Developing the most advanced waterrocket.

Electronically controlled waterrocket with Thrust Vectoring, Guidance/Navigation and many more features.

For a general overview, please check out the timeline down below.

To read more about our current engineering efforts visit the Development Blog.

If you are interested in in-depth videos about the project give our Youtube channel a try!

fixed airframe rocket

Pathfinder 1/2

in use: testing

gimbaled airframe poseidon

Pathfinder 2/2


first flying vehicle

Waterrocket 1

concept phase

FAR High Pressure Tests

Over the summer we tested the FAR prototype under higher pressure. For that purpose we bought a 300bar air cylinder and regulator.We conducted the high pressure tests to research thrust and burntime under flying pressures of about 30bar and to check the experimental data against our simulation. Hydrostatic tests At first, to verify that the PVC tanks of the FAR prototype won't explode under the high pressure - the tanks are rated for 10bar, we want to use 30bar - we conducted multiple hydrostatic tests.Hydrostatic - as the name suggests - means we fill the test tank completely with water ...

Machining parts for test tanks

Before we build the flight-ready tanks for the Poseidon Rocket, we're going to manufacture test tanks to see how they're going to perform and hold up to the expected pressures.You can find the concept and design of these tanks in a previous article: Poseidon Tanks: Concept and Design. As discussed previously, the tanks must have a way to connect to valves and fittings. For this purpose we're embedding a machined aluminum adapter into the ends of the tank.So before laminating the tanks, we have to manufacture these adapters. Design This adapter has to transfer the loads of working pressure to ...

Poseidon Tanks: Concept and Design

FAR so far The FAR test platform has tanks made out of PVC. We chose this material because it's quick and easy to build a tank out of, and can sustain a pressure of about 8 bar. Additionally, it is relatively cheap and available. However, these PVC tanks are not flight ready. They weigh almost ten times the flyable weight and cannot sustain the required pressure of about 28 bar. Requirements for the Poseidon tanks Weight The rocket must be light, preferably under 1500g. Our simulations have shown that the rocket at 28bar can lift around 7kg. Leaving some room ...


In the beginning we have to figure out if our target is realistic.
Shouldn't that be the case we need to define a new one. Because the math behind waterrockets is quite complicated, we decided to build the pathfinder test-vehicle FAR (fixed airframe rocket).
As the name suggests, it is fixed to the ground, so not quite a rocket yet. But it is basically an early prototype of the planned Poseidon-Rocket, which is held down by load cells.
This enables us to measure the thrust curve and change in mass over time. With that data we should be able to build a mathematic model and decide whether our goals are feasible or not.

The next logical step after that is the devolpment of a vehicle which verifies our general design of the Poseidon rocket while still being mounted to the ground.
For that purpose we will build the Gimbaled Airframe Poseidon (GAP).
In contrast to FAR, GAP is mounted in a gimbal suspension and will be able to rotate freely around three axes.
We will use this pathfinder vehicle to test our TVC-Mount (Thrust Vectoring Control) and the stability-software which should keep the rocket upright.
We decided to implement this additional phase into the timeline to mature our hard- and software before our first flight attempt.

With the knowledge from FAR and GAP we will develop the Poseidon rocket.
It will feature one thing that GAP lacked: A recovery system. This will be a parachute which serves as an abort throughout the flight as well.
After some ground test of the rocket with focus on the brandnew systems like recovery, Poseidon will be ready for the first flight.

We don't expect the first flight to be a successful one, but we hope that we won't break too much hardware, because we tested the key systems early and intensive.

We don't want to talk about our future plans too much right now, because the way to the first successful flight of Poseidon will be a long and bumpy one. Just one thing to think about: The valve which controls if water exits the rocket or not can be opened and closed during the flight multiple times. This could enable us to perform multiple burns. Random examples for that are a deceleration-burn or a landing burn. But of course these were chosen totally arbitrarily!

Project Poseidon on Youtube