I crunched some numbers today, and I estimate that troop 445’s balloon achieved 117,723 ft in altitude, and we know that Troop 252’s balloon achieved 114,667 ft! Great work, everyone!
We learned a lot!
We were able to determine that our gear got pretty hot inside of our payload capsule. I am not 100% sure, but I suspect this is the reason that Troop 445’s APRS tracker failed at 98k feet. The temperature was dropping at that point as you can see in the graphs below, but it was still much hotter than ideal. The temperature, reported by a sensor on the APRS Tracker, reported that Troop 252’s capsule reached 41.7C, while Troop 445s capsule reached 62.5C. It was likely hotter in some areas that the sensor was not able to detect.
We believe that there were several reasons that we overheated. First, we added a hand warmer to the payload, which we did to compensate for the very cold temperatures at high altitudes. Secondly, our capsule was very efficient with close to no ventilation or open space at all. Third, we were running 2 GoPro cameras capturing 4k or 1080p footage at up to 48fps, 1 SPOT tracker, and 1 APRS tracker tracking every ~50 seconds in close proximity, which created substantial heat.
Upon further research, we know now that air convection, which our equipment relies on to cool, is much less effective at altitude due to the lack of air to move heat away from the gear. In the future, we will not be adding any hand warmers, and will likely experiment with purposefully venting our capsule to prevent overheating.
We captured incredible footage!
We had 3 of the 4 GoPros shut down prematurely (likely due to heat also), but we were still able to capture really incredible footage. One of the GoPros did not overheat, and was able to capture footage of Troop 445’s capsule landing. This allowed us to closely estimate the final altitude, using the last ascent rate compared with timestamps in the video.
|Takeoff Time:||9:30:10AM PST|
|Total Ascent Time:||2:30:20|
|Total Descent Time:||0:28:24|
|Total Flight Time:||2:58:44|