Photos From the 2017 Eclipse

Like many others, we sent up a weather balloon to observe the 2017 solar eclipse. The balloon took a few great pictures of the shadow cast by the moon on the earth! A link to an album with more photos is here. The photos below were taken with the Xiaomi Yi action camera, which is a great cheap GoPro alternative. We also sent up a Samsung gear 360 camera to take panoramic photos, but it was mounted outside the insulated payload compartment and stopped functioning before the eclipse was visible.




A flight aboard the NASA High Altitude Student Platform (HASP)

The NASA High Altitude Student Payload (HASP) project provides a spot on a high altitude balloon payload for undergraduate and graduate students. When I heard about this last year, I gathered a team together, we applied and were accepted into the program. Our project: launch infrasound microphones into the stratosphere. Infrasound (sound at frequencies below audio range) is usually measured at the Earth’s surface, but we know it propagates hundreds of kilometers upward into the atmosphere. Our goal is to measure these sound waves as they cross the stratosphere.

The HASP project was definitely a commitment. As the team leader, I was required to write a monthly status report letting the HASP project leaders know what I was up to. I had to build my payload box under strict power draw, weight, and size limits. I also had to learn electronics from the ground up. Thankfully, another member of our team had lots of experience in electronics, so it wasn’t so bad.

Our Omnirecs DataCube logger installed in the payload box.

Our Omnirecs DataCube logger installed in the payload box.

A few weeks ago, I traveled to Palestine, Texas to bring my payload to the Columbia Scientific Balloon Facility (CSBF). There, our payload was subjected to extreme temperatures (ranging from -50 to 50 Celsius) and pressures (sea level to stratospheric).  We passed the test, recording the 8 Hz signal from the vacuum pump clearly even when the pressure was around 5% of sea level.  This was an important milestone: not only did it clear us for flight, but it also showed that our differential pressure microphones (constructed by Dr. Jeff Johnson at Boise State University) would operate in a near vacuum, something they were not designed to do.

Our payload about to face the thermal/vacuum test.

Our payload (the white box with the UNC logo) about to face the thermal/vacuum test.

From Texas, I traveled to New Mexico to launch our payload into the stratosphere.  I ended up staying in my home town, about 2.5 hours from the launch site at (a CSBF facility in Ft. Sumner, NM).  Needless to say, I spent a lot of time on the road!  I had to drive there and back three times: once to put my microphones on the flight ladder (see below), another time to make sure everything worked during the “hang test” (a dry run for launch), and finally for the big day itself – the flight.

CSBF staff mounting the infrasound microphones on the flight ladder.

CSBF staff mounting the infrasound microphones on the flight ladder.

Like any balloon flight, this one depended on the weather.  This time, the news was not good.  One group was ahead of HASP, and they had dibs on each launch window.  They tried twice, and were not able to fly both times.  I had to fly home on Saturday, so I showed CSBF and HASP personnel how to set up my payload, and I resigned myself to not seeing the balloon fly.

But as luck would have it, the previous team decided to wait, and a launch window opened Saturday morning, the day I was scheduled to fly home.  Since the flight was early in the morning and my plane ticket was for early afternoon, I decided I was going to go see the launch.  I drove out, arrived in Ft. Sumner at about 10 PM, slept in the back of the car for a few hours, then got up at 2:45 AM Saturday morning to start getting ready.

It's about 3:45 AM, and CSBF staff secure the microphones after I powered them up about 15 minutes before.  The wheel on "Big Bill" (the launch vehicle), is taller than I am.

It’s about 3:45 AM, and CSBF staff secure the microphones after I power them up. The wheel on “Big Bill” (the payload vehicle), is taller than I am.

The launch was touch and go the whole time – we had to wait for the winds to all blow in the same direction for the first 1000 ft in order to start the inflation process.  As luck would have it, they did straighten out, and the call was given to roll out and start inflating the balloon.

The balloon reaches full inflation about a half hour after sunrise.

The balloon reaches full inflation about a half hour after sunrise.

The launch was spectacular.  The balloon was released and drifted into the air.  Big Bill started driving in the direction that the balloon was going, and just when it was overhead, the payload was released.  The entire structure (800 ft high!) was now in free flight.  It seemed to climb slowly, but that was an illusion – when the balloon was 12,000 ft above the ground it still seemed close enough to touch.

The radio crackles and says "it's your balloon."  With that, the 3 million cubic ft envelope is released and begins climbing into the air.

The radio crackles and says “it’s your balloon.” With that, the 3 million cubic ft envelope is released and begins climbing into the air.

Here we go!

Here we go!


