HIGH-ALTITUDE BALLOONS

What is a high-altitude balloon?
A high-altitude balloon is a large balloon filled with a lighter-than-air gas, such as helium or hydrogen, that carries a package or series of packages (called the payload) high into the atmosphere. The payload often includes various electronics like cameras or atmospheric sensors. These sensors measure things like temperature, humidity, air pressure, and wind speed at different heights above the ground. Many other types of sensors could also be included in the payload. The data that is collected can be analyzed to help us better understand what is happening in the atmosphere.

What is the difference between a high-altitude balloon and a weather balloon?
A high-altitude balloon is a broad term used to describe any large balloon that carries a payload high into the atmosphere. A weather balloon is a specific type of high-altitude balloon that only carries meteorological sensors, such as a radiosonde.

What is the balloon made of?
The balloons that we use are made out of a thin, stretchy material called latex.

How big is the balloon?
When we launch, our balloons are usually about 6–8 feet wide. As they rise high into the atmosphere, they expand to more than 25 feet wide (larger than a small school bus!) before finally popping.

How much does the balloon cost?
Most of the balloons we regularly use cost anywhere from $75 to $150 each, depending on size. Very large latex balloons can cost upwards of $300–400, although we rarely use those.

How high can the balloon ascend?
The weather balloons we use usually reach heights of over 90,000 feet (17 miles) above sea level, where the air pressure is about 100 times lower than it is at sea level. This is well into the stratosphere, the next layer of the atmosphere above us. Currently, the highest balloon we have launched in Wyoming went up to over 107,000 feet. However, this is well below the world record of 173,000 feet set in 2002 in Japan.

How far can the balloon travel?
This depends mostly on how strong the winds are high in the atmosphere in a region called the jet stream. During the summer, the winds in the jet stream are usually pretty weak, so a weather balloon might land only 20–30 miles away, perhaps even closer. In winter, the jet stream can sometimes be very strong and carry balloons as far as 100 miles away or more!

How long does a high-altitude balloon flight last?
From launch to land, our balloon flights are usually a little more than 2 hours long. It typically takes about 90 minutes for the balloon to reach its maximum altitude and burst. After that, it takes another 30–45 minutes for the payload to fall back to earth.

Why does the balloon pop?
Before we can answer this, we must think about air pressure. The air pressure at any location is essentially the weight of all the air that is pushing down from above that spot. At the ground, the entire the atmosphere is pushing down from above so the air pressure is highest. High in the atmosphere closer to space, there is much less atmosphere above, so the total weight of the air above is less and the air pressure is lower.

When the balloon is at the ground, the pressure from the helium pushing outward against the inside of the balloon is balanced with the atmospheric air pressure pushing back on the outside of the balloon. This balance is what gives the balloon its size. As the balloon goes up through the atmosphere, the amount of helium inside stays the same (unless there is a leak). However, the air pressure on the outside of the balloon from the atmosphere gradually gets weaker. In other words, the outside air is pushing back less and less against the helium, so the balloon must expand to reach a balance.

Eventually, the balloon reaches the limit to how much it can expand and it pops (or bursts, as we like to say). Once this happens, the payload no longer has anything to carry it upward and therefore begins to fall back to earth.

Can we see the balloon pop high in the atmosphere?
If there are no clouds overhead and the sky is blue (i.e., not hazy or smoky), it is possible to see the balloon with the naked eye when it pops! The balloon looks like a tiny white speck that is nearly impossible to see unless you are actually looking for it. The best chances of seeing the balloon in these situations is when the balloon is away from the sun. If you can keep your eyes locked on the balloon, it will suddenly disappear when it pops. We have only witnessed it popping a couple times, but it was quite incredible!

