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These days, much is made of applications that run in the metaphorical cloud. Well, here's an example of hardware and software that soared through the clouds, both real and metaphorical. On March 4, the ASTRA 7, a stratospheric gas balloon carrying a mobile phone running the Windows Phone 7 operating system, was launched from the Cotswolds in west-central England. The hardy phone made its way through the real clouds and into the stratosphere, recording and sending location data that was processed through the virtual cloud of Windows Azure. Part of the University of Southampton's ASTRA (Atmospheric Science Through Robotic Aircraft) initiative, the launch was designed to test the capabilities of the Windows 7 mobile computing platform in capturing, analyzing, and transmitting location data from unmanned vehicles in the upper atmosphere.
The phone's logger application included a "hunter mode," which allowed ASTRA staff on the ground to track the payload during its flight, thus enabling its recovery. The application uses Bing Maps to display the location of the balloon payload, the hunter's phone, the locations of the other hunters, as well as the predicted landing location, which was constantly re-computed in the cloud by Windows Azure as new location reports beamed down from the on-board phone.
The ASTRA 7 reached a maximum altitude of 18,237 meters during a flight of 1 hour 16 minutes, soaring deep into the stratosphere, where the ambient pressure was less than 10 percent of its sea level value and the temperature dropped to -58 C. The maximum speed reached by ASTRA 7 was approximately 145 kilometers per hour, logged at an altitude of 10.1 kilometers as the balloon traversed the jet stream. ASTRA 7 landed about 75 kilometers downrange—very close to the pre-flight prediction based on the ASTRA balloon flight simulation model. ASTRA 7 also took more than 1,200 photos during its flight, a small selection of which are included in this blog.
The phone and the rest of the equipment were protected by a high-grade cell-foam enclosure to ensure the reliable operation of the on-board electronics in the extreme environmental conditions of the upper atmosphere. The enclosure was manufactured by using a computer-controlled laser cutter at the university's Engineering Design and Manufacturing Centre. As part of the payload bay's development process, the ASTRA team tested the foam enclosure in a vacuum chamber to ensure that its mechanical properties would be satisfactory in the extremely low-pressure environment of the stratosphere.
On March 8, ASTRA launched a longer flight to see how the technology would cope with more prolonged exposure to stratospheric conditions. The payload, consisting of a Windows Phone 7, battery, and camera, remained airborne for approximately 2 hours 40 minutes, covering about 110 kilometers in the process.
ASTRA scientists are extremely pleased with the performance of the Windows 7 package, which fits perfectly with the initiative's goal of developing and testing platforms capable of delivering scientific instruments via unmanned vehicles to altitudes ranging from the planetary boundary layer to the upper stratosphere. Dr. András Sóbester, leader of the ASTRA initiative, summed it up nicely: "We are excited that this constitutes a unique opportunity to collect important data that will give new insight into how the upper atmosphere affects Earth's climate and environment, using affordable technology."
—Geoff Hughes, Academic Strategy Advisor, Microsoft UK Developer Platform Evangelism