Implementation of Simultaneous Multi-Streaming of Live Solar Eclipse Video via 5.8 GHz AirMax

For the 2017 solar eclipse ballooning, we have developed a video payload that can simultaneously live-stream multiple videos via a single 5.8 GHz wireless link through a Ubiquiti Rocket M5 modem. In this paper, we describe our approach to multiplex multiple video streams into a single data stream that a 5.8 GHz wireless modem can transport to the ground station. Various key factors are described to properly configure the Raspberry Pis and optimize the transmission from an M5 modem on the video payload over the 5.8 GHz link while ensuring adequate range and acceptable video quality received at the ground station. A screenshot of the multi-video streaming is provided as an example to justify a successful operation of our video payload.

Incorporating Redundant Systems to Capture the Kentucky Money Shot

The Kentucky Eclipse Ballooning Project began in early 2015 when students and faculty from The University of Kentucky attended the NASA Marshall Space Flight Center BalloonSat Workshop in Huntsville, Alabama. The students accelerated their preparations after the Eclipse Ballooning Project Workshop hosted in Bozeman, Montana where they built and learned systems designed by Montana Space Grant. In 2016, the students began a sequence of 10 balloon launches in preparation for the total solar eclipse on August 21, 2017. In the early stages of this project, University of Kentucky students set the goal to capture footage of a separate high-altitude weather balloon in front of the solar eclipse, an image dubbed “The Kentucky Money Shot.” After establishing that goal, students began working on approaches and designs to capture this picture with one overarching theme: redundancy. Every aspect of the project from the number of balloons and imaging systems to tracking systems and launch procedures were designed with redundant aspects and through collaboration among the payload, ground station, launch, and mission control teams. The short time window of eclipse totality, 2 minutes 28 seconds, motivated design iterations throughout the progressive practice launches and ground tests including launching two balloons simultaneously, streaming and storing footage of the flight from multiple cameras, and using SPOT Trackers and Iridium systems as multiple tracking approaches. All of these practices and tests led to flying the final redundant designs on August 21st, 2017 to successfully capture “The Kentucky Money Shot”.

Thermal Wake Studies During the August 21st 2017 Total Solar Eclipse

A thermal wake occurs when a high altitude balloon (HAB) influences and changes the surrounding ambient atmospheric temperature of the air through which it passes. This effect warms the air below the balloon to greater than the ambient temperatures during daytime flights, and cooler than ambient temperatures during nighttime flights. The total solar eclipse of August 21st, 2017, provided us with an opportunity to study these balloon induced temperature transitions from daytime, to eclipsed induced night conditions over the scale of a single flight. To measure these transitions, St. Catherine University and the University of Minnesota, Morris, flew over 40 temperature sensors suspended beneath weather balloons ascending within the path of totality. Stratospheric temperature data collected during the eclipse show evidence of both daytime and nighttime wake temperature profiles.

Computational Fluid Dynamics Study of Balloon System Tethered to a Stratosail

In this paper, we present a numerical study of a stratospheric balloon system tethered to a passive device, known as the Stratosail, for station-keeping operation. For scientific applications, stratospheric balloons that operate at altitudes between 15 and 20 km will need to maintain station over a fixed point above the earth for a prescribed period of time. This is a challenging problem due to the limitation of payloads and lack of an energy source. The present study uses computational fluid dynamics (CFD) simulations to analyze the drift velocity of such a balloon-Stratosail system under typical wind conditions in the stratosphere. The Stratosail is attached below the super-pressure helium balloon via a long and thin tether about 10 to 15 km below the balloon, providing a drag force to alter the flight path of the balloon. Its operation depends on the natural differences in the wind speed and wind direction at different altitudes in the atmosphere that act on the balloon and the Stratosail (spaced far apart by 10km to 15 km). In this study, we calculated the drag forces on the balloon and Stratosail for typical wind speeds at various altitudes in the stratosphere. The tether was also modelled as a cable joining the balloon and sail. With this model, the drift velocity of the system was calculated for various altitudes and the angle of attack of the sail.

