Balloon Flights Research Articles

Comparisons of temperature, pressure and humidity measurements by balloon-borne radiosondes and frost point hygrometers during MOHAVE-2009

Abstract. We compare coincident, in situ, balloon-borne measurements of temperature (T) and pressure (P) by two radiosondes (Vaisala RS92, Intermet iMet-1-RSB) and similar measurements of relative humidity (RH) by RS92 sondes and frost point hygrometers. Data from a total of 28 balloon flights with at least one pair of radiosondes are analyzed in 1-km altitude bins to quantify measurement differences between the sonde sensors and how they vary with altitude. Each comparison (T, P, RH) exposes several profiles of anomalously large measurement differences. Measurement difference statistics, calculated with and without the anomalous profiles, are compared to uncertainties quoted by the radiosonde manufacturers. Excluding seven anomalous profiles, T differences between 19 pairs of RS92 and iMet sondes exceed their measurement uncertainty limits (2 σ) 31% of the time and reveal a statistically significant, altitude-independent bias of 0.5 ± 0.2 °C. Similarly, RS92-iMet P differences in 22 non-anomalous profiles exceed their uncertainty limits 23% of the time, with a disproportionate 83% of the excessive P differences at altitudes >16 km. The RS92-iMet pressure differences increase smoothly from −0.6 hPa near the surface to 0.8 hPa above 25 km. Temperature and P differences between all 14 pairs of RS92 sondes exceed manufacturer-quoted, reproducibility limits (σ) 28% and 11% of the time, respectively. About 95% of the excessive T differences are eliminated when 5 anomalous RS92-RS92 profiles are excluded. Only 5% of RH measurement differences between 14 pairs of RS92 sondes exceed the manufacturer's measurement reproducibility limit (σ). RH measurements by RS92 sondes are also compared to RH values calculated from frost point hygrometer measurements and coincident T measurements by the radiosondes. The influences of RS92-iMet Tand P differences on RH values and water vapor mixing ratios calculated from frost point hygrometer measurements are examined.

In Flight SEU/MCU Sensitivity of Commercial Nanometric SRAMs: Operational Estimations

A method and the corresponding platform devoted to operational SEE-rate prediction are presented and illustrated by experimental results. Predicted error-rates are in well agreement with results issued from the activation of an SRAM platform, in 90 nm technology node, on board stratospheric balloons flights. Direct ionization of protons is investigated for a 65 SRAM memory virtually boarded on the balloon flight.

Evaluation of AIS reception in Arctic regions from space by using a stratospheric balloon flight

ABSTRACTDue to the increased melting season in the arctic regions, especially in the seas surrounding Greenland, there has been an increased interest in utilising these waterways, both as an efficient transport route and an attractive leisure destination. However, with heavier traffic comes an increased risk of accidents. Due to the immense size and poor infrastructure of Greenland, it is not feasible to deploy ground based ship monitoring stations throughout the Greenland coastline. Thus the only feasible solution is to perform such surveillance from space. In this paper it is shown how it is possible to receive transmissions from the Automatic Identification System (AIS) from space and the quality of the received AIS signal is analysed. To validate the proposed theory, a field study, utilising a prototype of AAUSAT3, the third satellite from Aalborg University, was performed using a stratospheric balloon flight in the northern part of Sweden and Finland during the autumn of 2009. The analysis finds that, assuming a similar ship distribution as in the Barents Sea, it is feasible to monitor the ship traffic around Greenland from space with a satisfactory result.

Flight performance of an advanced CZT imaging detector in a balloon-borne wide-field hard X-ray telescope—ProtoEXIST1

We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes. The CZT detector plane in ProtoEXIST1 consists of an 8 x 8 array of closely tiled 2 cm x 2 cm x 0.5 cm thick pixellated CZT crystals, each with 8 x 8 pixels, covering a 256 cm^2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30 - 600 keV band for imaging, allowing a fully coded field of view of 9 Deg x 9 Deg with an angular resolution of 20 arcmin. To reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. On the back side, a 26 cm x 26 cm x 2 cm CsI(Na) active shield provides signals to tag charged particle induced events as well as >~ 100 keV background photons from below. The flight duration was only about 7.5 hours due to strong winds (60 knots) at float altitude (38-39 km). Throughout the flight, the CZT detector performed excellently. The telescope observed Cyg X-1 for ~ 1 hour at the end of the flight. Despite a few problems with the pointing and aspect systems that caused the telescope to track about 6.4 deg off the target, the analysis of the Cyg X-1 data revealed an X-ray source at 7.2 sigma in the 30-100 keV energy band at the expected location from the optical images taken by the onboard daytime star camera. The success of this first flight is very encouraging for the future development of the advanced CZT imaging detectors (ProtoEXIST2, with 0.6 mm pixels).

