerates the laying down of carbon fiber onto a mold to build large carbon composite structures. In the past, we had seen clips of this machine in use but nothing as in-depth as what was recently shared. It seems that at this point the company is ramping up Neutron related work in practically all aspects.
In terms of overall progress, Rocket Lab keeps up to date a timeline of Neutron milestones leading to an eventual maiden flight. Right now thanks to the recent static fire, 5 of these steps are now marked as complete. These include the stage 2 build, structural and cryogenic testing, the Archimedes engine build, testing of the avionics and communication devices, and finally the static fire. The next 3 milestones are all marked as under progress and feature the flight mechanism test program, the stage 1 build, and completing the launch complex. When those three steps are completed, the plan is to hot-fire both stages, integrate the vehicle, finish a final wet dress rehearsal, and launch toward the middle of 2025.
Even with quite a bit of work left, Rocket Lab seems confident. In relation to Archimedes, after the first engine was completed Peter Beck said, “Having a completed Archimedes engine on the test stand is an inflection point in Neutron’s development program. Now we’ve entered the home stretch where we breathe fire and refine the engine in preparation for first flight. Often with engine development plans there can be a rush to get a minimum viable product to the stand, after which you have to spend years in redesign and iterative testing to get the performance you need, let alone being able to reproduce it reliably on a large production scale. What we’ve taken to the test stand is very close to a flight-like engine, and with all of our production infrastructure stood up alongside the engine’s development, we’re in a prime position to be able to make quick iterations to Archimedes for a rapid development and qualification campaign. We took the time to not only bring a mature design to the stand that has been thoroughly tested at the component level, but to also stand up the experienced team, manufacturing line, and test facilities required to support the long-term production of Archimedes. This approach has ultimately pushed the first flight to mid-2025 at the earliest, but it’s an approach we believe will deliver the frequent flight rates the market needs quickly after flight one. Designing a brand-new rocket engine to meet the market demand for frequent and reliable launch is complex feat, but it’s something we’ve successfully done before, having launched more than 470 Rutherford engines to space. We look forward to repeating this success with Archimedes” he said.
They reported that production of subsequent Archimedes engines are continuing in parallel with the ongoing test campaign, with long-lead 3D printed components already manufactured and undergoing checkouts and analysis ahead of integration and engine full assembly at Rocket Lab’s Engine Development Complex in Long Beach, California. In other words, Rocket Lab is truly making a push toward this vehicle’s maiden flight.
Conclusion
Earlier this month Rocket Lab completed the first Archimedes engine static fire. At the same time, they are working on Neutron stage production, Launch Complex 3, and other maiden flight-related developments. We will have to wait and see how it progresses and the impact it has on the space industry.