The Guide


The goal of this project is to launch a weather balloon into the stratosphere with a small payload capable of recording the location and altitude, and taking photos with a camera. This is not a new thing; people have been doing this for decades and documenting their procedures. What’s new about our approach is that we’re just using an Android phone, and we’ve built an app specifically for it. This makes for a much smaller and easier package that has everything built in; no wiring or expensive components, and only minimal protections.

This guide is broken up into sections related to different parts of the project.


This discusses the balloon and gas used to fill it and the proper procedures for handling and filling the balloon.


There are actually two tethers; the first holds the balloon to the ground before launch, and the second connects the balloon to the payload. Also included in this section is the radar reflector, which is attached to the tether.


This is construction of the foam cage and impact zone, and the window.


How to acquire and configure the phone.


Installing the app on your phone, running the software, and uploading the results to


There are certain rules that apply to balloon launches, but mostly you’ll need to pay attention to FAA part 101. In applicability, it says:

(a) This part prescribes rules governing the operation in the United States, of the following:

…(4) Except as provided for in §101.7, any unmanned free balloon that—

(i) Carries a payload package that weighs more than four pounds and has a weight/size ratio of more than three ounces per square inch on any surface of the package, determined by dividing the total weight in ounces of the payload package by the area in square inches of its smallest surface;

(ii) Carries a payload package that weighs more than six pounds;

(iii) Carries a payload, of two or more packages, that weighs more than 12 pounds; or

(iv) Uses a rope or other device for suspension of the payload that requires an impact force of more than 50 pounds to separate the suspended payload from the balloon.

This means that as long as your payload is less than four pounds and has a rope with an impact force of less than 50 pounds, you do not need to follow any more of the FAA guidelines.

There is also a section 101.7, which details “Hazardous Operations”:

(a) No person may operate any moored balloon, kite, amateur rocket, or unmanned free balloon in a manner that creates a hazard to other persons, or their property.

(b) No person operating any moored balloon, kite, amateur rocket, or unmanned free balloon may allow an object to be dropped therefrom, if such action creates a hazard to other persons or their property.

We think a safely handling a hydrogen balloon doesn’t count as a hazard, and we are confident that the weight of the payload, choice of foam, and drag caused by the reflector and balloon are sufficient to not constitute a hazard when dropping.

Regardless, you should NOT launch a balloon near an airport or tall structures. While notification of the FAA is not a requirement, either, it’s polite and they might be able to tell you interesting stories or give you some good advice.

Additionally, we have added a radar reflector to our design, because we don’t want to give any pilots a bad day or a ufo sighting, especially since we’re using hydrogen.