APRS and Ballooning

At the "Fire in the Sky 05" rocketry activity at Mansfield, WA over the Memorial Day weekend, there were about a hundred amateur rocket enthusiasts shooting off a variety of model rockets, from the smaller Estes rockets, to ones with diameters about 6". It was quite a show. Also at the event Sunday morning was a high altitude balloon experiment headed by Paul Verhage of Boise. Paul was working with Mansfield school students on packages for the event.

Paul, Robert Nech, me, and about 5-6 others of the balloon launch crew met at Mansfield HS Sunday morning at 0500. Yes, 0500. We did a quick checkout of the trackers (2, just like NASA), and set off for the launch point determined by a computer modeling application because we wanted to recover back at the rocket launch area. The launch point was about 12 miles nw of the school. At 0603 hrs the balloon was on its way up. We all headed back to the rocket launch area and monitored the balloon's rise on my UI-View laptop, and visually through several star scopes the rocketeers had brought along to watch the evening sky. We easily watched the balloon during its ascent and slightly west of us. At 82k feet the balloon burst. I was watching it with eyeballs when all of a sudden it appeared to disappear. Paul estimated the balloon's diameter at about 25ft when it burst.

We tracked the descent by APRS. Based on the parachute size and weight of the package, Paul estimated the recovery point and we plotted that on the APRS screen. About 6 cars of the recovery team drove to the area where we anticipated the package would land. When we arrived at the planned LZ, we estimated the package would continue further southwest based on current descent. We arrived at the new location and easily watched the parachute and package descending over us and landing in an open field about 1/4 further west of us. Paul, Robert and several others walked out and recovered the package and we headed back to the school to examine the two student projects. A data recorder captured internal temperatures during the flight, ranging to 0 degrees on the ascent, and about -20 degrees on the descent. Fun stuff.

Balloon ready for launch 0602. At 0603 the balloon was airborne

From launch site to burst ground track was 9 miles. Burst was at 87602 feet over Hwy 172, 7.3 miles west of Mansfield, on course 193 degrees from the launch site. The computer calculated the likely landing site another 4.5 miles along course 193, also over Hwy 172. The actual landing site was further to the west 2.5 miles, in an open field (icon KD4STH-11). Total flight time was just over two hours.