Every astronaut talks about the awe of seeing the blue glow of Earth from orbit. Oliver Yeh and Justin Lee, both MIT students, wanted to see Earth from above, too. They built a contraption that was able to fly to the upper reaches of the atmosphere and take photographs from high enough up to show the planet’s curvature and the blackness of space beyond. Though many devices have been built that could achieve this feat, their setup was uniquely inexpensive:
it cost less than $150.
A weather balloon, which cost about $20, propelled the photo equipment to approximately 93,000 feet over about four hours. As planned, the thinning atmosphere then caused the balloon to pop, and the equipment descended in about 40 minutes with the aid of a parachute. To predict where it was likely to land, Yeh and Lee used a website maintained by the Department of Atmospheric Science at the University of Wyoming that assesses wind direction and strength. (They suggest that those who want to undertake similar projects inform the U.S. Federal Aviation Administration and check federal and local regulations first: strict laws govern the use of airspace above certain heights.)
Yeh and Lee tested parachutes by attaching them to a styrofoam cooler filled with eggs and dropping it off the roof of a five-story building. Eventually, they found a design that allowed the eggs to land intact. They found that they could use a variety of materials to make the parachute–even a trash bag.
To keep the equipment from failing in the chill of the upper atmosphere, Yeh and Lee packed it in a protective cooler. For additional warmth, they insulated the camera and phone with newspaper and put chemical hand warmers next to each device. They carved a hole in the cooler for the camera’s lens.
Yeh and Lee modified an off-the-shelf Canon A470 camera by installing open-source software that instructed the device to snap a photo every five seconds. The images, covering almost five hours in flight, were stored on an eight-gigabyte memory card.
A low-cost GPS tracking service turned a Motorola i290 prepaid cell phone into a GPS transmitter. Besides allowing Yeh and Lee to track the flight path, the information broadcast by the cell phone was key to retrieving their equipment and collecting the pictures stored on the camera.
Lithium batteries designed to function down to -40 °C powered both the camera and the cell phone. The phone was also plugged into a battery-powered charger as backup during the flight.