THE AFCRL LUNAR AND PLANETARY RESEARCH BRANCH

The Lunar and Planetary research program led by Dr John (Jack) Salisbury in the 1960s at the United States Air Force Cambridge Research Laboratories (AFCRL) investigated the surface characteristics of Solar System bodies. The Branch was one of the first groups to measure the infrared spectra of likely surface materials in the laboratory under appropriate vacuum and temperature conditions. The spectral atlases created from the results were then compared to photometric and spectral measurements obtained from ground- and balloon-based telescopes to infer the mineral compositions and physical conditions of the regoliths of the Moon, Mars and asteroids. Starting from scratch, the Branch initially sponsored observations of other groups while its in-house facilities were being constructed. The earliest contracted efforts include the spatially-resolved mapping of the Moon in the first half of the 1960s by Richard W. Shorthill and John W. Saari of the Boeing Scientific Research Laboratories in Seattle. This effort ultimately produced isophotal and isothermal contour maps of the Moon during a lunation and timeresolved thermal images of the eclipsed Moon. The Branch also sponsored probe rocket-based experiments flown by Riccardo Giacconi and his group at American Science and Engineering Inc. that produced the first observations of X-ray stars in 1962 and later the first interferometric measurement of the ozone and CO2 emission in the upper atmosphere. The Branch also made early use of balloon-based measurements. This was a singular set of experiments, as these observations are among the very few mid-infrared astronomical measurements obtained from a balloon platform. Notable results of the AFCRL balloon flights were the mid-infrared spectra of the spatially-resolved Moon obtained with the University of Denver mid-infrared spectrometer on the Branch's balloon-borne 61-cm telescope during a 1968 flight. These observations remain among the best available. Salisbury also funded John Strong at the Johns Hopkins University for several near-infrared experiments which created a bit of a stir by detecting water vapor and ice high in the atmosphere of Venus. Once lunar geology transitioned from remote sensing to hands-on geology with the lunar landings, the Branch turned its attention to quantifying the thermal spectral emission from planets for their use as possible infrared calibration sources. The Branch and its research were phased out in 1976 when the program was terminated with the reorganization of AFCRL into the Air Force Geophysics Laboratory (AFGL).

Searching for TeV cosmic electrons with the CREST experiment

The Cosmic Ray Electron Synchrotron Telescope (CREST) high-altitude balloon experiment is a pathfinding effort to detect for the first time multi-TeV cosmic-ray electrons. Such would be the markers of nearby cosmic accelerators, as energetic electrons from distant Galactic sources are expected to be depleted by radiative losses during interstellar transport. Electrons will be detected indirectly by the characteristic signature of their geomagnetic synchrotron losses, in the form of a burst of coaligned x-ray photons intersecting the plane of the instrument. Since the primary electron itself need not traverse the payload, an effective detection area is achieved that is several times the nominal 6.4 m 2 instrument. The payload is composed of an array of 1024 BaF2 crystals surrounded by a set of veto scintillator detectors. A long-duration balloon flight in Antarctica is planned for the 2011-12 season.

The TRACER instrument: A balloon-borne cosmic-ray detector

We describe a large-area detector for measurements of the intensity of cosmic-ray nuclei in balloon-borne exposures. In order to observe individual nuclei at very high energies, the instrument employs transition radiation detectors (TRD) whose energy response extends well beyond 104 GeV amu−1. The TR measurement is performed with arrays of single-wire proportional tubes interleaved with plastic-fiber radiators. An additional energy determination comes from the specific ionization in gas and its relativistic rise which is also measured with proportional tubes. The tubes also determine the trajectory of each cosmic-ray nucleus with mm-resolution. In total, nearly 1600 tubes are used. The instrument is triggered by large-area plastic scintillators. The scintillators, together with acrylic Cherenkov counters, also determine the nuclear charge Z of each cosmic-ray particle, measure the energy in the GeV amu−1 region, and discriminate against low-energy background. We describe the details of this detector system, and discuss its performance in three high-altitude balloon flights, including two long-duration flights in 2003 and 2006 at Antarctic and Arctic latitudes, respectively. Scientific results from these flights are summarized, and possible future developments are reviewed.

