Balloon Mapping I

Introduction: For Activity #3 we began constructing  two different types of balloon mapping methods. The first one will be done with a digital camera attached to a balloon filled with helium that will be held to earth with a long string. The second one will be free to float into the atmosphere as far as it can reach until the reduced air pressure will allow the balloon to expand and eventually explode. This is also known as HABL(High Altitude Balloon Launch). Thus plummeting back to earth where we will search for it by means of a GPS tracking device that will be aboard our makeshift space capsule. But, the main point of this initial exercise is to come up with the basis of operation and implementation as to have a successful balloon launch, but also to limit unexpected errors by proper preparation.

Method: One of the first items that needed to be addressed is the weight of each individual piece of hardware. 


Weights of all hardware that may be needed for the balloon launches.

Balloon Mapping
In the Balloon Mapping project we will be launching a balloon filled with helium up to take photos of an AOI(Area Of Interest). In this project the balloon will be attached to a string, so this will be for a smaller AOI then the HABL. List of hardware needed for this project.
5.5' Chloroprene balloon
1000m of string
Various zip ties and rubber bands
Digital Camera(light and small, continuous mode ability)
Covering for the camera(2 liter soda bottle cut in half)
Snap Swivels
1.25" steel ring
Helium




Sample of balloon mapping. From top to bottom: Balloon, camera, string and finally a human.




Design 1 of a covering for the camera.

Design 2, the Hindenburg

First, build the camera enclosure: Here are a couple of examples of enclosures for the camera. Notice that both examples have 'wings' to help stabilize them in the wind.  Design 1 is taken from an actual balloon mapping kit, Design 2 is more of an original idea by a couple students. My opinion is the first design looks like it would be more stable and mounting the camera would be easier.


Second, figure out a way to attach camera into enclosure.  In the picture below, student tied a string into a loop and wrapped the string around both sides of the camera. Not seen, but the student is holding the camera up by the two loops above the camera. These loops that are being held by the student will then be slipped through the top of the enclosure(Design 1) and attached to the balloon string.

Third, getting the 'take picture' button on the camera to be compressed while the camera and balloon are airborne. As seen above there is an orange rubber band holding a small piece of eraser down to ensure that the 'take picture' button is held down continuously. Again, the camera must be in continuous picture mode when sent up.

HABL-High Altitude Balloon Mapping
The second part of the project is to send a balloon into the shallow atmosphere with a camera recording the land as it ascends. The idea of this project is essentially the same as balloon mapping except there will be no string to hold onto to keep the balloon earthbound and there will be severe cold to deal with as well. Below is a simple graph of Temperature vs Altitude.

To help combat the effects of the sub-freezing temperatures the camera will be mounted in a stryofoam minnow bucket surrounded by heat pads.

The idea is the place the camera into the bottom of the minnow bucket so as the bucket ascends into the air the camera films the shrinking landscape. In the picture below a hole has been cut to allow the camera to take pictures through the bottom of the bucket. The camera will then be covered by heat pads then covered by a piece of styrofoam insulation. See bottom picture.

 

As the balloon reaches high altitudes the pressure will become lower. So low in fact that the pressure inside the balloon will cause the balloon to expand and eventually pop, causing it to descend back to earth. So, that is where the parachute comes into play. As the minnow bucket descends the parachute will deploy and keep the bucket from crashing back to earth.

Discussion: The designs for the Balloon Mapping were pretty straight forward due to some information readily available on the web and with the balloon kit that was brought to class. I think the biggest challenge will be with the HABL. Keeping below the recommended payload weight of 2 pounds and keeping the camera not only secure, but warm. Some of my concerns would be not only the camera getting cold, but condensation on the lens. Sealing the camera enclosure in may be an option.

Conclusion: There were a lot of different things going on as for testing and experimenting. We've got the concrete stuff down like weights and a solid idea of what we want to do and how. There is fine tuning needed to be done when it comes to attaching enclosures to the balloon and keeping the camera warm for the HABL. Overall a lot of foot work got done on our first day on this project, now it will be finalizing our designs and then some practice runs.