Why can’t we touch the balloon with our bare hands?
We have oils in our skin that help keep our skin moist. Our hands are especially oily. If someone were to touch the balloon’s thin, stretchy latex with their bare hands, they would get a little bit of that oil on the balloon. This is no big deal at first, but as the balloon rises through a part of the atmosphere where the temperatures fall below freezing, the oil on the balloon may freeze and prevent that part of the balloon from expanding any further. The rest of the balloon, however, will continue to expand, causing the balloon to eventually take on an irregular shape. This could cause the balloon to burst earlier, and at a lower altitude, than it is supposed to. To prevent this, we try to always wear gloves on our hands whenever we have to touch the balloon.

OUR PAYLOADS

What payloads do we send up with the balloon?
The payload items that we always send up with our balloons are: (1) a parachute, (2) a flight computer called the SatCom, (3) a suite of HD video cameras, and (4) a backup GPS unit. We also give students and teachers the opportunity to send their own payload packages and experiments up with the balloon as well. Starting in 2023, we also began sending up a small radiosonde package with all of our payloads. All of these payload items together are considered the balloon payload. The payload items are connected to each other and to the balloon with a system of strings and nylon harnesses.

Can you tell me more about the SatCom?
The SatCom, or Satellite Communication device, is a flight computer that is equipped with a suite of sensors. The GPS sensor can determine the SatCom’s latitude, longitude, and altitude above sea level. The meteorological sensors can measure temperature, air pressure, and humidity. An onboard accelerometer and gyroscope can measure acceleration and spin rate, respectively. The SatCom can also calculate the wind speed and wind direction based on changes in its GPS position over time. The SatCom is designed and maintained by Stratostar, an education company also focused on high-altitude ballooning and K-12 science outreach.

During flight, data from the various sensors are transmitted to the Iridium satellite network once per minute and immediately send to the internet. This allows us to track the balloon’s location and monitor the onboard data in real time as the payload ascends and descends through the atmosphere! You can check out the SatCom data feed from a previous launch in Douglas, WY, by clicking here.

Can you tell me more about the meteorological sensors on the SatCom?
At this time we do not have specific details on the sensors or how they function. It has been our experience that the air pressure sensor provides the most accurate and consistent measurements. The temperature sensor measurements are often at least 25°F too warm (especially at high altitudes) and are strongly affected by sunlight. The humidity sensor measurements also tend to be a bit lower than they should be, although accurate humidity measurements are notoriously difficult to obtain.

Overall, our suite of sensors still does a fine job of showing how these meteorological variables change throughout the atmosphere. We often use these data to teach students about different layers of the atmosphere, the jet stream, clouds, etc.

Can you tell me more about the video cameras?
We currently use GoPro HERO5 Session cameras and an Insta360 camera. For the GoPros, we typically record at 1080p resolution and 60 frames per second (FPS). The battery life of these GoPros is rather poor, so we connect each camera to an extended battery pack that usually allows for up to 3 hours of continuous recording time. This means we can usually get the entire flight on video! Even with the battery pack, each camera is super lightweight (about 5 ounces), making them perfect for our launches. For a typical launch, we’ll send up three GoPro cameras: one pointing up at the balloon, one pointing sideways at the horizon, and one pointing down at the ground.

More recently, we’ve also started flying an Insta360 camera to record 360-degree video footage at 5.7K resolution and 30 FPS. All four cameras (3 GoPros + Insta360) are mounted in a custom camera box during the flight.

What do you do with the video footage?
Following each launch, the video footage obtained by the cameras onboard the balloon payload is downloaded and backed up to our computers. For our GoPro cameras, the total size of this footage (6–9 hours @ 1080p resolution and 60 FPS) is usually in excess of 100 GB! The Insta360 video footage by itself usually exceeds 100 GB as well! If participants would like copies of these raw unedited video files, we are happy to provide them. However, following most launch events—especially those involving K-12 students—we typically create a short (~5 minute) highlight video and upload it to our YouTube channel.

