Flight Recap for EOSS-184

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Student Outreach Payload Data


KC0UUO-11 Maiden Flight

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by Doug Gentges, N0IX

I sat down this morning with the data from EOSS-184.

First, the Outreach payload. We had a very successful flight. One anomaly occurred in flight, and that is that the GPS did not report position above 12km. Fortunately, it continued to log time, and I was able to transfer the GPS data from the KC0UUO-11 payload based on the time stamps.

Individual Sensors: Pressure/Inside Temperature (Bosch BMP085): The pressure data tracks very well with the GPS altitude up to about 15km. Above that the barometer starts to trend low. Lowest reported pressure was 18.18hPa. Converting that to altitude using the standard atmosphere and a nominal SLP gives 23,704m, which is somewhat lower than the GPS reading of 26,512m. The Pressure sensor has an onboard temperature sensor, which recorded a low of -24.4C during descent. This indicates that there was most likely some cold air intrusion into the payload.

Outside Temperature/Relative Humidity (Sensirion SHT15): The relative humidity values look reasonable up to burst, although I'm not exactly sure what to expect here. During descent, the RH spikes, but then returns to more reasonable values once on the ground. Like the Barometer, this part also has an onboard temperature sensor, which was left exposed to the outside environment. It recorded a low of -27.69C

UV/Light sensors: I need to perform a little more analysis on the data from these sensors. The output is very noisy, so I'm going to try to go back through with some data averaging to see if I can get a better looking result.

The enclosure did suffer some damage, most likely when being pulled out of the tree. It may need some minor repair before flying again. Also, the O3 sensor arrived in the mail, and integrating that sensor will require some modifications to the enclosure

For KC0UUO-11 As you are most likely aware, there were very few packets logged on the ground from the payload while in flight. From what is known so far, it appears to either be a transmit power or antenna issue. More investigation needs to be done. The payload was transmitting when recovered, and did log good GPS data for the entire flight. The batteries performed nominally Pre-flight voltage was 7.21v, post flight is 6.84v. I'll need to do some investigation to see how long they would have lasted, or if they can be used on multiple flights.

Mechanically, the payload is in good shape. A small nylon screw used to hold the Tiny Track 4 and GPS board in place had the head snapped off. This may have happened in-flight, but more likely when it was dropped from the tree during recovery. The kydex frame came through fine.

Attached are two files. The first is a CSV file of outreach payload data. You should be able to import this into your spreadsheet of choice for data graphing.

The second is a .kmz file of the GPS data from KC0UUO

webmaster note: This payload was designed and built by Doug Gentges. It collects a variety of data that should offer an excellent data source for flying in the stratosphere for students.