We had two recent weather balloon launches in southeastern Washington. On Monday, May 31 we launched a 1200 g balloon at 46° 02.569' N 118° 53.602' W altitude 350 m (1148 ft) at 9:37:52 am. It burst at about 46° 10.366' N 118° 35.677' W at about 10:16:08 - highest recorded altitude was 19035 m (11.83 mi, 62451 ft), about 10 miles NNE of Touchet. It landed at 46° 21.487' N 118° 12.690' W altitude 530 m (1739 ft) at 11:05:51, off Shea road 6 miles NE of Prescott. Flight time was 82 minutes. The recovery team saw it come out of the clouds and land.
Coldest recorded temperature was -44°C (-47°F) at about 33,000 ft. Ascent was generally at about 900 ft/min. After burst, descent rate was about 1600 ft/min then reduced to 400-500 ft/min as the air density increased and the parachute inflated.
Three pods went up with this flight. An APRS pod sent Lat/Long/Alt packets every minute. (aprs.fi, KB9ZNZ-14, 31-May-2010). No packets were received after descending through 37500 ft. We examined the pod a few days later and found both leads from the dipole had come unsoldered. A command pod with a 900 MHz downlink provided Lat/Long/Alt and humidity, pressure, external temperature, internal temperature, battery voltage, x-y-z acceleration, and ascent/descent rate. A data pod with extra sensors was also included that communicated to the command pod over 2.4 GHz.
A camera pod and a “biological experiment” pod were also attached in the sequence. As the balloon was released and the pods were being strung out, a member of the launch crew grabbed the APRS antenna instead of the lines. The plastic covering of the antenna came off, the balloon shot up and the lines to the camera pod broke when the slack was abruptly removed. So the cameras and the cockroaches did not make it off the ground.
On Saturday, June 5 we had our second launch with a 1000 g balloon this time from Arlington, OR at 1:08:40 pm (KB9ZNZ-14, 05-June-2010). We included three pods: command, APRS, and camera. More of the APRS packets were received, but many were missed on the descent (one lead broke). Between altitudes of 27000 and 45000 feet, horizontal velocity was over 100 mph reaching 157 mph. Burst was at approximately 85000 ft, 5 miles NW of Touchet. It landed southeast of Waitsburg. The tracking and recovery team took a position over Waitsburg at launch time and were soon able to receive the 900 MHz signal and APRS packets on a mobile station. Flight time was about 2 hr, 7 min. Distance traveled was 106 miles. Data is still being analyzed.
The camera pod had four action-cam video cameras (Oregon Scientific ATC2K), one downward-, two sideward-, and upward-looking. Video results were mixed. We had good side-view shots at lower altitudes. The upward camera showed the balloon getting bigger but ran out of memory about 10 minutes before burst. The downward camera’s resolution was set too low to get good images. In addition, after burst, the lines were tangle and the downward looking cameras ended up looking upward so we did not get video of the landing that we were hoping for.
Much of the equipment was borrowed from Taylor University in Upland, IN. I attended a workshop there last summer. The equipment can be purchased from StratoStar.net. I teach physics, astronomy, and geography at Walla Walla Community College and I involved my engineering physics and meteorology students in this project. http://union-bulletin.com/stories/2010/06/01/weather-balloon-launch-goes-off-like-rocket