Print
Category: 2008
Hits: 5356

Flight 08-C was the annual Aerospace Education Workshop flight for UNO. We had an extensive fog and stratus deck over the region at dawn, which was expected to last much of the morning. With a short flight to the east, we chose the Glenwood (Iowa) High School parking lot as our launch site, and allowed everyone to sleep in a bit as the surface winds were also expected to be light.

Our launch prep went off quickly and we release the balloon with the workshop's BalloonSats attached at 0830 CDT (1330 UTC).  The balloon disappeared almost immediately into the low overcast.

 
 Steam plume from Council Bluffs power plant poking above the low overcast

We headed for Red Oak to a local gas station/convenience store to await burst. Because of the cloud cover, we were unable to treat the teachers to the sight of the balloon visible in the morning sky as it rose. Our 1500g Scientific Sales balloon burst a little early, at 88,534 ft and 0933 CDT (1433 UTC).

Within four minutes after burst, the main payload reported it had lost GPS. This was disappointing, but not too concerning yet as our backup beacon had been very reliable the past few flights. We switched from the primary frequency of 144.36 MHz to the national frequency of 144.39 MHz to listen for N9XTN-12.

We got one report, then nothing. Our hearts sank – this was the first double failure of the APRS beacons. With no DF equipment and minimal DF experience, we were expecting a difficult time of ever locating the payloads. We decided to get everyone back in the vehicles and to start heading for the expected landing area. The main payload was reporting pressure telemetry, so we could deduce an approximate altitude.

As we headed west and north of Red Oak, we made contact with Larry N0BKB who was chasing from the north. We put his group on the backup beacon frequency so we could stay with the main beacon to receive the pressure data and monitor altitude that way. A few minutes later, Larry called to say the backup beacon had come back to life at 21,000 ft. Saved! We switched back to the backup beacon frequency to track it the rest of the way down.

We rolled up on the landing site soon after the touchdown at 1011 CDT (1511 UTC). The landing was in a muddy cow pasture within sight of the road. A couple of us sacrificed our footgear to retrieve the payloads. The balloon remnants, backup beacon, and BalloonSats were a tangled mess – it was somewhat surprising the parachute functioned much at all.

The GPS on the main beacon failed because the DB9 connector separated. This was corrected for future flights by the addition of screw posts for the connector. While not entirely proven, the backup beacon was suspected of having suffered more cold than usual, reducing the internal temperature below where the AA batteries could function that were powering the GPS and TinyTrak3. As it warmed up on descent, the voltage came back up and it began working just in time for recovery.


 

 

Position reports are incomplete due to the payload failures.