The balloon flew for about 8 hours, and was terminated over northeast Arizona.  Once the recovery team picks it up and ships us our data logger, we can find out what we heard up there.

A big thanks to the Louisiana State team for running HASP, and all the great people at CSBF who made it all happen!

Balloon from Floral Arrangement Flies 135 Miles

Ever wondered how far a party balloon can fly if you let it go, and how long it stays in the air?  Turns out they can fly for over a hundred miles and for at least 8 hours or so.  I discovered this when I released an aluminized party balloon from the UNC Chapel Hill Campus with my email address attached.  This afternoon, I got an email from a resident of Pantego, North Carolina – a sleepy town of 200 people located right near the seashore, about 135 miles from Chapel Hill as the crow flies.  She found it in her front yard at about 10 AM today.

This is an example of the type of balloon I released. I think the inside’s coated with aluminum, as opposed to the stretchy ones you blow up with air.

I released it at about 8 AM yesterday morning, so it probably arrived sometime last night.  I’m actually surprised it travelled such a short distance given that it was in the air all day – but it could be that it did not take a direct flight path, stayed low to the ground (where winds are milder) or landed yesterday and she just didn’t see it.

She said that there were no rips in the balloon, so it must have lost its helium in transit.  This is rather surprising, since it sat in my lab for about 2 weeks and only lost about half its volume.  I assume that the increase in internal pressure compared to external pressure as the balloon rises increases the rate of helium loss.

The reason I had this balloon is because I recently passed an exam, so my mom sent me a floral arrangement with a balloon that said “Congratulations!  You did it!”  Initially I was curious to see how long it would take to lose its buoyancy.    Once it was clear that the end was near, I figured it was a pity to waste a perfectly good balloon, so I attached a message and let it go.

Launch: 8 AM, March 11th, at 35.908101 North, -79.052106 West

Landing: Sometime before 10 AM, March 12, at 35.589202 North, -76.662261 West

High Altitude Balloon Localization from Photographs

On December 24, 2011, we launched a high altitude balloon equipped with a digital camera and a SPOT GPS tracking device. You can read more about the flight and recovery in this post. The SPOT tracker transmitted latitude/longitude data (but not altitude), and did not transmit above ~20,000 ft. For a while we have been interested in reconstructing the flight path of the balloon based on the pictures taken throughout the flight.

title_pic_blackIt is possible to find the position a photo was taken from given the (x,y) locations of landmarks in a picture and some knowledge about the field of view of the camera. In the picture above we use the positions of two mountain peaks and a triangular reservoir in Socorro to find the position of the balloon. We experimented with two methods:  a method that used three landmarks and a Newton-Raphson solver, and a method that used N landmarks and OpenCV, an open source computer vision library.  The method with OpenCV is more accurate because it can use many landmarks, and also takes into account camera distortion. Using this method we reconstructed the flight path of the balloon, which is shown below. We found out that the balloon burst at around 91,250 ft, and that the winds that day varied significantly with elevation. You can read a detailed write up of both of the methods here, and the code we used is available here. We figure that there are at least a few other people out there who have pictures from a high altitude balloon flight but no GPS data.  If you are in this situation and want to know how high your balloon went, this is the way to go.


Cluster Ballooning with Helium Filled Leaf Bags

Cluster ballooning – using multiple small balloons instead of one large envelope – has been around for a while.  The guy who flew to 26,000 ft in a lawn chair used cluster balloons, and I think others have done similar stunts.  The animated movie “Up” involves an entire house flown using party balloons.

Despite this, I never thought I would be involved in a cluster ballooning project.  First of all, I have no intention of ever flying in one of my balloons.  I’ve seen too many things go wrong to ever do that!  Second, it’s a huge waste of weight.  One large balloon weighs much, much less than 10 balloons with the same cumulative volume.

However, I recently had an experience below that’s caused me to reconsider.  Mind you, I still would rather use weather balloons for high altitude launches.  But when weather balloons are unavailable, or you want your payload to cruise at lower altitudes and the weather isn’t perfect for solar balloons, you can get away with cluster ballooning.

In fact, you can head to your nearest hardware store, and buy a bunch of leaf bags.  Fill them up with helium, tie them shut, and string them all together.  Once you have enough, you can lift a payload just like you could if you had a weather balloon.  In the photo below, you can see our leaf bags lifting a microphone array into the air during a geophysics experiment:

Our leaf bag balloon lifts a string of infrasound microphones above the trees.

Our leaf bag balloon lifts a string of infrasound microphones above the trees.

We learned a thing or two when we threw the cluster balloon together.

