Stratospheric Balloon Research Articles

Atmospheric Neutron Monitoring through Optical Fiber-Based Sensing

The potential of fiber-based sensors to monitor the fluence of atmospheric neutrons is evaluated through accelerated tests at the TRIUMF Neutron Facility (TNF) (BC, Canada), offering a flux approximatively 109 higher than the reference spectrum observed under standard conditions in New York City, USA. The radiation-induced attenuation (RIA) at 1625 nm of a phosphorus-doped radiation sensitive optical fiber is shown to linearly increase with neutron fluence, allowing an in situ and easy monitoring of the neutron flux and fluence at this facility. Furthermore, our experiments show that the fiber response remains sensitive to the ionization processes, at least up to a fluence of 7.1 × 1011 n cm−², as its radiation sensitivity coefficient (~3.36 dB km−1 Gy−1) under neutron exposure remains very similar to the one measured under X-rays (~3.8 dB km−1 Gy−1) at the same wavelength. The presented results open the way to the development of a point-like or even a distributed dosimeter for natural or man-made neutron-rich environments. The feasibility to measure the dose caused by the neutron exposure during stratospheric balloon experiments, or during outer space missions, is presented as a case study of a potential future application.

Improving Wind Forecasts in the Lower Stratosphere by Distilling an Analog Ensemble Into a Deep Neural Network

AbstractWe discuss improving forecasts of winds in the lower stratosphere using machine learning to postprocess the output of the European Centre for Medium‐Range Weather Forecasts (ECMWF) Integrated Forecast System. We postprocess global three‐dimensional predictions and demonstrate distilling the analog ensemble (AnEn) method into a deep neural network, which reduces postprocessing latency to near zero maintaining increased forecast skill. This approach reduces the error with respect to ECMWF high‐resolution deterministic prediction between 2–15% for wind speed and 15–25% for direction and is on par with ECMWF ensemble (ENS) forecast skill to hour 60. Verifying with Loon data from stratospheric balloons, AnEn has 20% lower error than ENS for wind speed and 15% for wind direction, despite significantly lower real‐time computational cost to ENS. Similar performance patterns are reported for probabilistic predictions, with larger improvements of AnEn with respect to ENS. We also demonstrate that AnEn generates a calibrated probabilistic forecast.

UV-Induced Nanoparticles-Formation, Properties and Their Potential Role in Origin of Life.

Inorganic nanoparticles might have played a vital role in the transition from inorganic chemistry to self-sustaining living systems. Such transition may have been triggered or controlled by processes requiring not only versatile catalysts but also suitable reaction surfaces. Here, experimental results showing that multicolor quantum dots might have been able to participate as catalysts in several specific and nonspecific reactions, relevant to the prebiotic chemistry are demonstrated. A very fast and easy UV-induced formation of ZnCd quantum dots (QDs) with a quantum yield of up to 47% was shown to occur 5 min after UV exposure of the solution containing Zn(II) and Cd(II) in the presence of a thiol capping agent. In addition to QDs formation, xanthine activity was observed in the solution. The role of solar radiation to induce ZnCd QDs formation was replicated during a stratospheric balloon flight.

The long duration cryogenic system of the OLIMPO balloon–borne experiment: Design and in–flight performance

We describe the design and in–flight performance of the cryostat and the self–contained 3He refrigerator for the OLIMPO balloon–borne experiment, a spectrophotometer to measure the Sunyaev–Zel’dovich effect in clusters of galaxies.The 3He refrigerator provides the 0.3 K operation temperature for the four arrays of kinetic inductance detectors working in 4 bands centered at 150, 250, 350 and 460 GHz. The cryostat provides the 1.65 K base temperature for the 3He refrigerator, and cools down the reimaging optics and the filters chain at about 2 K.The integrated system was designed for a hold time of about 15 days, to achieve the sensitivity required by the planned OLIMPO observations, and successfully operated during the first long–duration stratospheric flight of OLIMPO in July 2018.The cryostat features two tanks, one for liquid nitrogen and the other one for liquid helium. The long hold time has been achieved by means of custom stiff G10 fiberglass tubes support, which ensures low thermal conductivity and remarkable structural stiffness; multi–layer superinsulation, and a vapour cooled shield, all reducing the heat load on the liquid helium tank.The system was tested in the lab, with more than 15 days of unmanned operations, and then in the long duration balloon flight in the stratosphere. In both cases, the detector temperature was below 300 mK, with thermal stability better than ±0.5 mK.The system also operated successfully in the long duration stratospheric balloon flight.