INTERPRETATION OF THE ARCADE 2 ABSOLUTE SKY BRIGHTNESS MEASUREMENT

We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon flight of the ARCADE 2 instrument, along with previous measurements at other frequencies, to constrain models of extragalactic emission. Such emission is a combination of the cosmic microwave background (CMB) monopole, Galactic foreground emission, the integrated contribution of radio emission from external galaxies, any spectral distortions present in the CMB, and any other extragalactic source. After removal of estimates of foreground emission from our own Galaxy, and an estimated contribution of external galaxies, we present fits to a combination of the flat-spectrum CMB and potential spectral distortions in the CMB. We find 2σ upper limits to CMB spectral distortions of μ< 6 × 10 −4 and |Yff| < 1 × 10 −4 . We also find a significant detection of a residual signal beyond that, which can be explained by the CMB plus the integrated radio emission from galaxies estimated from existing surveys. This residual signal may be due to an underestimated galactic foreground contribution, an unaccounted for contribution of a background of radio sources, or some combination of both. The residual signal is consistent with emission in the form of a power law with amplitude 18.4 ± 2.1 K at 0.31 GHz and a spectral index of −2.57 ± 0.05.

Antideuteron based dark matter search with GAPS: Current progress and future prospects

The General Antiparticle Spectrometer (GAPS) is a new approach to the indirect detection of dark matter. It relies on searching for primary antideuterons produced in the annihilation of dark matter in the galactic halo. Low energy antideuterons produced through Standard Model processes, such as collisions of cosmic-rays with interstellar baryons, are greatly suppressed compared to primary antideuterons. Thus a low energy antideuteron search provides a clean signature of dark matter. In GAPS antiparticles are slowed down and captured in target atoms. The resultant exotic atom deexcites with the emission of X-rays and annihilation pions, protons and other particles. A tracking geometry allows for the detection of the X-rays and particles, providing a unique signature to identify the mass of the antiparticle. A prototype detector was successfully tested at the KEK accelerator in 2005, and a prototype GAPS balloon flight is scheduled for 2011. This will be followed by a full scale experiment on a long duration balloon from Antarctica in 2014. We discuss the status and future plans for GAPS.

Measurement of drag and its cancellation

The design of drag cancellation missions of the future will take advantage of the technology experience of the past. The importance of data for modeling of the atmosphere led to at least six types of measurement: (a) balloon flights, (b) missile-launched falling spheres, (c) the ‘cannonball’ satellites of Ken Champion with accelerometers for low-altitude drag measurement (late 1960s and early 1970s), (d) the Agena flight of LOGACS (1967), a Bell MESA accelerometer mounted on a rotating platform to spectrally shift low-frequency errors in the accelerometer, (e) a series of French low-level accelerometers (e.g. CACTUS, 1975), and (f) correction of differential accelerations for drag errors in measuring gravity gradient on a pair of satellites (GRACE, 2002). The independent invention of the drag-free satellite concept by Pugh and Lange (1964) to cancel external disturbance added implementation opportunities. Its first flight application was for ephemeris prediction improvement with the DISCOS flight (1972)—still the only extended free test mass flight. Then successful flights for reduced disturbance environment for science measurement with gyros on GP-B (2004) and for improved accuracy in geodesy and ocean studies (GOCE, 2009) each using accelerometer measurements to control the drag-canceling thrust. LISA, DECIGO, BBO and other gravity wave-measuring satellite systems will push the cancellation of drag to new levels.

