HIGH-ALTITUDE BALLOONING 101
LIFTING GAS
HELIUM
We use helium as our lifting gas in the balloon. We still prefer helium instead of hydrogen for two reasons. First, although hydrogen can indeed be safely used for high-altitude ballooning operations, it still poses a big enough safety risk due to its flammable properties that we prefer not to use it for any launches we do with K-12 students. Second, even though the price of helium has skyrocketed in recent years, we are still able to obtain it at relatively affordable prices through the University of Wyoming.
For each launch, we acquire two large, high-pressure helium cylinders (or “tanks”). The tanks contain either 200 cubic ft (K-size) or 300 cubic ft (T-size) of compressed helium. Each tank weighs well over 100 pounds! Having two tanks is necessary for many of our launches. It usually takes 300–400 cubic feet of helium to fill the balloon so that it has enough free lift to carry the payload train upward at our desired ascent rate (about 5–6 m/s). One K-size tank is usually not enough to completely inflate the balloon, even for our lightest payloads. One T-size tank is sometimes sufficient when flying lighter payload trains, but we always bring two tanks just in case we need extra helium. The second tank also acts as a backup in case we have an accidental balloon failure while we are filling it.
ACQUIRING HELIUM
We almost always provide the helium for the launch. However, the host school or K-12 group may offer to provide or purchase their own helium if they wish. Although we welcome such offers, this is certainly not a requirement. Indeed, our annual budget accounts for the helium we purchase for these launches. As of 2024, many helium suppliers in Wyoming have stopped accepting new customers, and the cost to rent large helium tanks can be quite high ($300+ per tank). Fortunately, thanks to an arrangement the university has with one of these suppliers, we still have access to a reliable supply of helium at a somewhat reduced rate.
We have worked with multiple helium suppliers over the years. Two of these suppliers, Airgas and Norco, both have many branch locations across Wyoming and surrounding states. We’ve also sourced helium from Rocky Mountain Air Solutions, formerly U.S. Welding.
DELIVERY AND SAFETY
In the past, we usually asked the helium suppliers to deliver the tanks directly to the school several days prior to the launch. This approach, while perhaps a little more convenient, was not always very reliable. These days, we source helium from our supplier on campus and bring the tanks with us to each launch. This removes the headache of having to coordinate with an out-of-town supplier. It also removes the potential concern from teachers and schools regarding helium tank storage.
WHAT EDUCATORS NEED TO KNOW
We will bring the helium with us on launch day. However, if the teacher/educator, or the host school, would like to purchase or provide their own helium for the launch, please let us know as soon as possible!