The four-astronaut crew of Atlantis' STS-135 mission released the PicoSat into orbit via a spring ejection canister at 3:54 a.m. EDT (0754) Wednesday. The mini spacecraft is covered with solar panels to test new solar cell technology.
"We copy that, Houston," Atlantis' commander Chris Ferguson replied. "We'll call the deployment time MET [Mission Elapsed Time] 11 days 16:20."
PicoSat, officially named the Pico-Satellite Solar Cell test bed, is a small rectangular box about 5 inches by 5 inches by 10 inches, and weighs only 8 pounds (3.7 kg). It has its own solid rocket booster propulsion systems, communications capabilities, a GPS unit and solar cells for gathering energy.
After the small spacecraft is deployed into a low orbit at around 360 km, it will use multiple onboard megapixel cameras to take some last parting shots of shuttle Atlantis in orbit. These will be the last photos of a space shuttle ever taken from space. [Photos: NASA's Last Shuttle Mission In Pictures]
PicoSat is expected to operate on orbit for three to nine months. During that time it will also perform two experiments for the DoD.
One, called the Miniature Tracking Vehicle experiment, will test whether a nanosatellite like the PicoSat can serve as an orbiting reference point for ground tracking systems. The second, called Compact Total Electron Content Sensor, will monitor space weather and detect the density of the Earth's ionosphere.