[3][1] Archimedes was presented on December 2, 2021, in a webcast by Rocket Lab CEO Peter Beck[4] 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.
[5] 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.
"[6] In the September 21st, 2022 Investor Day Presentation, the engine design had changed to an oxidizer-rich staged combustion cycle.
[citation needed] Archimedes is presented as a highly reusable liquid-propellant engine using methane and liquid oxygen in an oxidizer-rich staged combustion cycle.
The rationale for the cycle change from the original gas generator was that they could not get the performance they needed through all the throttle points that a reusable rocket needs, without pushing the turbine temperature and other factors beyond their preset limits.