This mission will use a military surplus ML-541A/AM balloon, further refining our estimate of that envelope's burst diameter and characteristics. It will include a Peach3 tracker and an 808 #16 camera, which should provide better resolution than the previous launch. We will add some fins to the payload container, hoping to stabilize it in flight for better camera imagery.
The tracker had an undetected issue with the Low Pass Filter on the antenna. We lost contact with the balloon at 5,000 feet. The flight flew to completion and appears to have exceeded our altitude predictions. The payload landed in a field in Freeville, NY, about 12 miles past the anticipated landing area and was returned to us by the farm owner there, 11 days later.
|Balloon||ML-541A/AM military surplus balloon, readily available on ebay|
|Payload||Peach3 Tracker, 808 #16 Micro camera|
|Payload container||Foam box|
|Max Payoad Weight||150g|
|Flight Time||Under 180 min|
|Recovery||Payload free fall|
|Tracking||Peach3 HAB tracker|
|Telemetry||GPS and temperature data.|
|Tracker + Counterpoise||19|
|Tracker Battery - (1) L92 AAA Ultimate Lithium||8|
|#16 808 Camera w/SanDisk 16G SDHC I, Class 4||19|
|Camera Battery - (2) L92 AAA Ultimate Lithium||16|
|Balloon attachment (Final string and tape)||12|
|Total (goal: 1550)||1360|
|ML-541A/AM military surplus balloon||$40|
|Helium or Hydrogen (80 cu ft cylinder)||$66|
|Mini camera & SD card||$58|
|Balloon Mass||1200g Kaymont|
|Target Ascent Rate||4.8 m/s|
|Descent Rate||10.0 m/s|
|Start Location||Holley, New York|
|Ascent Rate||5.26 m/s|
|Neck Lift||1018 g|
|Launch Volume||76.3 cu ft|
|Flight Range||139.1 km|
|Flight Time||104 min|
Using volume of a sphere for 76.3 cu ft
We called it 16' 6 3/8“ circumference.
Expected pounds of gas to use:
PSI = volume / .0265 PSI = 76.3 / .0265 PSI = 2879 PSI drop in tank.
|Burst Altitude||25,952m||27,909m (est)||27,910|
|Ascent Rate||5.26 m/s||5.26 m/s (assumed)||5.26|
|Time to burst||01:22:00||01:27:12||01:28:00|
|Descent Rate||10 m/s||9.34 m/s||9.34 m/s|
|Time to descend (predictor)||00:22:00||00:49:47||00:24:00|
|Time to descend (actual)||00:43:15||00:49:47||00:49:48|
|Flight Range||139.1 km||163.88 km||unknown|
Third column represents a revised prediction assuming 5.8m burst diameter (vs 5.3 assumed prior to launch). This seemed to match the flight times and landing location pretty well.
The payload was secured to the balloon via strings piercing the foam box and looping underneath. At burst, the strings on one side of the payload box tore right through the foam, ripping the end off the box.
In future missions, we should use some kind of reinforcement along with the string to protect the foam box.
The foam box as made somewhat wider than necessary to try and reduce the spinning of the payload. This worked well. Adding longer bars sticking out the sides might add further stabilization.
No data available.
The camera worked flawlessly, capturing the entirety of the flight. Total battery life with two AAA L92 ultimate lithiums was 02:55:35.
Landed in a field. Recovered by a farmer who contacted us based on the name tag on the payload.