Most weather balloons are launched from the same location every day, so researchers in those locations often have a building of some sort that they use for filling the balloon before moving it outside. The building provides shelter from the wind so the balloon is not flailing around during the fill. Since we are moving around and launching from different locations most days, it’s not practical to haul a building from site to site. Inspired by a youtube video we saw from NOAA’s National Severe Storms Laboratory where they were launching balloons in all sorts of foul-weather situations using a fabric tube, we sewed our own balloon launcher tube. It’s basically a cylinder of fabric held together with a Velcro “ripcord” and straps that attach to weights on the ground to keep it from blowing away. The empty balloon is unfurled inside the tube and then filled with helium. Once the payload is attached and all the tracking and logging components are working, a runner pulls the ripcord to release the balloon and voila, the flight string is lifted off the ground and the AirCore is underway.
We pay attention to the wind direction when we lay out the launcher tube and flight string, so when the balloon is first rising it should fly over the person who is holding up the AirCore, the last piece of equipment on the flight string. We once launched in winds of approximately 20 mph! By the time we actually launched, the wind had shifted a bit and it ended up being an exciting test of Jack’s speed. He sprinted along with the AirCore in hand so it wouldn’t drag across the ground as the balloon was initially traveling farther in the horizontal direction instead of the vertical.