1.  Buy the largest and lightest bags you can.  Also, use clear plastic if possible (it’s stronger).  When evaluating bags, look for the thickness.  The thinner the bag, the lighter it is.  Also, the larger the bag, the lower the surface area to volume ratio – meaning more lift.  We found some 40 gallon clear leaf bags at Wal-Mart that did the trick for us.  We added the black bags later when we still had helium left over.  On this subject: you will need a LOT of bags.  We used around 70.

2.  Use a tube to convey the helium from the tank to the bags.  We bought around 6′ of tubing that we could fit right over the helium valve, allowing us to pipe the helium to where it was needed.  Also, it’s tricky to get the helium in the bag without a lot of it spilling out.  Be ready for some trial and error.

3.  Tie the bag shut, then ziptie the attachment strings above the knot.  Helium happily diffuses through everything – don’t give it the opportunity to escape or you’ll have a lot of empty bags, fast.

3.  Layer your bags.  Start with short strings, so that the bags are close to the attachment point.  Then, add more bags with strings long enough to clear the first layer.  The reason: helium leaks through the attachment points even with your knots and zipties.  So you want all the knots at the bottom, so that the helium floats up against the tops of the bags, not against the knot.

4.  Have at least three people to help.  Even then, it will take a long time to get serious lift.  We had an assembly line going and it still took around an hour.

Here’s the leaf bag assembly line:

Adding more helium filled leaf bags for more lift.

Adding more helium filled leaf bags for more lift.

Here’s a picture of the bags tied together:

Looking up at the cluster balloon.

Looking up at the cluster balloon.

So what were we doing lifting infrasound microphones with leaf bags?  It’s a long story.

I had the idea recently of flying infrasound microphones above volcanic explosions to determine if the sounds they produce are stronger above them or to the side.  Since flying microphones above real volcanoes is challenging to say the least, I had the opportunity to participate in a series of experiments designed to emulate volcanic explosions on a smaller scale.  This initiative was called “Man Made Maars” and was lead by the Center for Geohazards Studies at the University at Buffalo.  My initial plan was to use a tethered weather balloon to lift a series of three microphones above the explosions.  To this end I purchased 2 weather balloons from Kaymont – each was 350 grams (the smallest weather balloon they sell).

Little did I know that such small balloons have a narrow nozzle, and it’s hard to hold onto them while inflating.  One of my best friends found this out the hard way when the balloon slipped through his fingers and flew off into the cool upstate New York morning – before we had collected any data.  Luckily, I still had one balloon, so I flew the microphones till around noon when the winds got too high.  I then brought the balloon down, intending to deflate it and use it for the second day of experiments as well.  I foolishly tried to untie it myself, and ended up popping it.  The cool gust of helium smelled of defeat, even though helium is clearly odorless.

I still had over a tank of helium and 6 more explosions to go – and no way to lift my array.  But one of the other grad students with me asked why we couldn’t simply fill garbage bags full of helium.  I realized that not only would this work in principle, it would work in practice:  a high school student had already used a similar system to fly a camera above the clouds in Nevada (see the link here).  So that’s what we did – and we collected data from 5 of the 6 explosions on the second day.  The array was in the air for 5 or 6 hours, and although it blew around quite a bit in the wind, it maintained positive buoyancy the entire time.


Jake VI – Successful Test of Cutdown

I’m happy to announce that we had a major success last weekend.  My friend launched a weather balloon carrying a GPS and an Arduino computer programmed to cut the cable on the balloon at 20,000 m (~66,000 ft).  This launch, designated Jake 6, carried out its mission perfectly.  The payload separated from the balloon 20 kilometres above the snow-covered Minnesota landscape, then parachuted down for a safe landing in a tree.  The descent was a little scary as we watched our payload parallel, then cross the Mississippi River!  We knew it was about to land, and it would have been a very poor ending to the day to have it splash down in the brutally cold water.

Click here for a video of the flight!  A good photo taken from the air is below:


What went right:

-Successful cutdown at 20 kilometers.

-Detailed GPS data of the flight

What went wrong:

-The GPS did not get a fix until about 10 kilometers above the ground, which means we lost some data on the ascent

-The camera was accidentally programmed to take RAW format images, which means it ran out of memory at around 10 kilometres.  Still got some cool pics though!

-Our faithful parachute had to be left behind in the tree, despite my friend’s valiant recovery of the payload box


17 Miles above New Mexico – A High Altitude Balloon Flight into Near Space

I’m back after a brief intermission to tell you how to do one of the neatest things I have ever done-flying a camera on a weather balloon into the mid stratosphere, where the sky is black and the horizon is curved.

