REXUS-BESPIN

Hi!

My name is Elin Eriksson and I am the head of electrical division. Last week we had a visit from the REXUS/BEXUS program manager Stefan Krämer, SSC, and our mentor from ESA, Hanno Ertel. This visit was due to our "Delta CDR". We had our regular CDR, Critical Design Review, in June together with the other REXUS teams but because of the complete redesign of our experiment we needed to have a another one where we presented the changes. It has been a lot of work to have something presentable to show our visitors but it payed off and they were happy with what we had done. We still have some redesigning to do but we now have a design that we are comfortable and confident about.

 

 

Since we are a bit behind we now have a lot of catching up to do. For us in the electrical division, we have about 2 weeks to both do the testing and to do the PCB designs for 6 boards, which is quite a lot since we are only three people. But in a weird way it feels good to have this pressure and this timeline because that means that we are reaching a new phase. We have been on a CDR level for quite a while now due to the different circumstances so to be able to move over to practical work with the actual components feels really good.

 

With the new design the electrical subsystems has not changed that much. We have changed from three large PCB with multiple systems to a larger quantity of PCBs with less components mounted on them. This is because the new internal structure allows us to have enough room to do this. It will simplify the PCB designs and the debugging if anything malfunctions. We have also added some sensors. We initially did not plan on having sensors in our first version of the experiment, since it was all about the initialisation of different mechanical subsystems, like the balloon and parachute. But now, it is more about the descending phase and how the probe moves with the aerodynamics, which requires some sensors. So the sensors present on the probe will be:

 

- Temperature sensor, to measure the internal temperature of probe.

- Accelerometer, to measure the acceleration throughout the flight. Focusing on parachute activations.

- Pressure sensor, to measure the ambient pressure which will be used for triggering different subsystems at different pressure values (different altitudes).

- Thermocouplers, to measure the temperature at the protective shell during descend and the flare.

- Rate sensor, to measure the attitude of the probe in three axes during descend.

 

We have also included three cameras that will record the parachute deployment and from the side of the probe to see how it tumbles.

 

 

Now it is complete focus on getting everything done in time so we catch up and so that we can show functioning subsystems during the IPR that is during the second week in October. After that we can finally start with the exciting tests that we have planned. Looking forward to it!

 

/Elin Eriksson