L’Aérostation au temps des Lumières (review)

Reviewed by: L’Aérostation au temps des Lumières Charles C. Gillispie (bio) L’Aérostation au temps des Lumières. By Marie Thébaud-Sorger. Rennes: Presses Universitaires de Rennes. 2009. Pp. 350. €19. This book is in keeping with a trend in postmodern historiography, most notably in France, wherein the focus is less on the events themselves than on their context and perception socially and culturally. Marie Thébaud-Sorger evokes the spectacular, not to say melodramatic, quality of balloon flights [End Page 394] during their first year, 1783–84. She treats the impression they made on the public as a case study of the permeation of what had been a largely literary culture by a new awareness of the role of institutional, cognitive, social, economic, and practical factors deriving from science and technology. Thus the account opens with the invention of the hot air balloon by Joseph de Montgolfier and its deployment in Paris by his brother Étienne as well as creation of the slightly later hydrogen balloon by J. A. C. Charles. The author treats the inventions themselves more or less incidentally to the interest they excited at many levels. Tout Paris watched the launches with fascination. Journalistic and literary coverage was dense. According to some accounts nothing less than a revolution in physics had transpired. What was the social and juridical situation of the inventors? Étienne de Montgolfier, manager of a provincial family paper business, was motivated by commercial and utilitarian considerations, unlike Charles, a physicist, whose purpose was scientific. Competition between the two approaches and methods was unstated but intense. The Academy of Sciences established a commission to investigate the scientific interest in and improvement of aerostatics. At issue was the nature of air itself. In addition to officialdom, the public soon began to play its part, a large part, and not only in Paris. Provincial periodicals and pamphlets abounded. The nature of hot air and hydrogen preoccupied the public on a par with that of the electrical fluid attracted to lightning rods and the universal fluid underlying Mesmer’s animal magnetism. What use would balloons have? Their very imperfections incited all manner of proposed improvements, for the most part having to do with methods of locomotion. The Academy of Lyons set a prize on that topic, never awarded, eliciting proposals from barely literate artisans to educated amateurs of science. Private persons made all sorts of experiments flying small balloons they made themselves, sometimes for pedagogical purposes, sometimes as simple diversions, sometimes with scientific pretensions. In short, public opinion became aware of conquest of the air as a technological frontier to be advanced in whatever ways possible. Financing the many demonstrations drew on subscriptions from members of the public admitted to launches, on local scientific or municipal authorities, and on philanthropic aristocrats. Full-scale experimental and demonstrative flights were mounted in major commercial cities such as Lyon, Dijon, Strasbourg, Toulouse, Bordeaux, and Nantes. There, and of course in Paris, the protagonists took care to stage the adventures as dramatically as possible, whence the lavish ornamentation of the envelopes and the fad of balloon iconography in all manner of prints and bric-a-brac. Personal interest attached to the exploits of the first two professional airmen, J. P. Blanchard and François Pilâtre de Rozier. In company with an American co-pilot, Blanchard piloted the first international flight from Dover to Flanders. Having been one of a pair aboard the first manned [End Page 395] flight, Pilâtre met death near Calais in the first air crash. Nothing if not thorough, Thébaud-Sorger has left no document unread, no page unturned, whether in Parisian or provincial, printed or unprinted, primary or secondary sources. Nor is any aspect of the topic untouched. Her approach precludes narrative treatment, however, and I find the presentation to be a little amorphous. Nevertheless, the sheer volume of detailed information conveys a sense of the dimensions of aerostatics in public sensibility in 1783–84. Charles C. Gillispie Charles C. Gillispie, Dayton-Stockton Professor Emeritus of History of Science at Princeton, is the author of The Montgolfier Brothers and the Invention of Aviation (1983) and Science and Polity in...

Validation of the Atmospheric Chemistry Experiment by noncoincident MkIV balloon profiles