Can you tell me more about the backup GPS device?
For each launch, we send up a SPOT Trace GPS device as a backup in case our primary tracking device, the SatCom, fails during flight. The SPOT Trace sends the location of the payload to the internet (via the Globalstar satellite network) once every 10 minutes. On a full battery, it can continuously track and transmit their locations for several days. Thus, if we can’t recover the payload right away and have to come back at a later time, or if the SatCom fails, we will still be able to get location updates for quite some time after the payload has landed.

What happens if we lose signal from all the GPS devices on the payload?
This would be a very unfortunate situation, since we probably would never be able to recover the payload. If that were to happen, we would just have to hope that someone eventually finds it and returns it to us. We include contact information on our payload items for this very reason.

Can you tell me more about the radiosonde?
A radiosonde is a small instrument package that provides highly accurate measurements of air pressure, temperature, relative humidity, wind speed, wind direction, latitude/longitude, and altitude. It is sent up with a weather balloon and transmits its data via radio signal back to a ground receiver. We obtain our radiosondes from a German company called Graw. These radiosondes weigh only 90 grams (0.2 pounds) and transmit their data every 1 second during flight. We are able to monitor this data in real time on one of our laptops. The temperature and humidity measurements obtained by one of these radiosondes is much more accurate than those from the SatCom.

The data from a radiosonde is used to make a sounding. A sounding is simply a set of weather measurements collected vertically throughout the atmosphere. These data can be plotted on diagrams that help us visualize how the atmospheric conditions change with height.

Can I get the data that was collected by the meteorological sensors?
Absolutely! We do not typically use this data ourselves, so we are more than happy to send you the data if you would like to use it.

Is there anything we are NOT allowed to send up with the balloon?
Yes! Although the FAA does regulate high-altitude balloon flights, their regulations are almost 60 years old and do not really specify what you can and cannot send up with a balloon. We have therefore made our own rules about this based on what we deem to be safe and reasonable. At this time, we do not allow our payloads to include live animals, explosive or highly combustible items, or any other items that are illegal to possess. In addition, the maximum weight of each individual payload package cannot exceed 6 pounds (per FAA regulations), meaning that you are not allowed to send up something heavy like a bowling ball.

Are there limits to how much the payloads can weigh?
Yes! The entire payload (i.e., everything below the balloon) cannot weigh more than 12 pounds (5.45 kg), and no single payload package can weigh more than 6 pounds (2.7 kg). If the entire payload weighs more than 12 pounds, or a single payload package more than 6 pounds, then we must essentially get permission from the FAA to fly the balloon. There are a bunch of other hoops we would have to jump through as well. Overall, launching the balloon becomes quite a bit more complicated (see next question).

What are the FAA regulations regarding high-altitude ballooning?
You can read all about the FAA high-altitude balloon regulations here (see both Subpart A – General and Subpart D – Unmanned Free Balloons). Below is a basic summary.

If any of the following are TRUE:

• A single payload package weighs more than 6 pounds
• The entire payload weighs more than 12 pounds
• A single payload package weighs more than 4 pounds AND has a weight/size ratio of more than 3 ounces per square inch on any surface
• The payload uses a suspension device requiring a force of more than 50 pounds to separate the payload from the balloon
• Flying the balloon creates a direct hazard to other persons or their property (includes intentionally dropping objects from the payload)

Then the following restrictions apply:

• You cannot fly your balloon within certain restricted airspaces
• You cannot fly your balloon at altitudes where clouds are obscuring more than half of the sky
• You cannot fly your balloon at altitudes where the horizontal visibility is less than 5 miles
• You cannot fly your balloon if it will pass over a highly-populated area during its first 1,000 feet of ascent
• You cannot fly your balloon if its projected landing spot creates direct hazard to other persons or their property
• You cannot fly your balloon at night unless both your balloon and payload are equipped with flashing lights visible for at least 5 miles
• Your payload must be equipped with at least two independent cut-down systems or devices
• Your payload must be equipped with an appropriate radar reflective device
• You must provide appropriate advance notice of the launch to the nearest FAA air traffic control facility
• You must provide any balloon position reports and other flight-related information that are requested by the FAA

We do our best to comply with all the payload regulations, allowing us to be exempt from all these additional high-altitude balloon restrictions.

