The amount of gear we needed to research and acquire, as well as the number of other things we had on our plates in the final months before our departure, contributed to planning our launch after we’d hit the road. The biggest factor in this decision though was geography - Ontario is covered in lakes and forests, but we knew we would be spending two weeks in southern Manitoba in July, and that our chances at recovering a landed balloon in sprawling prairie fields would be much better then deep in the forests of central Ontario and Quebec.
I took care of most of the research and procurement. Hobbyists typically launch 600 gram balloons, which can usually carry a modest 0.5-1kg payload to 80,000-100,000ft.
100,000ft (~30,000m) is generally considered the ‘edge’ of space, or ‘near space’, and tends to be the approximate target altitude for hobbyists like us. A few variables affect a balloon trying to achieve a given altitude:
Volume of the balloon
Amount of helium put into the balloon
Weight of payload
You might think that more helium in a balloon would make it go higher, but in reality, the upper altitude limit is defined by the maximum ‘stretched’ capacity of the balloon. As it rises, the lower amount of atmospheric pressure allows the helium to expand. The balloon rises and grows until it reaches maximum size, then pops. For maximum altitude, you actually want as little helium as possible. To allow for maximum growth.
The lower limit of helium in the balloon is a function of the mass you’re trying to lift. More payload = more helium you need to put in to make it float = balloon bursts at a lower altitude. So to try for maximum altitude, you need a light payload and just enough helium to get it rising.
The next factor to consider is wind.
If the balloon was filled with just enough helium to lift, the balloon would be rising really slowly, which would be ok if there was no wind at all. In reality, trying to find a windless day is near impossible, and not made easier by the fact that we were limited to a launch window of only a few days in Manitoba - ideally when my brother and his family were also visiting our parents.
A few days before our launch window, we started checking High Altitude Ballooning flight estimation websites and plotting various potential scenarios. These websites plot probable trajectories based on both surface wind and balloon variables.
As our preferred launch day had predicted winds of about 20 km/hr, we had to expect significant drift, and tried to identify a launch site which would minimize the risk of landing in Lake Winnipeg - or worse - the United States. COVID 19 would make an international recovery mission impossible.
We searched for a potential launch site with the help of Google maps. Criteria included:
Large open field
No nearby airfields
Away from major roads,
Away from gawkers or anyone who might object to the very unusual activity which is launching a big balloon
When we found the large empty (because of COVID) sports complex in Moosomin, Saskatchewan, we knew we had our spot. The flight path estimator plotted a landing within 30 minutes of my parent’s house in Shoal Lake, MB, but we had to drive over an hour to get there.