The Louisiana Space Consortium Student Sounding Balloon Program

Since the fall of 2003 the Louisiana Aerospace Catalyst Experiences for Students (LaACES) program has been providing university students a two semester project that culminates with the flight of a scientific balloon experiment. During the first semester students complete the Student Ballooning Course (SBC) which teaches basic skills necessary to develop a working scientific payload. The SBC consists of a series of lectures and activities providing instruction in electronics, programming, project management, balloon payload design, and introductory circuit assembly. The SBC introduces the BalloonSat, a sub-assembly designed at LSU for LaACES which contains a microcontroller, real-time clock and a four channel analog-to-digital converter. The second semester is spent on the design, development, testing and calibration of the payloads. Upon completion of the Flight Readiness Review, students travel to the NASA Columbia Scientific Balloon Facility (CSBF) in Palestine, Texas for integration, launch, recovery and science presentations. A flight capable Automatic Packet Reporting System (APRS) radio beacon armed with GPS and command capable cut down was developed to track the balloon during flight and to cut-down the payloads. Tracking vehicles are outfitted with radios tuned to APRS frequency and laptops displaying maps of the payload location. Here we describe LaACES; program development, tools and technologies, implementation, program, management issues and flight experiences.

The Regener-Pfotzer Maximum During a Total Solar Eclipse

The Regener-Pfotzer (RP) maximum is the altitude at which cosmic radiation intensity is the greatest. A decrease of the altitude of the interaction layer, assumed to be measured by the RP maximum, has been suggested to account for a reduction in the secondary cosmic ray flux measured at the surface of the Earth during a total solar eclipse. To investigate this suggestion, high altitude cosmic radiation was measured using Geiger Mueller (GM) counters carried beneath weather balloons both before and during the total solar eclipse on 21 August 2017. The 19 and 20 August 2017 omnidirectional RP maxima occurred at an average altitude of 20.2 km ± 0.9 km. During the eclipse of 21 August 2017 the omnidirectional RP maxima occurred at an altitude of 20.4 km ± 0.8 km. The 19 and 20 August 2017 vertical coincidence RP maxima occurred at an altitude of 18.3 km ± 1.0 km. During the eclipse the vertical coincidence RP maxima occurred at 18.0 km ± 1.0 km. Our results do not show any decrease in the altitude of either the omnidirectional or the vertical coincidence RP maximum outside the range of our measurements before the eclipse.

Directional Camera Control on High Altitude Balloons

The research reported in this paper examined the design and control of a gimbal for solar eclipse tracking and video recording. The gimbal design required 3 axes of rotation to allow for a full range of motion. Utilizing individual brushless motors for each of the axes ensures minimum rotational requirements on each axes. In controlling the gimbal, both a mathematical and visual method was utilized. The mathematical method is a modeled version of what is currently used for solar array pointing. The visual method looks at where the position of the sun is within the image and determines what angle changes are required. Utilizing a combination of these methods helps to eliminate error that accumulates within the onboard gyros due to the erratic behavior of balloon motion during flight. Elimination of this error ensures accurate video recording of the solar eclipse.

Tropospheric Sounding with Low-Cost Particulate Matter Sensors

The high-altitude balloon (HAB) platform has allowed scientists to measure vertical profiles in the atmosphere at a relatively low cost. The current project combines the HAB platform with low-cost air quality sensors that measure particulate matter (PM). PM is detrimental to human health and can exacerbate asthma. In the atmosphere, PM can affect cloud formation and also radiative transfer, which links emissions of PM to climate change. Therefore, understanding and controlling PM emissions is vital to air quality and climate change. In agricultural regions, several practices produce significant PM emissions. Tilling can release PM in the form of dust, especially under arid conditions. The burning of crop residue is also a common practice practice that releases PM in the form of partially combusted organics (soot). The ultimate goal of this project is to use low-cost PM sensors and HAB to assess PM sources from agricultural regions using citizen scientists. The current presentation evaluates the performance of two different PM sensors over flights conducted during the summer of 2017.

Active Heading Control Platform for Instruments Flown on High Altitude Balloons

Experiments flown on high-altitude balloons are typically free to spin without any control or information collected on the payload orientation during flight, limiting the scope of experiments that can be performed. Projects that include targeting (i.e. imaging the 2017 solar eclipse) have at best a random chance of succeeding, while video footage is often hard to watch due to high payload rotation rates. While passive stabilization reduces the rotation rate, active pointing control is necessary for continuous target acquisition. Here we discuss a project built by students at Wright College called the Controlled Heading Automation Device (CHAD) that actively controls the heading of other instruments (i.e. cameras) and has been proven to work in flight. This project is open-source, 3D printable, made from cheap DIY electronics, and has been made available online (http://physi.cz/chad) so the high-altitude ballooning community can create, use, and adapt it to their own projects. We show how to create an attitude and heading reference system (AHRS) that can be used to continuously record payload orientation, which can supplement experiments where pointing information is needed. We then show how to have CHAD use the AHRS to automatically control the heading of other instruments in real-time without any other inputs.