We are definitely not the first people to do this; in fact it seems like every other day I hear about some high schooler launching a balloon into near space.  But when it comes down to it, who cares how many times it’s been done?  The pictures are spectacular:


A YouTube video with the photo sequence and some cool music:

Want the individual pictures?  Have the entire photo set!

Note:  the photos are released under the Creative Commons with Attribution license.  If you display the photos for anything other than home use, please caption them with “Courtesy of Bovine Aerospace”.

How to do this yourself

The goal is to get a camera really, really high.  You could use rockets, of course, but they are hard to build, very regulated, and have a tendency to explode.  There is an easier way, however-just use a really big balloon.  Here are the things that have to happen for this to work:

1.  You need to lift the camera and protect it during flight.

2.  The camera needs to either record video or take photos every so often.  We did the latter.

3.  The balloon needs to release the camera so you can get it back.

4.  You need to be able to track the camera so you can find it again.

5.  You need to slow the camera on the descent so it doesn’t smash itself into smithereens.

6.  Last but definitely not least, the camera needs to land in the appropriate place (i.e. not water, rough terrain, or a military base).  We had some issues with this…


weather balloon


SPOT tracker

GPS cell phone

styrofoam cooler



ripstop fabric

helium tank


hand warmers

Lifting the camera

We used a Canon A530 camera (around $30 used on Amazon) and we used the CHDK package to make it take a picture every 10 seconds.  If you are not a programmer, either buy a camera that you can set to take a picture every so often or use a video camera.

We bought a Styrofoam cooler to protect the camera, and we threw in some hand warmers to keep it warm (it gets cold up there…like -90 F).  We also had the tracking system in the cooler (more on that later).

We used a 600 gram weather balloon from Kaymont to lift the cooler.  You can fill the balloon with hydrogen or helium.  We used helium.  It’s available from welding supply shops (you can buy 200 cubic feet for around $80, we used about half of that).  Hydrogen is cheaper and will give you slightly more lift but it is harder to find and also extremely flammable.

Here we are with our balloon, parachute, and instrument package:

Once the balloon reaches a certain height (75,000 to 90,000 ft, for our balloon), it pops and the styrofoam cooler starts its descent.


You must track your balloon in order to get it back.  Otherwise, unless you are extremely lucky and find your camera or someone else finds it and mails it to you, your camera will disappear into the sky and never be heard from again.

There are a couple of ways to track your camera.  If you have good cell phone coverage where you expect the balloon to land (see section below on landing prediction), you can use a GPS enabled smart phone with the free Instamapper app.  However, if you are concerned that the balloon might land in a place with poor cell reception, use the SPOT tracker.  We used both Instamapper and SPOT.  The cell phone never answered on the way down, so if we hadn’t had the SPOT we would never have gotten our photos back.

If you are into HAM radio, you could also use radio telemetry.  I think there are websites that describe how to do this but I have no personal experience with it.

The Landing

A styrofoam cooler that falls 17 miles will hit the ground pretty hard.  We found this out on the first launch we tried (we think the parachute failed…we never found the camera).  So it is very important to slow your falling camera down with a well made parachute.  You can buy parachutes online, but my friend and his girlfriend ended up making ours out of ripstop nylon.   Here’s a picture of the parachute:

You can use this online calculator to design a parachute that will work for you.  I believe that you want your camera to land at less than 15 mph.  After our first failure I was very conservative and designed ours to land at 6 mph. As I recall the cooler was undamaged (and styrofoam is pretty fragile!).

If you decide to design your own parachute, you can use this website to make a sewing or taping pattern.  I also have a python script that will generate half sphere gores, and when I post it I’ll add the link here.

A couple of parachute construction notes:

Make sure that the parachute is a long way below the balloon.  That’s because the shreds of material created when the balloon bursts can get tangled in the parachute and prevent it from opening…bad news for your 17 mile fall.  Also, put in a spreader (a circle of tubing) near the parachute to make sure it is slightly open, so that when the balloon pops and the whole thing starts to fall, the parachute can open.  Here’s a photo of the balloon in flight; note how far the parachute is from the balloon:

Predicting Where the Balloon Will Go

Balloon flight prediction depends on weather prediction.  If the weather prediction is accurate, then this website will give you a very good idea of where your balloon will end up.  If the weather prediction is not accurate…good luck.  In our case, a snowstorm had just passed, and the jet stream was swinging north.  Since the winds were changing direction so quickly, our balloon actually landed 50 miles south of where we predicted.  That’s why it ended up in the mountains, and that’s why it took a 3 day hike to get it back.

A Final Note on Legality

What we did was legal under FAA regulations.  However, it is your responsibility to ensure that whatever you do is legal.   Find the regulations here.  If you are not sure, contact your regional FAA office.