Balloon launch · November 23, 2014
A latex weather balloon carrying two Android phones, a keychain camera and five paper airplanes, released from the hills east of Milpitas. It climbed past the limit of its GPS to an estimated 105,000 to 115,000 feet, drifted southeast over the Central Valley, and came down in the Sierra foothills near Glennville, where the tracking phone was found five days later.
Altitude over time
Both phones’ GPS chips stop reporting altitude at a fixed ceiling: 18,174 m (59,626 ft) for the primary and 6,053 m (19,859 ft) for the secondary.
† Estimated, not measured. The primary phone’s GPS stops reporting at 18,174 m (59,626 ft), which it reached at 10:17 am. Below that, the balloon climbed at a nearly constant rate, as latex weather balloons do: a straight line fitted to the phone’s 44 readings from 9,000 m up gives 644 ft per minute (3.3 m/s), and the readings sit within about 30 m of it. Altitudes after 10:17 am follow that line. The phone kept recording until its battery ran out at 11:09 am, when the line puts the balloon at about 28,300 m (92,800 ft), still climbing. The burst itself was not recorded. Going by the climb rate and how fast the small parachute would have come down, it most likely burst between 105,000 and 115,000 ft (32,000–35,100 m), which on the same line would be between 11:28 am and 11:43 am.
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In the order they were taken
Photos that came out almost entirely white or black are left out.
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