In this guide we will detail step by step the choice and assembly of components as well as the logistics of the Viking I balloon launch. We strongly believe in a do-it-yourself approach, and our ultimate goal is to make near space exploration a commonplace activity for schools and hobbyists around the world. Through our usage of used and recycled components as well as some smart buying and a sponsorship (which we’ll talk more about), we were able to bring down the cost of a launch to less than half of any that we know of. This contributes to making launches not only more accessible, but simpler in general as all components can be found off the shelf and utilized without any extensive hacking, soldering, or technical know how.
Step 1: Acquire Equipment
Camera: The only requirement is that it have an intervalometer function (what allows the camera to take a picture every x seconds). We chose a Canon Powershot a470, a simple point and shoot camera popular for ballooning due to it’s ability to load the ‘Canon Hack Development Kit‘ a temporary firmware that can be loaded from an SD card. There are many pre built intervalometers that can be loaded as scripts through CHDK. To avoid blurry pictures from the craft spinning, we used CHDK settings to set the shutter speed to 1/800s. In future launches we are thinking about choosing a slightly slower shutter speed than this, yet not one image was blurry which goes to show that 1/800s is a sweet spot. With the camera set to take a picture every 5 seconds, used up about 3.6 gb of space during our three hour launch on an 8 gb SD card. Purchasing a 4gb card should be plenty, as even on maximum quality settings, 8 gb was overkill for us with this camera.
Note: The Canon a470 in particular has in issue with the screen not turning off. It’s important to save as much power as possible, so in order to turn off the LCD screen and backlight, we simply plugged something into the cameras AV/Out port.
Requirements: Intervalometer, 1/800s shutter speed, 4 gb SD card, lithium batteries.
For more information about our components, see the ‘Equipment‘ page.
For us, this simply involved cutting a hole inside of the soft cooler, building a small cardboard mounting bracket for the camera to nest in, and then using nylon rope to tie a knot around the soft cooler that left some slack to go up to connect with the balloon. The parachute (which tore from the rope at some point, so probably don’t take our advice on this) was tied and glued to the nylon rope in the center of the balloon train. Each soft cooler is different, but ours had a velcro pocket on the bottom of the zipper lid, in which we placed the GPS unit and a hand warmer sitting face up. This allowed the GPS to sit in a fashion so that it’s antennae was always pointed upward towards the sky. We’ll post pictures of this.
It goes like this: Cooler —— Parachute ——->Balloon.
3. Do the Math!
Be sure to run a balloon trajectory estimation before launching. Our favorite sites for this are the University of Wyoming Balloon Trajectory Forecast and the Near Space Ventures, Inc. On-Line Near Space Flight Track Prediction Utility. The near space ventures page is better since it allows for precise information.
We’ll update this page soon with our in depth calculations involving the maximum altitude, the amount of helium to use, and how to properly fill in each portion of the Near Space Ventures Tracker.
4. Launch Day Check List
1. Ensure all equipment is in working order and at hand.
2. Place the camera and GPS inside the soft cooler, for us this involved turning the camera on intervalometer mode with a 10 minute delay before taking the first picture. Then we placed it so that the camera sat on the cardboard mount with the lens pushed inside of the viewing hole. We used simple packing tape to tape the cardboard to the sides of the cooler so that the camera was firmly pressed against the side.
3. To fill and tie the balloon, follow this guide: Youtube Video and written guide.
4. Secure the payload to the balloon using the long piece of string like in the video. We also tied the nylon rope from the soft cooler to the balloon as well to allow for a potential fail safe.
5. Make sure the camera is taking pictures (you can hear it click every interval), and then release the balloon!
It will take a couple hours for the balloon to land again, but start planning your recovery right away. We drove east to nearby Boulder City and used my grandfathers house there as headquarters to track the balloon. Spot GPS updated every ten minutes until reaching 60,000 feet, at which point we lost contact and didn’t hear back from the balloon for about an hour. We were very nervous that something had happened, but thankfully contact with the balloon resumed as it fell back to earth. Be sure that the balloon updates twice in the same location before you leave to get it, and bring your favorite geocaching equipment with you. We didn’t have the luxury of this on our first launch, but it’s almost essential, especially when the balloon can end up miles away from any road or sign of civilization.