First in situ UV profile across the UTLS accompanied by ozone measurement over the Tibetan Plateau

Ultraviolet radiation (UV) and ozone can greatly affect human health and the Earth's ecological environment. By deploying a UV radiometer aboard a stratospheric balloon released at Qaidam (QDM) during the Asian summer monsoon (ASM) period in 2019, we provided in situ measurement of the UV profiles from the surface to the upper troposphere and lower stratosphere over the Tibetan Plateau (TP), China, for the first time. Based on two in situ UV profiles accompanied by four ozonesonde measurements, this study exhibited detailed variations of downwelling UV and vertical ozone distributions over the TP during the ASM period. The UV differences between the surface and stratospheric balloon flight altitudes were 16.7, 15.8, 12.6 and 18.0 Wm−2 during the four ozonesonde launches. Due to the diurnal variations in photochemical production and the stratosphere-troposphere exchange, the integrated ozone columns below 30 km ranged from 184.4 to 221.6 DU from four ozonesonde measurements. A positive correlation between UV attenuation and ozone column was exhibited under low cloud cover and clear sky conditions. The results of this study are expected to improve our understanding of UV and ozone properties, as well as their potential effects on terrestrial ecosystems and living environments over this significant plateau.

Download by parachute: retrieval of assets from high altitude balloons

We present a publicly-available toolkit of flight-proven hardware and software to retrieve 5 TB of data or small physical samples from a stratospheric balloon platform. Before launch, a capsule is attached to the balloon, and rises with it. Upon remote command, the capsule is released and descends via parachute, continuously transmitting its location. Software to predict the trajectory can be used to select a safe but accessible landing site. We dropped two such capsules from the SUPERBIT telescope, in September 2019. The capsules took ∼37 minutes to descend from ∼30 km altitude. They drifted 32 km and 19 km horizontally, but landed within 300 m and 600 m of their predicted landing sites. We found them easily, and successfully recovered the data. We welcome interest from other balloon teams for whom the technology would be useful.

The introduction of supplemental oxygen for high altitude balloon flight.

The introduction of supplemental oxygen for high altitude balloon flight.

The first flight of the OLIMPO experiment: instrument performance

OLIMPO is a balloon-borne experiment aiming at spectroscopic measurements of the Sunyaev-Zel’dovich effect in clusters of galaxies. The instrument operates from the stratosphere, so that it can cover a wide frequency range (from ∼ 130 to ∼ 520 GHz in 4 bands), including frequencies which are not observable with ground-based instruments. OLIMPO is composed of a 2.6-m aperture telescope, a differential Fourier transform spectrometer and four arrays of lumped element kinetic inductance detectors operating at the temperature of 0.3 K. The payload was launched from the Longyearbyen airport (Svalbard Islands) on July 14th, 2018, and operated for 5 days, at an altitude of 38 km around the North Pole. We report the in-flight performance of the first lumped element kinetic inductance detector arrays ever flown onboard a stratospheric balloon.

High-Altitude Balloon-Based Sensor System Design and Implementation.

As a kind of large-scale unmanned aerial vehicle, a high-altitude balloon can carry a large load up to tens of kilometers in the near space for a long time, which brings a new way for the stratosphere atmospheric detection. In order to provide a suitable working environment for the near-space detection load, it is necessary to design a sensor system based on a high-altitude balloon, which is used to provide environmental temperature, height position, and attitude information, current working, and video surveillance. The high-altitude balloon-based sensor system designed in this paper had participated in the near-space flight experiment, whose total flight time was 30 h and 53 min, and the horizontal flight time was 28 h and 58 min crossing the day and night. The high-altitude balloon-based sensor system had withstood the severe environment of the near-space during the day and night, providing accurate temperature measurement, real-time altitude position and attitude data acquisition, reliable current monitoring, and comprehensive video surveillance. In the next three years, the high-altitude balloon-based sensor system developed in this paper will continue to participate in the experiment and provide support for more detection loads.

STATION KEEPING OF WIND DRIVEN STRATOSPHERIC BALLOON VIA PROPULSION UNIT

One of the most difficult problems in stratospheric balloon’s design is to keep the balloon’s geographic coordinates. Stratospheric wind speeds vary significantly both daily and throughout the year. Wind drag acting on the balloon should be manipulated to control the horizontal coordinates (longitude and latitude degree) of the stratospheric balloons. In this paper, propulsion unit is applied to a wind driven stratospheric balloon to keep balloon’s coordinate over flight area. The simulation was applied to a zero-pressure high altitude balloon using actual wind profile for the first time to control the horizontal movement of the balloon. In addition, required thrust power and some parameters effects on it have been investigated. The results indicate that propulsion unit would be helpful to manipulate the horizontal motion of the balloon and to achieve keeping the balloon’s geographic location.

