Rotation Mitigation and OCCAMS + Tungsten Flight Termination for Eclipse Balloon Missions

Stack rotation is a nemesis for many ballooning experiments, especially photography when trying to keep a specific target in view such as the Moon’s shadow (or the Sun itself) on eclipse flights. Ascending weather balloons tend to slow or even stop rotating once in the stratosphere and out of most cross winds. However payload stacks can continue to rotate with respect to the balloon right up to burst, especially if attached to the balloon neck by just a single main line. Our passive “rotation mitigation” device attaches directly to the neck of the balloon and runs four parallel lines separated by 6 inches from the balloon neck down to the payload stack, significantly diminishing stack rotation with respect to the balloon, especially at high altitudes. This arrangement complicates the placement of the parachute, but we have successfully deployed parachutes from a hook on the side of the upper-most payload box. This also complicates the placement of a flight-termination line-cutter, be that Montana’s “OCCAMS” razor cutter or something like a Tungsten hot-wire cutter. We have developed a compact payload box to enclose both an OCCAMS razor cutter and a Tungsten hot-wire cutter, both of which can independently release the multiple lines of our rotation mitigation device. We can fire the OCCAMS by XBee commands relayed through our RFD 900 payload, as an alternative to the Iridium text-message system. The Tungsten cutter can be fired by XBee command, by timer, or by autonomous GPS-sensor-based decision making

Eclipse-Ballooning 2017: The U of MN – Twin Cities Experience

The stratospheric ballooning team at the U of MN – Twin Cities started working on eclipse-ballooning in the fall of 2013, even before the Montana Space Grant announced their plan to organize a national Eclipse Ballooning Project. Our team promptly signed up to assist their effort, and have been heavily involved ever since. This presentation will discuss our eclipse-ballooning efforts and progress over the past 4 years. Our experiences include experimenting with a GoPro-based video-telemetry system (which ultimately was not as successful as Montana’s Raspberry-Pi-based system), adopting (then helping test, modify, and teach other teams to learn to use) the Montana telemetry system, practicing with up-range and down-range ground station placement, developing and testing passive anti-rotation devices and active camera-pointing devices to improve video quality, landing two eclipse-telemetry systems in Minnesota lakes one week before the eclipse (ouch!), flying five balloon stacks during the eclipse from near Grand Island, NE, and organizing/hosting AHAC 2017. We will also discuss ways in which we have already begun to use the telemetry equipment for non-eclipse balloon missions. The eclipse project has greatly expanded our HAB network and ballooning capabilities in multiple different directions, and will continue to strongly influence our stratospheric ballooning program for years to come

Rotation Mitigation and OCCAMS + Tungsten Flight Termination for Eclipse Balloon Missions

Stack rotation is a nemesis for many ballooning experiments, especially photography when trying to keep a specific target in view such as the Moon’s shadow (or the Sun itself) on eclipse flights. Ascending weather balloons tend to slow or even stop rotating once in the stratosphere and out of most cross winds. However payload stacks can continue to rotate with respect to the balloon right up to burst, especially if attached to the balloon neck by just a single main line. Our passive “rotation mitigation” device attaches directly to the neck of the balloon and runs four parallel lines separated by 6 inches from the balloon neck down to the payload stack, significantly diminishing stack rotation with respect to the balloon, especially at high altitudes. This arrangement complicates the placement of the parachute, but we have successfully deployed parachutes from a hook on the side of the upper-most payload box. This also complicates the placement of a flight-termination line-cutter, be that Montana’s “OCCAMS” razor cutter or something like a Tungsten hot-wire cutter. We have developed a compact payload box to enclose both an OCCAMS razor cutter and a Tungsten hot-wire cutter, both of which can independently release the multiple lines of our rotation mitigation device. We can fire the OCCAMS by XBee commands relayed through our RFD 900 payload, as an alternative to the Iridium text-message system. The Tungsten cutter can be fired by XBee command, by timer, or by autonomous GPS-sensor-based decision making

Eclipse-Ballooning 2017: The U of MN – Twin Cities Experience

The stratospheric ballooning team at the U of MN – Twin Cities started working on eclipse-ballooning in the fall of 2013, even before the Montana Space Grant announced their plan to organize a national Eclipse Ballooning Project. Our team promptly signed up to assist their effort, and have been heavily involved ever since. This presentation will discuss our eclipse-ballooning efforts and progress over the past 4 years. Our experiences include experimenting with a GoPro-based video-telemetry system (which ultimately was not as successful as Montana’s Raspberry-Pi-based system), adopting (then helping test, modify, and teach other teams to learn to use) the Montana telemetry system, practicing with up-range and down-range ground station placement, developing and testing passive anti-rotation devices and active camera-pointing devices to improve video quality, landing two eclipse-telemetry systems in Minnesota lakes one week before the eclipse (ouch!), flying five balloon stacks during the eclipse from near Grand Island, NE, and organizing/hosting AHAC 2017. We will also discuss ways in which we have already begun to use the telemetry equipment for non-eclipse balloon missions. The eclipse project has greatly expanded our HAB network and ballooning capabilities in multiple different directions, and will continue to strongly influence our stratospheric ballooning program for years to come