eve: An Open Liquid Rocket Engine

eve: An Open Liquid Rocket Engine

The goal of this project is to develop the first completely open Methalox (LCH4/LOX) liquid rocket engine

eve: An Open Liquid Rocket Engine
Deutsch English Español Français Italiano


In the last decade for software open source philosophy allowed a drastic reduction of costs for shipping and maintaining complex software stacks; most of the biggest projects are indeed open source (e.g. K8s, Linux, OpenStack, VLC) and the Open Source philosophy is used by companies to enrich the conception phase by the contribution of the community, to speed up the feedback loop since it allows direct customers to interact more easily with the developers, to lower the costs since it allows bright developers to get easily in touch with an idea and contribute to it drastically. This vivid environment also brought efficient methodologies of project management to be development and shine and more and more we understood that Open Source is not antagonist to profit (see RHEL).

In contrast to this open and fervent world, Aerospace and Space industry is notoriously risk adverse, especially in Europe, slow and extremely cost ineffective.
Musk has been probably the first to understand that the methodologies, but more than that the sparkling mindset, typical of the software development, could indeed be transpiled to other industry sectors, like the automotive and space sector. The development and management strategies of SpaceX show a high level of affinity with techniques like agile, and continuous development that have been invented for software engineering. We think it is also time for Open.

Getting Involved

If you like what we want to achieve, and you'd love to give us a hand: Register to FOSM > Join the Project and present yourself. We will accept you and give you a link to the discord server of the project we use for chat and meetings 🔥


The aim of this project is to build a Methalox (i.e. LOX + LCH4) LRE (Liquid Rocket Engine) that would be completely open source, in terms of software used to design, hardware schematics and installation procedure. The idea is to create the smallest engine unit that could be used as customization base for companies that need a LRE. The current idea is to build a unit that could be used, as more plug & play as possible, as the engine unit of a last stage of a modern launcher, but also as standardized component for a clustered first stage engine. The idea is to work only on the motor package, without taking into consideration the tank that is a hell of a pain to size and build.


The idea here is to proceed step by step. We did not plan all the steps down: we’re gonna try to apply a rolling wave approach just planning the very next things to do in details and leave the general vision for the medium and long term achievements. In any case I’ll list the general ideas we have at the moment, but first we decided for few principles leading the project:

Fast prototyping: we want to leave the philosophical masturbation at the bare minimum. We want to build some hardware the fastest possible and at the minimum cost

Fail fast, fail often: we want to be able to test several times also the smallest ideas, so the hardware needs to be cheap in order that the “cost per explosion” would be low.

Unified source of truth: documenting is a pain in the ass, so we need to figure out a way to keep all the documentation we produce in one place, easy to search and easy to produce

On the base of these principles we decided the first steps to take:



The first thing we are going to build is basically a burner: a cylindrical combustion chamber without a nozzle. The fuel and oxidizer won’t be cryogenic. What we’re probably going for is gaseous oxygen and LPG (basically Propane). The aim here is to start quickly to build something and make some experience. Basically, the deliverables of this first concept will be:

  • The test bench and feed system: that means all the piping, control and monitoring that we’d like to re-use for future concepts. We’d love to build the testing system in a shipping boat container in a way it would be easily relocatable
  • All the software that we will design to estimate all the things we’ll need
  • Lots of fun!

Technology Stack

Control System

The control system is based on a (potentially series of) ESP32 microcontroller, to which a series of sensors (notably a pressure sensor, a thermocouple and load cell) are connected. The ESP32 then transmits the data wirelessly to a receiving computer, using a MQTT protocol.


For the first prototype, the hardware we're targeting is off-the shelf metallic cylinder / pipes available in general hobby stores.


One of the problems with this project, we know, is going to be the test site. It is a difficult matter, and partnerships will need to be instated if we aim at testing our system in the best conditions possible. In this frame of perspectives, we have some leads about testing sites in Italy and possible ventures that will be interested to host our tests in France.



  1. The first step we are currently actively working on is the so-called cold tests. That is, testing all the pipeline feed lines and the injector in conditions without combustion (with compressed air, for example, or water). This will allow characterizing the hydraulics of the system and also build confidence towards the control system.
  2. Combustion tests to be performed without the nozzle and at ambient temperature, in order to test basic thermal insulation and control system resilience to hard condition.

Later on we will target pressurized hot tests with convergent and convergent / divergent nozzles to characterize the properties of the engine. This tests will likely require a redesign of the system, likely changing the chemicals to allow higher pressure and easier handling of the hydraulics.