2019 Elijah High Altitude Balloon Payload: Electronic Failure at Altitude, Applications of Turbulence and Sonification of Data

The 2019 WSGC Elijah High-Altitude Balloon Payload Fellowship focused on 4 high-altitude phenomena: Modular Payload Design, Applications of Air Turbulence (power generation and visualization), Electronic Behavior at Altitude, and Sonification of Atmospheric Data. Modular payload design focused on user-accessibility by creating friction-reducing rings in-between insulation and the instrumentation capsule. Height-adjustable, modular shelving was also constructed. Turbulence and Electronics project both suffered data loss during flight. However, post-flight lab analysis showed the power generation apparatus produced 96J – 120J and turbulence visualization’s potential to assist in calculating Eddie dissipation rates. Additionally, Electronic Behavior observed corona discharges across large electrical gaps near-vacuum pressures. Sonification of Data used computer algorithms to transcribe data relationships into music. The intent was to allow users to perceive data relationships and patterns aurally.

Infrasound and Gravity Waves Over the Andes Observed by a Pressure Sensor on Board a Stratospheric Balloon

AbstractThe study of infrasound (acoustic) and gravity waves sources and propagation in the atmosphere of a planet gives us precious insight on atmosphere dynamics, climate, and even internal structure. The implementation of modern pressure sensors with high rate sampling on stratospheric balloons is improving their study. We analyzed the data from the National Aeronautics and Space Administration Ultra Long Duration Balloon mission (16 May to 30 June 2016). Here, we focus on the balloon's transit of the Andes Mountains. We detected gravity waves that are associated to troposphere convective activity and mountain waves. An increase of the horizontal wavelengths from 50 to 70 km with increasing distance to the mountains is favoring the presence of mountain waves. We also report on the detection of infrasounds generated by the mountains in the 0.01–0.1 Hz range with a pressure amplitude increase by a factor 2 relative background signal. Besides, we characterized the decrease of microbaroms power when the balloon was flying away from the ocean coast. These observations suggest, in a way similar to microseisms for seismometers, that microbaroms are the main background noise sources recorded in the stratosphere even far from the ocean sources. Finally, we observed a broadband signal above the Andes, between 0.45 and 2 Hz, probably associated with a thunderstorm. The diversity of geophysical phenomena captured in less than a day of observation stresses the interest of high rate pressure sensors on board long‐duration balloon missions.

Operational Feasibility Study of High Altitude Balloon Platform based on the Wind Environment in South Korea

Naval helicopters flying at extremely low altitudes often face communication problems when the helicopter is located in the distance from the mother ship. Accordingly, new attention is being cast on the high altitude balloon (HAB) to solve this problem due to its cost-effectiveness and ability of rapid deployment to the battlefield. The balloon is one of a lighter-than-air vehicle that the blowing wind determines its speed, direction, and travel distance. Therefore, it is likely that seasonal changes in wind conditions will restrict the operation of the balloon. In this paper, the feasibility study of the balloon, which is regarded as a future communication relay platform, on the theater of operation of the Republic of Korea Navy the First Fleet was performed. The trends of the balloon trajectory for five years (2014 ~ 2018) with respect to seasonal wind variations were investigated employing the numerical trajectory prediction program. Simulated balloon trajectories of summer and winter showed considerable differences due to seasonal wind. Summer season was found that it has the most favorite flight environment for the balloon campaign. Upon reflecting on the simulation results, the HAB operating procedure, which capitalised on the Ulleungdo, was also suggested.

Instrumentation of Stratospheric Balloon Straps with Optical Fibre for Temperature and Strain Monitoring.

This article is devoted to the instrumentation, with optical fibres, of the straps holding the envelope of stratospheric balloons. This instrumentation is motivated in the first instance by the need to validate the numerical models used in the design of balloons. It must also be used to measure the temperature along the envelope in order to deduce the pressure field. It is shown at first that the optical fibres can be inserted inside a strap during its fabrication. Different kinds of insertion are considered, none of them perturb the industrial process. The instrumented straps were then submitted to thermal and mechanical tests and the distributed Brillouin frequency shifts were measured. We thus determined the type of insertion to be used according to the parameter (temperature or strain) to be measured and assessed the performance of the measurement chain.

