High Altitude Ballooning!

High Altitude Ballooning (HAB for short) also known as near-space ballooning is a recently popular hobbyist activity rooted in science and exploration. A weather balloon filled with helium is launched with a parachute/payload and recovered using a GPS (in our case, a SPOT tracker.) The balloon expands at the higher elevations because the air is so thin to the point where the balloon busts and drops back down to Earth, hopefully recoverable.

The Payload:
Our payload for the launch will consist of a video camera, still camera, GPS unit, and in-flight computer. We will use a GoPro Hero3+ video camera for an amazing video of Earth. A GoPro was used to film when Felix Baumgartner jumped from 127,000 ft. during his record breaking “Red Bull Stratos” jump. (We really hope for excellent weather because the video and pictures will be that much more amazing.) For the still camera we will use a simple Canon Power shot, which will be programmed to take pictures every 10 seconds. (The last launch yielded 3000 pictures! Below are a few of those pictures, but notice the slight fogging on the lens due to the cloud condition and the fact that it is -50 degrees at 100,000 ft.!)

The In-flight computer will be an Eagle Flight Computer made by high Altitude Science (a company developed by a former flight controller for NASA.) The Eagle Flight Computer is tested and built for the conditions of our flight, and seems like the most reliable flight computer on the market for our purposes. With this computer, we will be able to measure and record (in six second intervals) the pressure, humidity, temperature, GPS location, and wind direction of our flight. Once the computer is recovered and interfaced with a desktop we will be able to view and analyze this information with Excel spreadsheets and brought into the classroom.

For the purposes of our launch, we will be using a 1000-1200 gram balloon with approximately 150 ft3 of helium in order to reach the 100,000 ft. marker depending on the payload we lave. The entire trip takes about 3-4 hours from ascent, apogee, to landing. Then we need to go and recover it. Our last balloon launch landed just outside Oakridge. We hope to get as lucky, but everything will depend on weather (the jet stream) and our Math to get the ascension rate as quick as possible and still reach 100,000 ft.+.

There is tons of information on the Internet if you would like to find out more about High Altitude Ballooning. In the links section of our website, we have listed a few resources as well.

High Altitude Balloon Launch – June 8, 2014 – Altitude: 91,080 ft.

We are happy to report that the June 8th Launch was successful!  A team was able to recover our payload on this nice sunny day, and we all had  fun doing so. Here is the report….

We launched from Edison Elementary, again to incredible weather with a slight wind to the East and no clouds in sight. The GoPro was able to record video for the entire journey, including when the balloon burst.  We also were able to record and recover the data with our High Altitude Science in-flight computer.  As before, we have written computer programs to translate the data from that computer and turn it into charts readable for our students. We were not able to get the Canon Powershot camera, facing upwards toward the balloon, to record past 6o minutes, once again.  This was unfortunate, and in retrospect we probably should have gone with the Raspberry Pi instead, but we hope the GoPro images and video will make up for this.

We retrieved the balloon off of Goodman Trail from the Hardesty Trailhead just South of the Upper Lookout Point Reservoir. As you can see from the pictures, we had to veer off the trail for a while, but the hike was easily manageable. The payload was able to maneuver itself through the trees to the forest floor. Once again, surrounded by very tall trees, we were somehow able to avoid getting our payload caught in one. Take a look at the video for the exciting descent!

A few thoughts on the altitude… We were clearly shooting for 100,000 ft+ and the 1200 gram balloon had the capability to go over 110,000 ft. It only went 91,000 ft. and here is why: It had too much helium this time around.  It rose very quickly, which was nice, but this meant it had less room to expand and therefore wouldn’t rise to a higher altitude.  This was not our intention, but this is what happened. We think we were not able to get the correct amount of helium into the balloon and this is why:  When we calculated the amount of helium and made the conversion from cubic feet to psi (because that is what our meter read) it looks like we did not account for the outside temperature where the temperature being less than 70 degrees would greatly change the pressure, and thus the amount of helium it looked like our meter was measuring. We emptied what we thought was 1400 psi of helium in the balloon today and that (as we understood it) should have equaled to only 95 Cft. of helium….Clearly this was not correct because the rise was extremely fast (2 hrs. up and down) and it popped at 91,000 ft., which is what we would have expected from a balloon that is filled too much. We did do our research, but in the spirit of following the Scientific Method, we need to go back, research some more and figure out the correct conversion from cubic feet to psi, and/or solve the mystery of why 1400 psi was too much helium for our balloon when we thought it was going to be too little. We still need to go back and do additional research to greater control this variable.

