Neutron’s Archimedes Engine Is Making Impressive Progress
Neutron is a very unique partially reusable launch vehicle attempting to address the growing industry need and demand for constellation launch services. While the rocket has important features such as reusable fairings, and a new primary material, the engine development of Archimedes is arguably the most valuable. Neutron’s future launch capability and opportunity for both quick and cost effective reuse depend on it.
While we have seen initial hardware tests and learned about Rocket Lab’s plan, yesterday we got a sneak peek at an engine in the manufacturing process. This comes in addition to work at the company’s newly acquired test stand. All of which will have a significant impact on the results of these engines and whether or not they facilitate Neutron’s ambitious goals.
This being said, rocket engine development is by no means easy and comes with a host of complications and challenges. Here I will go more in-depth into Rocket Lab’s current plan for Neutron, the work they have completed so far, what to expect in the coming months, and more.
Neutron Engine
For months now, Rocket Lab has been working to manufacture and test the hardware necessary to put together a next generation rocket engine. Yesterday the company tweeted saying, “It’s full methane-and-LOX steam ahead for Neutron’s engines in California. Full scale Archimedes components incl. injectors & combustion chambers are being 3D printed from our giant machines in RLHQ, putting our extensive additive manufacturing experience to use on new engines.” This included an image of the engine nozzle and main structure being manufactured.
In the tweet, they mentioned that this work is happening in California where the company has a few facilities. In the future, this work is expected to move toward Virginia where the main Neutron production process and facility will be located. As this site gets built up, it’s likely that Rocket Lab wanted to start engine production and testing as soon as possible and would rather use existing facilities than wait for Virginia to be ready.
Either way the company has options, especially with the recent bid of approximately $16.1 million for Virgin Orbit’s 144,000+ square foot headquarters and manufacturing complex also located in California.
Looking at the Archimedes Engine schedule, we should expect a few big tests very soon based on what Rocket Lab has said. During the Investor Day Presentation last year, they expected to start preburner testing in 2022, hopefully starting full engine testing at Stennis before 2023 ends, and hoped to be able to launch in 2024. So far they have been just a few months behind this goal. Early this year in January Rocket Lab completed a big milestone in the development of Archimedes. Here they tested engine ignition on dev hardware. At the time they mentioned that the next step would be hot firing hardware with full propellant flow rates to verify injector performance. While the goal was to start full engine testing this year, it’s possible with 6 months left however the most realistic timeframe is around early next year.
Looking at the engine itself, Archimedes is a highly reusable liquid-propellant engine using methane and liquid oxygen in an oxidizer-rich staged combustion cycle. There are both sea-level and vacuum variants. The engine is mostly 3D printed, with some of the biggest 3D printers in the world.
When originally announced, Peter Beck explained that they are trying to make the most reliable and reusable engine which is the reason for the slightly lower isp. He stressed that this engine is going to be reused again and again and the less stress it goes through the better. The engine also changed from a gas generator cycle to oxidizer rich closed cycle. As the company worked through the content of operations and did all the power balances, they found very high turbine temperatures, not enough margin, and overall the need for a lot of compromises. Specifically, the oxidizer rich closed cycle provides a higher specific impulse than gas generator, open expander, or tap-off cycles, without the thrust limits or added complexity. Gas generator cycles are limited in capability and not suited to the deep throttling required for multiple re-lights in orbit, and for landing the first stage. ORSC engines operate at relatively low temperatures and pressures, eliminating the stress and thermal strain experienced by gas generator engines. This improves engine life and reusability, while leaving headroom to increase performance.
Testing Infrastructure
Starting in September of last year, Rocket Lab selected NASA’s Stennis Space Center in Mississippi as the location of its engine test facility for its reusable rocket, Neutron. Just weeks later NASA’s Stennis Space Center and Rocket Lab USA cut the ribbon on a new agreement for the aerospace company to locate its engine test complex. Since then, we have seen work on the site and actual dev hardware tests of the Archimedes engine.
With the new agreement, the A-3 Test Stand and about 24 surrounding acres at Stennis will be incorporated into the Archimedes Test Complex. Rocket Lab will have exclusive access to use and develop the A-3 Test Stand area, including associated propellant barge docks and buildings. The initial 10-year agreement includes an option to extend an additional 10 years. The Mississippi Development Authority is providing assistance for Rocket Lab to develop the new site and to relocate and install needed equipment. To put the speed of this process in perspective, Peter Beck commented, “It was only a few weeks ago when we announced Stennis as the location of our Archimedes Test Complex and we’re already fast at work to get the site up and running to deliver Neutron. Thanks to our partnership with NASA and the state of Mississippi, we can begin to develop the existing infrastructure and test stand at Stennis to fast-track Neutron’s first launch. We look forward to breathing fire in the great state of Mississippi.”
Focusing on the importance of this facility related to Neutron, the Archimedes Test Complex will be located within the larger A Test Complex at Stennis Space Center across a 1 million square foot area. The Archimedes Test Complex will include exclusive use and development of existing industrial NASA infrastructure and the Center’s A-3 Test Stand. Rocket Lab has also secured a capital investment incentive from the Mississippi Development Authority to further develop the facilities and infrastructure at Stennis for Neutron. By expanding Stennis Space Center to include the Archimedes Test Complex, Rocket Lab is expected to create dozens of new jobs and make significant capital investments in the state of Mississippi.
Due to the size and power of this engine and the speed at which Rocket Lab is hoping to develop and test it, this site is very important for their future. Rocket Lab expects to begin construction in the Archimedes Test Complex at Stennis to build two newly built horizontal engine test cells for single engine testing. As testing of the Archimedes engine gets underway, Rocket Lab also envisions building an additional test cell with the ability to test individual engine components.
Peter Beck also pointed out that “Before rockets flew to the Moon, they first had to go through Mississippi, and as we build a new rocket to reshape space access once again, Stennis is a fitting location for Neutron. Creating a test complex from scratch to the scale and complexity needed to test and develop Archimedes would have had an inconceivably long lead time, so the fact that we’ve secured Stennis and can leverage its existing infrastructure and test stand puts us on the fast-track to Neutron’s first launch. The icing on the cake is having fantastic partners like NASA and the state of Mississippi behind us to bring innovative rocketry, economic development, and new jobs to the Gulf Coast” he said.
While the engine itself is obviously important, deals and access to large buildings and test stands like this are what determine the timeline and overall success of a rocket engine. Without it, Rocket Lab would need to spend additional money and time creating or finding a good location and stand.
This doesn’t even include the Neutron Production Complex which will be home to a rocket production, assembly, and integration facility, as well as a dedicated launch pad for the Neutron rocket located on the southern end of Wallops Island. The estimated 250,000 square foot state-of-the-art complex will be constructed on a 28-acre site adjacent to the Wallops Island Flight Facility and will include a Launch Control Center, Rocket Lab’s fifth global operations center for launch activities and on-orbit operations. To support rapid production of the Neutron rocket, current plans for the complex include automated fiber placement robotic production systems capable of laying up meters of Neutron’s new, specially formulated carbon composite structures in minutes.
Considering the size and location of this facility, we can expect to see a lot of future engine work here as it becomes operational.
Conclusion
Rocket Lab is continuing to work on the Archimedes engine with a full static fire in its sights. This would be a significant milestone and a very good sign for the Neutron program as a whole. We will have to wait and see how it progresses and the impact it has on the space industry.