BALLOON LAUNCHES

How often do you do balloon launches?
We try to launch 6–7 balloons each year, or about one per month during the school year. We sometimes do one or two launches over the summer as well. Click here to see a complete list of all the launches we have done since 2014.

Why do people launch high-altitude balloons?
We launch weather balloons as a way to provide K-12 students throughout Wyoming with real-world STEM experiences and opportunities. However, the data collected by sensors on weather balloon payloads are extremely important to meteorologists, researchers, and weather forecasters. That is why weather balloons are launched every day by the National Weather Service at many locations across the United States. These data help meteorologists understand what is going on high in the atmosphere far away from all of our sensors on the ground. Data from these balloons are also used by computer forecasting models to simulate what might happen in the future.

Who else launches high-altitude balloons?
Lots of people! In fact, weather balloons are launched two times every day from more than 900 locations across the world, at the same exact time: 00:00 and 12:00 Coordinated Universal Time (UTC). In Wyoming, that’s 6:00AM and 6:00PM during daylight savings time and 5:00AM and 5:00PM during standard time. In the United States, these balloons are launched by 92 National Weather Service offices. The only National Weather Service office in Wyoming that launches balloons is located in Riverton.

Scientists and other researchers sometimes launch weather balloons for their own research projects. Instead of using the data from these balloons to make forecasts, they use the data for research to try and better understand how the atmosphere works. Ordinary citizens can launch weather balloons as well. This seems to be happening more and more throughout the U.S. in recent years. There are lots of videos of ordinary citizens launching weather balloons on YouTube. Finally, there are other groups like us that launch weather balloons with college and K-12 students as part of their educational outreach programs.

Can I launch my own high-altitude balloon?
Sure! There are many citizens across the country that have become involved with high-altitude ballooning. There is obviously a cost involved, mainly for the balloon and helium. You will also need to have some sort of GPS tracking device so you can recover your payload. The SPOT Trace GPS units that we use as backups could potentially be used as your primary tracker. Folks that are more technologically savvy could build their own tracking device if they are so inclined. A decent resource for anyone interested in getting into high-altitude ballooning can be found here.

Is Wyoming a good place to launch balloons?
We think so! There are not many people that live here and a lot of the land is public, so the chances of the payload landing on someone’s property or in a busy city are lower than elsewhere in the country. Even so, most of our payloads (75%) still land on private property. Additionally, while we do have a lot of mountains here, we also have a lot of open areas and rolling plains, especially in the central and eastern half of the state. These areas are easier to hike into if that’s where the payload lands. Finally, since Wyoming is near the middle of the country, we don’t have to worry about the payload landing in the ocean.

There are some drawbacks to launching balloons in Wyoming. The weather can be quite poor (windy, snowy, cold) during much of the year. Also, Wyoming doesn’t have a lot of roads, so it can sometimes be challenging to access certain areas by vehicle.

Will you launch anywhere in Wyoming?
There are a few locations in Wyoming where we would prefer NOT to do a balloon launch. This mainly includes areas in the northwest part of the state (i.e., Jackson Hole, Tetons, Yellowstone, etc.). Those areas are surrounding by mountains and our payload would most likely land very far from roads, in grizzly bear country no less! To successful launch a balloon and recover a payload from one of those locations, we would need to have absolutely perfect wind conditions high in the atmosphere, something that doesn’t happen all that often.

Do you launch balloons from outside of Wyoming?
No, at this time we only launch balloons at locations within Wyoming.

Do we have to let the FAA or airports know about our balloon launches?
If the payload complies with FAA regulations, then the quick answer is no. However, as a courtesy, we have started informing the FAA any time we plan to launch relatively close to an airport (within ~5 miles or so). This is done by submitting a Notice to Airmen (NOTAM) ahead of time, which basically lets any pilots flying into or out of that airport know about our balloon launch. Again, it’s not required, but it’s a good idea when launching near an airport!