[1] We have compared volume mixing ratio profiles of atmospheric trace gases measured by the Atmospheric Chemistry Experiment (ACE) version 2.2 and the MkIV solar occultation Fourier transform infrared spectrometers. These gases are H2O, O3, N2O, CO, CH4, HNO3, HF, HCl, OCS, ClONO2, HCN, CH3Cl, CF4, CCl2F2, CCl3F, COF2, CHF2Cl, and SF6. Due to the complete lack of close spatiotemporal coincidences between the ACE occultations and the MkIV balloon flights, we used potential temperatures and equivalent latitudes from analyzed meteorological fields to find comparable ACE and MkIV profiles. The results show excellent agreement for CH4, N2O, and other long-lived gases but slightly poorer agreement for shorter-lived species like CO, O3, and HCN. For example, in the upper troposphere (∼400–650 K), maximum differences between MkIV and ACE are 2.4% for CH4, 1.7% for N2O, −12.4% for CO, −15.9% for O3, and −5.6% for HCN. In the lower stratosphere (∼650–900 K), maximum MkIV-ACE differences are 7.6% for CH4, 14.1% for N2O, 7.3% for CO, −9.2% for O3, and 31.5% for HCN. Apart from a small vertical misregistration problem, the overall agreement between MkIV and ACE is very good.

The contribution by Domenico Pacini to the Cosmic Ray Physics

Between 1900 and 1913 several people were investigating about the unknown radiation, later identified as Cosmic Rays. Several experimentalist tried to identify the origin of this radiation and in particular Victor Franz Hess, Theodor Wulf and Domenico Pacini. Among them Domenico Pacini had a crucial role to address the answer to the origin of this radiation in the right way, and V.F.~Hess performed the complete set of measurements that definitively excluded an origin connected to the soil radioactive elements. However the most interesting and may be surprising point it that these pioneers defined 1 century ago the three experimental lines to study the Cosmic Rays: from space, on ground and underground and using only electroscopes. Domenico Pacini in particular may be considered the pioneer of the underground measurements on Cosmic Rays and Hess with his set of systematic measurements with balloon flights, originated the air-space studies on Cosmic Rays.

Sky Sailors: True Stories of the Balloon Era (review)

Reviewed by: Sky Sailors: True Stories of the Balloon Era Elizabeth Bush Bristow, David L. Sky Sailors: True Stories of the Balloon Era. Farrar, 2010. 134p. illus. with photographs ISBN 978-0-374-37014-5 $18.99 R* Gr. 4-8. Take aeronautics back, back, back before space shuttles, moon missions, airplanes, and dirigibles, and you arrive with Bristow at the late eighteenth to early twentieth century heyday of tethered and free-floating balloon flight, with its fearsome novelty and peculiar perils. Bristow traces the development of this lighter-than-air technology by examining some dozen or so practitioners, from scientists to showmen and -women, who used balloon ascent for everything from pure entertainment, to military surveillance, to exploration. Readers who may have had earlier picture-book encounters with the like of the Montgolfier brothers and their airborne animals (Priceman's Hot Air, BCCB 7/05) or Frenchman Jean-Pierre Blanchard and his American balloon debut (Wallner's The First Air Voyage in the United States, BCCB 5/96) will recognize old friends, but it's likely that few will know much, if anything, about other elements in Bristow's history, such as Blanchard's widow, Sophie, who set off fireworks from her highly flammable hydrogen-filled balloon; Coxwell and Glaisher's 1862 record-setting high-altitude ascent (sans oxygen tanks); or the 1858 accidental adventure of young siblings Martha and David Harvey in a runaway balloon. Mini physics lessons are incorporated throughout the text on a need-to-know basis, and even the youngest readers should grasp the essence of Bristow's concise explanations. A wealth of period illustrations, some in color, are included, and captions frequently point out errors in visual representation, due either to misinformation or to the urge to satisfy a thrill-hungry audience. With thorough source notes, an extensive bibliography, and a list of recommended websites (though no index), this is an inviting title for kids making their first ascents into longer works of nonfiction. Copyright © 2010 The Board of Trustees of the University of Illinois