Station-keeping control design of double balloon system based on horizontal region constraints

Stratospheric balloons can be used as a cost-effective platform for commercial and military applications. One of the technical challenges of balloon system is the station-keeping ability in the wind field. In order to realize station-keeping, a double-balloon system was provided in this paper. By adjusting the connecting rope length between main balloon with assistant balloon, double-balloon system uses different altitude wind layers to full advantages. A theoretical model which consists of atmospheric model, thermal model and dynamic model was proposed. A program was developed to simulate the performance of double-balloon system in real wind field. The effects of wind force acting on balloons, the assistant balloon motion properties and the double-balloon system station-keeping performance were investigated in detail. The results showed that the change of double-balloon system horizontal velocity direction over a short period of time is attributed to the forces pulse, the horizontal force acting on double-balloon system changes with the variation of the connecting rope length, which provides a possibility to retain the double-balloon system within a specific region. The double-balloon system provided in our study adjusts balloon system horizontal movement continuously and save more weight for effective payload, which has valuable reference in design of stratospheric balloons for station-keeping for a long time.

Implementation of a Low-Cost Flight Tracking System for High-Altitude Ballooning

High-altitude balloons (HABs) are typically tracked via Global Positioning System (GPS) data sent via real-time radio-based communication systems such as the Automatic Packet Reporting System (APRS). Prefabricated APRS-compatible tracker modules have made it trivial to transmit GPS coordinates and payload parameters in compliance with the requisite AX.25 protocol. However, in order to receive and track APRS signals, conventional methodologies call for the use of a very-high-frequency (VHF) receiver to demodulate signals transmitted on the APRS frequencies, along with a compatible antenna and custom methodology for visualizing the HAB’s location on a map. The entire assembly is typically costly, cumbersome, and may require an Internet connection in order to obtain real-time visualization of the HAB’s location. This paper describes a low-cost, handheld system based on open-source software that operates independently of an Internet connection. The miniaturized system is suited to tracking done either from a vehicle or on foot, and it is cost-effective enough to be within the means of nearly any HAB user. The paper also discusses preliminary test results and further applications.

Real data-based thermal environment definition for the ascent phase of Polar-Summer Long Duration Balloon missions from Esrange (Sweden)

Long Duration Balloon missions are key platforms for scientific research and space technology development. Thermal analyses of this kind of systems are crucial for the success of the mission. Even though the science is usually performed at float altitude, the ascent phase, usually non-operational, is where the extreme cold conditions occur, due to the convective effects caused by relative wind speed together with the low temperatures found in the tropopause, making this scenario a dimensioning case. In this paper, a thorough study of the thermal environmental conditions during the ascent is carried out, in particular winds, temperature, and radiative thermal loads have been obtained as a function of the altitude. The study is based on real data obtained from different sources, including atmospheric soundings, radar and satellite, and a meticulous statistical treatment. The study is focussed on one of the main stratospheric balloon launch sites in Europe, Esrange (Sweden), a center of the Swedish Space Corporation, and the analyses are performed for the summer period. However, the methodology can be extended to any other location and epoch. As an example, the convective effect of the horizontal winds on a plate has been studied, and the heat transfer during the ascent phase has been quantified. A subcooling of around 7 °C was found in this case, which make worth the dedicated analysis.

Engineering part of Payload box in High Altitude Balloon Experiment.

High-altitude balloons have long been used for experimental access to both the lower and upper atmosphere, including the troposphere and stratosphere. On this poster, I am describing the design and the engineering part of the payload box with Pocket lab device in High Altitude Balloon Experiment.

Temporal and Spatial Variations of Cosmogenic Radionuclide Production Rates in Chondrites During Their Passage Through the Inner Heliosphere

To study radiation environment in the interplanetary space, cosmogenic radionuclides in meteorites, the production rates of which are in direct proportionality to the intensity of cosmic rays, are used. The contents of cosmogenic radionuclides of different half-lives T1/2, measured in 42 stony meteorites (chondrites) having sequentially fallen onto the Earth during the period of 1959–2016, are analyzed. They are accumulated by the galactic cosmic rays (GCRs) along the orbits of the chondrites before their falls onto the Earth at some average heliocentric distances, depending on the size of the chondrite orbit and on T1/2 of the radionuclide. The comparison with the calculated production rates of radionuclides in the identical chondrites for isotropic irradiation by the GCRs at ~ 1 AU is demonstrated. The calculations are based on the stratospheric balloon monthly data on the GCR intensity [1] for the periods of accumulation of each radionuclide in each chondrite. The dependence of production rates of the radionuclides of different half-lives upon the GCR variations in the heliosphere is studied. The obtained long set of homogeneous data on cosmogenic radionuclide production rates in consecutively fallen chondrites provides the unique information on the space-time continuum of the cosmogenic radionuclide production rates and their variations over a long-time scale, which could be useful in the correlative analyses of processes in the inner heliosphere and, thus, in the forecast of radiation situation, which is important for the predicted manned flights.

High altitude balloon checking our weather forecast

It talks about what we planned to do with the pocket lab and what we have tried and the results we got from the project. We also talk about the purpose of this project and what this pocket lab could help was what we wanted.