Can bad weather affect a balloon launch?
Absolutely! The most common weather-related reasons for postponing or canceling a launch are high winds and heavy precipitation (usually snow). In Wyoming, wind is most often the culprit. Winds over 15 mph can make inflating a balloon outside very challenging. Winds over 25 mph can make launching the balloon nearly impossible (and potentially dangerous). We make postponement decisions on a case-by-case basis, but a forecast calling for high winds at the launch site or a significant amount of precipitation in the area will usually do the trick. Other non-weather-related factors can also have an impact on balloon launch postponements (see next question).

What other factors can affect a balloon launch?
Many things can go wrong before a launch that could force a postponement (e.g., problems with the GPS devices, a faulty balloon that bursts prior to launch, etc.). However, the most common non-weather-related factor that can impact a balloon launch is where the payload is predicted to land.

Payload landing locations that are deep in the mountains (especially in winter when the snowpack is deep), near large bodies of water, or far away from easily accessible roads can make it very difficult to retrieve the payload in a timely manner. Meanwhile, landing spots near large population centers or military bases can be problematic since we don’t want our falling payload to cause any hazards to people or property. Prior to launch, we always have a pretty good idea for where the payload will land, and if the landing area looks problematic we will consider postponing the launch.

Can we launch a balloon near a thunderstorm? At night? At sunrise/sunset?
Technically, the answer to all three of these questions is yes. However, we don’t launch near thunderstorms primarily because of the lightning hazard (both to the payload as well as to ourselves). We have not yet launched at night, although we have done a launch shortly before sunset and another shortly before sunrise.

RECOVERING PAYLOADS

What happens if the payload lands on private property?
This actually happens quite often, especially when we launch in the eastern half of the state. If a payload lands on private property, we will make a good faith effort to get in contact with the land owner. Most of the time this is quick and easy, although sometimes it can take a lot longer (perhaps days or weeks). The vast majority of the time, we do eventually find the land owner and one of the following happens: (1) the owner grants us permission to drive or walk onto their land to retrieve the payload; or (2) the owner retrieves the payload for us and brings it to us.

There are rare cases when it isn’t clear who owns the land (if anyone does at all), or we are unable to find their contact information. Those situations require a lot more thought and consideration about what our options are, and we approach these on a case-by-case basis.

What happens if the payload lands in the mountains or in a lake/river?
We have had the payload land in the mountains before, requiring us to hike many miles to get it. As long as we know exactly where it lands, even if it’s miles from a road, we will likely be able to retrieve it eventually. It might take a few weeks or months, especially if we have to wait for snow to melt, but we’ll be able to get it back.

We have not yet had a payload land in water, although we had one close call near Flaming Gorge Reservoir. If it were to land in water, some of our equipment is waterproof and would survive. Other equipment would likely be damaged. Most of our boxes would probably float, so we suspect that we’d find it rather quickly and eventually figure out a way to get it out of the water.

What happens if you launch in Wyoming but the payload lands in another state?
We have had payloads land in Montana, South Dakota, Nebraska, and Colorado. Recovering these payloads works the same way as if they had landed in Wyoming.

What is the longest/shortest distance you’ve had to walk to retrieve a payload?
The longest we’ve ever had to walk during a payload recovery was back in 2016. During one particular launch that year, the payload landed in the National Forest in the Laramie Range southeast of Casper. To get to it, we had to park our vehicle at a private ranch (with permission) and hike about 6 miles one-way on some old dirt roads. While it was quite memorable and scenic, we prefer much shorter hikes!

Speaking of shorter hikes, we have had payloads land on dirt roads, allowing us to drive right up to them. We’ve had payloads land a few dozen feet off of paved highways as well. While these types of recoveries are ideal, they are pretty rare. Most of the time, we have to get out of the vehicle and hike some distance (usually more than 1/2 mile) to find the payload.

