It sounds like quite a few “watched” our flight live on aprs.fi so many of you know some of the story. We only achieved a maximum altitude of 10,352 feet through a 3 hour flight. The flight became a valuable lesson on neutral buoyancy. On to the good news. Our goals were to:
- Perform a successful open field launch. Check!
- Run a series of cameras hacked to shoot astronomical images. Check!
- Capture images of the conjunction of Venus, Jupiter and the Moon. Check!
- Do a night flight with a successful recovery. Check!
We launched on time at 7:04pm from a site in West Aurora with the help of Chas, Mrs. Chas, Arpan and his parents, Rebecca and Mike. Moments after the release we realized things were not going according to plan. We’ve seen a lot of ascents and knew this was way slower than our usual 350meters/min goal. For a time, we thought that the balloon achieved neutral buoyancy at an altitude near 600 meters. As the sun set, the balloon rose slowly. This was probably due to the fact that as the atmosphere cools it becomes more dense. This would mean the density of the helium in the balloon would rise to find a natural level of balance. We were worried that if the condition did not change, our payload could float for hours or even days. Why it began to slowly descend after 2 hours is a different question. Eventually, our payload returned to Earth southwest of Joliet in Channahon, IL just shy of the Des Plaines river. Whew! The payload was visible mere yards from the side of the road in an open field thanks to the flashing lights mounted along the frame.
The stabilized payload frame had five cameras mounted to it. There were four still cameras set to shoot once every 8 seconds and a GoPro video camera. I’m happy to report all the cameras did their job. They were all still operating on recovery. We captured over 3000 images and more than 3 hours of video. We’ll need to process the images but for now I’m posting a relatively unprocessed snapshot from the flight. I’ll put up some selected video and more images as soon as possible.
The challenge now is how to determine lift in an open field launch. While doing the balloon fill we held the balloon down with cloth draped over the balloon to contain it from the effects of the wind. It worked well yet it doesn’t allow checking the lift by our usual method of using an inverted fish scale. Geza has suggested designing a flow meter attachment to the fill tube so we can calculate lift via absolute amount of helium pumped into the balloon.