eve: The first Open Liquid Rocket Engine

eve: The first Open Liquid Rocket Engine

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

(Projet mené en anglais)


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 thechniques like agile, and continuous development that have been invented for software engineering. We think it is also time for Open.


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 because it generally does not work. 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 al 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!


One of the problems with this project, we know, is going to be the test site. In France, it looks quite difficult to be able to test so the main idea at the moment we are pursuing is to test in Italy (even if I have ideas in the mid term). In particular at my hometown where I know few people at the administration: we are going to task for the free loan of a shepherd house in the same site where Skyward launched its rockets. This house will need to be refurbished, but we believe it might do.


At the moment we did not create a deep roadmap. We highlighted the few activities for the next months that need to be done:

  • Design of the combustion chamber
    • Soldering a plate to an off the shelf pipe vs an already flanged pipe
    • We’re probably going for a simple shower-head injection at the beginning
  • Design of the bench test to be integrated in a shipping container
    • Which board to use? We’d love to use BGC
  • Asking for price quotations of gases including bottle renting and transport
  • Starting the bureaucratic procedure to ask for the free loan of the space in Italy where we’d like to install the test bench
  • Finding a reasonably cheap container to be transported in Italy
  • Setting up the Documentation system based on Lektor + Elastic Solr + Gitlab Runner

We will start a more detailed planning once we have access to Gitlab. The idea, in any case, is to have a first fire test for the summer 2020. summer 2021. 🔥