MIT Technology Review  November 14, 2018 The current balloons shift with the wind and can only stay in one area for a few days at a time. DARPA is currently testing a wind sensor that could allow devices in its Adaptable Lighter-Than-Air (ALTA) balloon program to spot wind speed and direction from a great distance and then make the necessary adjustments to stay in one spot. DARPA has been working on ALTA for some time, but its existence was only revealed in September. ALTA will operate even higher than Google’s Loon  at 75,000 to 90,000 feet (22,900 to 27,400 meters […]