Improving the “Active Heading Control Platform” (CHAD) for Active Experiment Pointing During Stratospheric Balloon Flights

Payloads carried into the stratosphere using weather balloons typically spin and sway during ascent, limiting the types of experiments that can be performed. This project aimed to improve the functionality and performance of the Arduino-controlled active anti-rotation camera platform called CHAD (Controlled Heading Automation Device) that was reported upon at AHAC 2016 by Andrew Kruger from Wilbur Wright College in Chicago. The CHAD device senses its orientation using a magnetometer and an inertial measurement unit, then counters rotation by turning its main shaft with a stepper motor so as to hold fixed the absolute heading of the attached experiment (such as a video camera). The goals of this project were to make CHAD more low-temperature tolerant, to add the capability to adjust the heading in flight by radio command, and to add on-board logging of sensor data, stepper motor commands, actual orientation (independent from what the stepper motor was told to do), and all radio communications. This log was valuable for post-flight analysis if the unit did not hold its heading as effectively as desired. Some thermal issues were identified and addressed. The stepper motor was found to be powerful enough to control the heading of a full video-telemetry system, not just a bare video camera. The implementation of an in-flight-reset command proved valuable. A shaft-rotation encoder was added to assist in knowing orientation independently from the stepper motor commands. Although significant progress has been made, in-flight performance of the modified CHAD device remains somewhat inconsistent in stratospheric conditions

Development of a Multi-Cut Payload for use in Stratospheric Ballooning Missions

The ability to cut strings (AKA lines) during stratospheric ballooning missions has a wide variety of uses including, but not limited to, (a) flight termination (i.e. cutting payloads away from the main balloon), (b) cutting away excess lift balloon(s) to slow ascent rate (and possibly achieve float), (c) cutting away ballast weights to slow descent rate or increase ascent rate, (d) cutting away burst balloon(s) on descent to avoid parachute entanglement, and (e) cutting away payloads which are intended to return to the ground independently, for experimental purposes. We report on the development of a “multi-cut” payload box that uses an Arduino microcontroller that can control the cutting of multiple strings in arbitrary order at arbitrary points during a mission, expanding our options for stratospheric ballooning operations. For example, this device may be used during the solar eclipse of August 2017 to drop a timed-series of independently-recovered Geiger counter payloads from a stratospheric balloon stack to characterize changes to the Pfotzer maximum as the Moon’s shadow passes

Genetic Characterization of the Soybean Nested Association Mapping Population

A set of nested association mapping (NAM) families was developed by crossing 40 diverse soybean [Glycine max (L.) Merr.] genotypes to the common cultivar. The 41 parents were deeply sequenced for SNP discovery. Based on the polymorphism of the single-nucleotide polymorphisms (SNPs) and other selection criteria, a set of SNPs was selected to be included in the SoyNAM6K BeadChip for genotyping the parents and 5600 RILs from the 40 families. Analysis of the SNP profiles of the RILs showed a low average recombination rate. We constructed genetic linkage maps for each family and a composite linkage map based on recombinant inbred lines (RILs) across the families and identified and annotated 525,772 high confidence SNPs that were used to impute the SNP alleles in the RILs. The segregation distortion in most families significantly favored the alleles from the female parent, and there was no significant difference of residual heterozygosity in the euchromatic vs. heterochromatic regions. The genotypic datasets for the RILs and parents are publicly available and are anticipated to be useful to map quantitative trait loci (QTL) controlling important traits in soybean

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

Improving the “Active Heading Control Platform” (CHAD) for Active Experiment Pointing During Stratospheric Balloon Flights

Payloads carried into the stratosphere using weather balloons typically spin and sway during ascent, limiting the types of experiments that can be performed. This project aimed to improve the functionality and performance of the Arduino-controlled active anti-rotation camera platform called CHAD (Controlled Heading Automation Device) that was reported upon at AHAC 2016 by Andrew Kruger from Wilbur Wright College in Chicago. The CHAD device senses its orientation using a magnetometer and an inertial measurement unit, then counters rotation by turning its main shaft with a stepper motor so as to hold fixed the absolute heading of the attached experiment (such as a video camera). The goals of this project were to make CHAD more low-temperature tolerant, to add the capability to adjust the heading in flight by radio command, and to add on-board logging of sensor data, stepper motor commands, actual orientation (independent from what the stepper motor was told to do), and all radio communications. This log was valuable for post-flight analysis if the unit did not hold its heading as effectively as desired. Some thermal issues were identified and addressed. The stepper motor was found to be powerful enough to control the heading of a full video-telemetry system, not just a bare video camera. The implementation of an in-flight-reset command proved valuable. A shaft-rotation encoder was added to assist in knowing orientation independently from the stepper motor commands. Although significant progress has been made, in-flight performance of the modified CHAD device remains somewhat inconsistent in stratospheric conditions

Development of a Multi-Cut Payload for use in Stratospheric Ballooning Missions

The ability to cut strings (AKA lines) during stratospheric ballooning missions has a wide variety of uses including, but not limited to, (a) flight termination (i.e. cutting payloads away from the main balloon), (b) cutting away excess lift balloon(s) to slow ascent rate (and possibly achieve float), (c) cutting away ballast weights to slow descent rate or increase ascent rate, (d) cutting away burst balloon(s) on descent to avoid parachute entanglement, and (e) cutting away payloads which are intended to return to the ground independently, for experimental purposes. We report on the development of a “multi-cut” payload box that uses an Arduino microcontroller that can control the cutting of multiple strings in arbitrary order at arbitrary points during a mission, expanding our options for stratospheric ballooning operations. For example, this device may be used during the solar eclipse of August 2017 to drop a timed-series of independently-recovered Geiger counter payloads from a stratospheric balloon stack to characterize changes to the Pfotzer maximum as the Moon’s shadow passes

Genetic Characterization of the Soybean Nested Association Mapping Population

A set of nested association mapping (NAM) families was developed by crossing 40 diverse soybean [Glycine max (L.) Merr.] genotypes to the common cultivar. The 41 parents were deeply sequenced for SNP discovery. Based on the polymorphism of the single-nucleotide polymorphisms (SNPs) and other selection criteria, a set of SNPs was selected to be included in the SoyNAM6K BeadChip for genotyping the parents and 5600 RILs from the 40 families. Analysis of the SNP profiles of the RILs showed a low average recombination rate. We constructed genetic linkage maps for each family and a composite linkage map based on recombinant inbred lines (RILs) across the families and identified and annotated 525,772 high confidence SNPs that were used to impute the SNP alleles in the RILs. The segregation distortion in most families significantly favored the alleles from the female parent, and there was no significant difference of residual heterozygosity in the euchromatic vs. heterochromatic regions. The genotypic datasets for the RILs and parents are publicly available and are anticipated to be useful to map quantitative trait loci (QTL) controlling important traits in soybean