We used this formula: Total Lift Required= Weight of Payload + Weight of Balloon +Positive Buoyancy (Weight of Payload/2).

Then, Total Lift Required (in grams) multiplied by .035 to get Cubic feet of helium required.

TLR= 1433+1200+716

TLR= 3349 x .035

TLR= 117 Cft. of helium

This seems correct, but the variation of pressure as measured in psi seems to be the variable depending on the outside temperature and made it difficult to determine the exact amount of helium going into the balloon.  Either way, next time we know to shoot for 125 Cft. of helium however we determine is the best way to come to the correct measurement. Below are some of the charts we made for student analysis. The KML file will require Google Earth and show the actual flight path.  Please click the link to download or view.

Altitude v. Time  Ascent
Altitude v. Time Descent
Humidity v. Altitude Ascent
Humidity v. Altitude Descent
Pressure v. Altitude Ascent
Pressure v. Altitude Descent
Speed v. Altitude Ascent
Speed v. Altitude Descent
Temperature v. Altitude Ascent
Temperature v. Altitude Descent

High Altitude Balloon Launch – May 31, 2014 – Altitude: 106,424 ft.

Here is the story from our first launch…We launched our High Altitude Balloon at 10:45 am from Edison Elementary to great weather and hardly a cloud in the sky.  Once we let it go, it traveled due South along. We could see it for a very long time.    We followed its progress on a laptop from the SPOT tracker we mounted onboard. It was still sending us a signal when we broke for lunch. We regrouped at 12:30 to check in.  By that time the SPOT tracker had not been sending us a signal for quite some time.  About 2:30pm the signal finally showed up on the computer.  We watched with anticipation as the signals came in every 10 minutes.  We needed to wait for one of the signals to send us the same GPS coordinates twice in a row, so we know that it had landed.

After a few signals came in, the tracker stopped sending us signals.  This was not good and was not what we expected!  We knew the vicinity where it landed by the previous coordinates, but without a second signal the search area was going to be at least a few square miles approximately 20 miles SE of Cottage Grove, in the middle of the woods.

We prepared to drive out and retrieve it about an hour later, and as we were driving we checked one last time to see if another signal had come in.  It did!  Two more signals came in, and the same location,  almost an hour and a half after the last one back at Edison.  This allowed us to pinpoint the exact location of the payload, at least that was the theory.

We travelled SE of Cottage Grove up and down forest roads, all of which were paved. (Lucky!) We did worry about the fact that many of those roads are closed and locked, as they are owned by logging companies or BLM. We drove to where the coordinates pointed were the last location and parked, as that was as far as we could go.

We had to traverse down a steep wooded ravine about a hundred yards, where we met a creek.  About a hundred feet from where we came down, we spotted our red parachute hanging in the trees!  We discovered that there was a good chance that the payload was stuck in the trees originally (pointed down) since the SPOT tracker was not sending us a signal, and then after a while the wind blew it out of the trees. It was intact, safe, and looked like it was still operating.

Our analysis: We did discover a few problems once we plugged everything back in.  The camera facing upward stopped at 1 hr. into recording.  We are unsure why, but we think it switched to a default setting once it was turned off.  Second, as you will notice, the GoPro video abruptly stops.  Evidently, we experienced human error and forgot to delete the contents from the memory card after our initial test, which didn’t leave enough room on the memory card to record the entire voyage.  We do believe the last recorded image at just before the burst at 106, 000 ft. The in-flight computer was operating the entire time and we were able to retrieve all the data and will bring that into the classroom for analysis.

Second attempt: We may attempt to send up our second balloon, but we are a bit concerned about the difficulty retrieving it if we launch from the same location.  It seems quite lucky on our part to have it land where it did.  It could have easily landed in the top of a 100ft tree or in an area that is not accessible, and would be lost.  We are determining what to do based on the upcoming weather and wind direction and will keep everyone posted.

Watch the GoPro video:

Altitude v. Time  Ascent
Altitude v. Time Descent
Humidity v. Altitude Ascent
Humidity v. Altitude Descent
Pressure v. Altitude Ascent
Pressure v. Altitude Descent
Speed v. Altitude Ascent
Speed v. Altitude Descent
Temperature v. Altitude Ascent
Temperature v. Altitude Descent

Rocket Launch