Archimedes is a liquid-fuel rocket engine burning liquid oxygen and liquid methane in an oxidizer-rich staged combustion cycle. It is designed by aerospace company Rocket Lab for its Neutron rocket.
History
Archimedes was presented on December 2, 2021, in a webcast by Rocket Lab CEO Peter Beck as a fully reusable, gas generator engine using liquid oxygen (LOX) and methane as propellant, a departure from the company's previous Rutherford, which is electrically pump fed. He then stated that it had a thrust of 1 MN and 320 seconds of specific impulse. The same day, the Neutron page on Rocket Lab's website was updated specifying the thrust of the nine Archimedes engines used on the first stage as 5960 kN at sea level and a maximum thrust of 7530 kN and the upper stage's single vacuum optimized Archimedes at 1110 kN. It was expected to have its first hot-fire test during May 2024. In an interview published on the CNBC website, Beck stated that Archimedes would be manufactured in New Zealand and its very simple design had "all the things you want when you have to build an engine that can be reused over and over again."
In the September 21st, 2022 Investor Day Presentation, the engine design had changed to an oxidizer-rich staged combustion cycle. The presentation stated that the sea level version would have a maximum thrust of 730 kN with a specific impulse of 329 seconds and would be able to throttle to 50% of maximum thrust.