SpaceForest has proposed a sounding rocket as a technology demonstrator for the WP.2.4 work package as well as for the whole Aeronautics domain of the Programme. Two subsystems, developed by the consortium partners will be mounted on board the specially designed internal frame of the rocket:
- MTL – Multilink Telemetry Logger – manufactured by Thales Alenia Space Spain for space rockets. This device consist of two parts:
– logger – stores data from wireless sensors,
– telemetry module – sends the data to the ground station: directly, and indirectly – via satellite,
- RFTM – Radio Frequency Trajectory Monitoring – developed by University of Technology in Gdańsk, will monitor the flight parameters and send the landing spot information to the ground station.
The main task of the rocket is to test the WSN, developed by SpaceForest, in actual flight conditions. The wireless nodes will be mounted on the inner scaffold of the rocket, allowing for the outside fuselage removal. This allows for trouble-free tests in the laboratory environment, and also for direct access to all parts of the on-board equipment.
Because radio wave transparency is important for the WSN operation, the rocket was designed to have as little metal components as possible.
The demonstrator rocket consists of following components:
1. Inner scaffold – main structure of the rocket.
2. Nose Cone – contains tracking and telemetry systems.
3. Optional Guidance System – for flight trajectory correction.
4. Recovery System – necessary to land safely.
5. Payload Bay – space for MTL and RFTM subsystems.
6. Tanks – composite oxidiser tanks.
7. Main Valve and Ignition System – engine ignition system.
8. Combustion Chamber and stabilising fins– main part of the engine.
1. Inner scaffold
Internal structure of the rocket is made of composite (fibre glass/epoxy) longitudinal tubes, and a set of polyurethane, sandwich-type composite discs, forming a “ladder” frame. This structure holds all the elements of the rocket together, so that outside “shell” can be taken off, without dismantling the whole launcher.
2. Nose cone
Nose cone is made of epoxy-fibreglass composite transparent for RF signals. Under the nosecone cover, few systems are located:
- Radiolocation system – our independent tracking system developed specially for research rockets. The main functionality is sending localization coordinates from a rocket to the ground terminal. More details you can find here
- GPS/GSM tracker – additional, cheap, commercial tracking system,
- RawGPS – GPS signal logger for flight trajectory determination.
3. Guidance system
Guidance system is a prototype and still under development in cooperation with Gdańsk University of Technology. The sensor circuitry is based on a three axis accelerometer and a MEMS gyro. Four small aerodynamic fins are actuated by electric servomechanisms. Data from the guidance system will also be transferred by WSN. Guidance is an optional part of the DEWI project.
System was successfully tested using aerodynamic tunnel (Warsaw University of Technology) within a shortened version of the rocket (without the tank and payload section). Tests will lead to the final version of drivers, allowing for elimination of rocket’s rotation and keeping the planned flight path.
4. Recovery system
Consists of two parachutes (drogue and main) and their deployment system. The “brain” of the unit is a flight computer (Arecorder) developed by Arek Paliński in cooperation with SpaceForest. Arecorder uses data from accelerometers and a pressure sensor to determine characteristic points of the flight and trigger parachute deployments.
At the apogee, pneumatic piston rejects the nose cone and releases a small parachute. It allows for a fast, stable descent (about 15m/s) until the main parachute opens. This results in landing closer to the launch site. The main parachute decreases the descend rate to about 5m/s and is released at a chosen altitude above the ground for a safe landing.
The whole system was flight-tested on board a specially designed big rocket model.
5. Payload bay – contains MTL, RFTM, or any other required payload
6. Oxidiser tanks
Oxidiser tanks are made of carbon fibre/epoxy composite, with chemically inert liners. Tanks compartment will also contain the oxidiser feed line temperature and pressure sensors as a part of the WSN.
7. Main valve and ignition system
Engine actuation system consists of the main valve, controlled by electric servomechanisms and an ignition circuit. The main valve is a key element of the hybrid rocket engine. It controls the flow of the oxidiser (N2O) from the tanks into the combustion chamber and allows engine to start and cut off. It is very important to open a valve at the appropriate time after firing the initiating charge, so both valve and ignition are remotely controlled from the ground station. The main valve has an angle sensor which monitors the current angle of valve opening. This indicator will also be used as a WSN sensor.
The system consists of four elements:
Remote Control Unit (RCU) – sending commands from ground station to Valve & Ignition Control Unit placed in the rocket.
Main valve with actuators – two electric servomechanisms for controlling the main valve, additionally equipped in angle sensor
Valve & Ignition Control Unit (VICU) – responsible for wireless communication with RCU module, control of main valve opening and initialization of ignition process. This modules is placed inside the rocket.
Wrap-around patch array antenna for VICU – VICU antenna is specially designed for this rocket demonstrator.
When wrapped (e.g. on a main fuel tank), the antenna has an omnidirectional radiation pattern. Under the antenna, a RF-isolated area is created, in which electronic components of VICU can be placed.
8. Combustion chamber and stabilising fins
The main part of the propulsion system, containing a modified paraffin wax fuel. The combustion chamber is held in a reinforced structure which is also the mounting place for the stabilizing fins. The engine bed will also be a place with temperature monitored via WSN. For more details about the combustion chamber click here