When a rocket was launched by NASA last month, it brought three smartphone satellites into orbit (see photo). This move was part of NASA’s PhoneSat mission, which is tasked with determining whether a consumer-grade smartphone can be used as the main avionics of an inexpensive satellite. The satellites—comprised mainly of the smartphones—will send information about their health back to Earth. They also will attempt to take pictures of Earth using their cameras.
Transmissions from all three “PhoneSats” were received at multiple ground stations on Earth, indicating that they were operating normally. Large images are transmitted in small chunks and then reconstructed through a distributed ground station network. The PhoneSats remained in orbit for close to two weeks and were monitored to verify continuous operation.
For this mission, each smartphone is housed in a standard cubesat structure that measures about 4 in.2 Its smartphone acts as the satellite’s on-board computer. The smartphone’s sensors are used for attitude determination while the camera performs Earth observation. The off-the-shelf PhoneSats include many systems that are required for a satellite, such as fast processors, versatile operating systems (OSs), multiple miniature sensors, high-resolution cameras, Global Positioning System (GPS) receivers, and several radios.
These spacecraft are probably the lowest-cost satellites to ever be flown in space. NASA engineers kept total component cost for the three prototype PhoneSat satellites to between $3500 and $7000. In addition to using primarily commercial electronic hardware, they kept the design and mission objectives to a minimum. The mission hardware is the Google-HTC Nexus One smartphone, which runs the Android OS.
Some parts did need to be added to the smartphones, such as a larger, external lithium-ion battery bank. They also require a more powerful radio for the messages that they will send from space. The smartphones’ ability to send and receive calls and text messages was disabled for the mission.
