Electronics in the nosecone of Stratos III

Stratos III is getting ready for the launch. In order to get this 8.2 meters tall rocket to perform an attempt to break the student altitude record, it needs to be controlled. This is done by the Flight Computer, which acquires data of all sensors and provides telemetry. This Flight Computer fills the biggest part of the nosecone of Stratos III.

This part of the rocket is designed and made by the electronics team of DARE and consists of multiple custom-designed printed circuit boards (PCBs). It gathers the data of all sensors and actuators, which is processed by microcontrollers from NXP. These microcontrollers are very reliable and are the industry standard.

All PCBs need to talk to each other, for which we need cable harnessing in between. The harsh conditions during the flight require very decent cables. For Stratos III, these cables are made at Capable which produces them with a very high quality.

The Flight Computer.

These PCBs are programmed to send down flight data and even a live video through the antennas. The nosecone has two antennas, one for the video live stream and one for the data of the rocket. These antennas are located in the top part of the nosecone, inside a big piece of foam. This ensures the antennas to be located at the right position. The foam is radio transparent to make sure that the signals from the antenna can get through.

Both antennas are QFH (quadrifilar helix) antennas, as shown on the picture. These antennas consist of four metal wires, folded in a cosine shape. The special ability of these antennas is that they can transmit the signal with a very wide reflection pattern. This means that the antenna can be received at all time, independent of the position of the rocket.

The antenna for the video livestream.

Besides the Flight Computer, the nosecone of Stratos III also contains a payload of NLR (Netherlands Aerospace Centre). This is their avionics box which records flight data such as the rocket’s location and position using gyroscopes and Global Navigation Satellite Systems (GNSS) like Galileo and GPS. The data of the payload will be stored in the Fight Computer and a part of it will be directly sent back to the ground station.

by Simon Verkleij