Do you know where the payload is going to land before you launch?
We don’t know exactly where it will land, but we always have a really good idea of where it will go. Before the launch, we use the SondeHub Balloon Flight Predictor to get an idea for what the balloon’s flight path will be. There are other flight prediction websites out there too, but this is the one we utilize most often.

Basically, these websites use global weather forecasting models to get the predicted wind speeds and wind directions at various levels of the atmosphere for the time and location of your launch. Using some math, they predict the 3D trajectory of the payload as it ascends and then falls back to earth. On average, we have found that the predicted landing locations from the SondeHub website (obtained the night before the launch) are usually accurate to within 5–10 miles. At best, it has been 1 mile off of the actual landing location. At worst, it has been 19 miles off. Overall, it gives us a good estimate for where the payload will land and helps us decide if it’s worthwhile to launch on that particular day.

HELIUM

Is helium safe to use?
Yes, helium is a non-toxic inert gas which means that it will not explode or catch fire. The only real danger of using helium for high-altitude ballooning lies in the fact that it is stored under very high pressure (~2500 PSI) in metal gas cylinders. If its cylinder were to somehow rupture, the high pressure of helium inside could cause the cylinder to become a flying 150-pound projectile. Fortunately, such accidents are extremely rare and require extreme negligence. We always make sure to be very cautious when handling helium cylinders.

Can you use hydrogen instead of helium?
Yes we certainly could, but not anytime soon. It is true that hydrogen gas has some advantages over helium for high-altitude ballooning. For one, it is a lot cheaper since it is easy to produce (its supply is pretty much unlimited on earth). It is also lighter than helium which means it provides more lift per volume. However, hydrogen is also extremely combustible and therefore quite dangerous to handle. For obvious safety reasons, we prefer to stick with helium, especially for balloon launches with student participants.

Where do you get your helium?
We currently get helium through our chemistry supply room at the University of Wyoming. They obtain this helium from a large compressed gas supplier in the area. Rarely, we may choose to order helium directly from local suppliers and have the cylinders delivered directly to the launch location. Normally, however, we acquire and transport the helium ourselves.

Aren’t we running out of helium?
It may seem like it, but not really. Helium is one of the most abundant elements in the universe, although it is somewhat rare on earth. Helium is often found within natural gas that is extracted from underground. So in other words, we actually mine helium! It is then separated from the natural gas during the refinement process. Our understanding is that there is still plenty of helium underground to last humanity for quite some time. However, helium prices have indeed skyrocketed in recent years primarily due to the lack of helium availability. In other words, there is plenty of helium waiting to be retrieved, but we can’t retrieve it fast enough for the rising demand. If you’re interested in this topic, we suggest you read this old article from 2012 which explains the whole helium situation in a lot more detail.

MISCELLANEOUS

When did the Wyoming Space Grant balloon program begin?
We started our balloon program in 2011. However, the program really didn’t get up and running until Fall 2014 when we did our first K-12 launch with one of the elementary schools in Laramie. Since then, we have been launching balloons with K-12 schools across the state about once per month.

How can I request a balloon launch at my school?
If you are a K-12 teacher or educator in Wyoming and would like to have us come do a balloon launch with your school or organization, you can fill out our K-12 Balloon Launch Request Form. We cannot guarantee that we’ll be able to accommodate your request, but we will certainly respond and try our best to work you into our schedule.

How cold does the air get during a balloon flight?
Very cold. It’s normal for temperatures higher in the atmosphere to be lower than –60°F, and we have seen temperatures as low as –90°F.

What happens if the balloon or payload hits a plane?
We do get asked this question a lot. We are not currently aware of any cases where this has occurred. The aerodynamics around planes (especially large airlines) may help to push any balloons or payloads near the plane and out of harm’s way. Smaller planes move slower and would probably be able more quickly see and avoid a weather balloon.

What if I have a question that isn’t on this list?
If you have a question that wasn’t answered here, or would like additional information about our balloon program, please don’t hesitate to reach out to us via email: wsgc@uwyo.edu