Wasting away in Mars-Aritaville

Humans encountered physiological challenges as soon we began to leave the ground, first with balloons, then with planes, and more recently via rockets. Early high-altitude balloon flight exposed the sojourners to extreme cold and potentially lethal hypoxia (West, 1982). As planes became more powerful and manoeuvrable, pilots experienced severe G-forces that could limit brain perfusion and cause loss of consciousness. The problems of temperature, hypoxia and G-forces have all been solved with relatively straightforward countermeasures including supplemental oxygen, pressurized environments, improved clothing, and G-suits along with straining manoeuvres. The solutions to these problems have all also had significant translational implications with many finding a second home in clinical medicine. For example, the fundamental discoveries and engineering breakthroughs required to understand how humans respond to high G-forces, found second homes after the Second World War in the emerging fields of cardiac catheterization, cardiac surgery and critical care medicine. Many of the key advances were made by the legendary physician–scientist Earl Wood, who worked at my institution, the Mayo Clinic, during and after the Second World War (see the obituary of Earl Wood in the New York Times, 26 March 2009). Additionally, numerous advances in respiratory physiology with subsequent clinical applications owe their genesis to observations made at high altitude including those made during aviation. In contrast to the high G-forces experienced by the pilots of high-performance planes, weightlessness during space flight creates major problems for astronauts. The adaptations (or perhaps maladaptations) to space flight include rapid cardiovascular deconditioning and loss of blood volume, skeletal muscle wasting, and reductions in bone density. Endurance exercise training and acute bouts of high-intensity exercise can ameliorate much of the cardiovascular deconditioning and changes in blood volume associated with both medium-term (weeks) and long-term weightlessness (months). Additionally, head-down tilt bedrest appears to be a useful analogue for the cardiovascular deconditioning that occurs with prolonged space flight, making ground based studies highly informative (Engelke et al. 1996; Guinet et al. 2009). Along with cardiovascular deconditioning there are also losses of both skeletal muscle mass and bone density with space flight. In a recent issue of The Journal of Physiology, Fitts et al. (2010) reported that 180 days of space flight causes marked atrophy and force loss of skeletal muscle biopsy-derived fibres from space station crew members. In this context, the effects of space flight were especially evident in type 1 fibres of ‘anti-gravity’ muscles, like the soleus. Importantly, and in contrast to cardiovascular deconditioning, these effects were largely resistant to amelioration by concurrent exercise training in space. Along these lines there are a number of caveats and clinical observations that either inform or are informed by these findings. First, modern orthopaedic surgery has abandoned, when possible, extreme immobilization and this practice appears to have improved both the speed and efficacy of reconstructive surgery in a variety of settings. This trend includes rehabilitation from conditions like total joint replacement in older patients, and also knee reconstruction in elite athletes. Orthopaedic surgeons and physical therapists have learned the hard way that extreme skeletal muscle inactivity is devastating, slows recovery, and can lead even young healthy patients to a state where full recovery is limited. Second, crew members on the international space station could be generically described as middle-aged. If 6 months of minimal gravitational stress and physical activity can be associated with severe loss of muscle function, what does 20 or 30 years of physical inactivity do? There is already evidence that extreme physical inactivity for only 10 days can evoke a variety of metabolic changes that predispose the physically inactive to conditions like diabetes and obesity (Olsen et al. 2008). Third, frailty independent of other risk factors is a major contributor to premature death and disability in older humans (Schatz, 2002). This becomes even more apparent in individuals in their 70s and 80s. If effective countermeasures are developed for prolonged space flight, will they have implications for preventing, reducing, or reversing frailty in the elderly? Fourth, what about prolonged space flight? Exploration of Mars will require a mission of 3–4 years. Will muscle (and bone) loss be the scurvy of modern-day exploration, or will space flight make new contributions to medicine similar to those made by previous explorers in the areas of nutrition and hygiene? Along these lines, the discovery by Lind in the 1700s that citrus fruit (vitamin C) could treat scurvy is generally considered the first clinical trial. It is also an excellent example of how exploration, pathophysiology and medicine sometimes intersect for extremely applied reasons (Thomas, 1997). In summary, the paper by Fitts and colleagues shows that new and innovative countermeasures will be required as human exploration of space continues. If the history of these countermeasures from earlier aviation- and exploration-based experiences is any guide, the spinoffs for clinical medicine are likely to be large.

Development of tiled imaging CZT detectors for sensitive wide-field hard X-ray surveys to EXIST

Motivated by the proposed EXIST mission, a medium-class space observatory to survey black holes and the Early Universe proposed to the 2010 NAS/NRC Astronomy and Astrophysics Decadal Survey, we have developed the first large area 256 sq cm close-tiled (0.6 mm gaps) hard X-ray (20-600 keV) imaging detector employing pixelated (2.5 mm) CdZnTe (CZT) detectors, each 2 x 2 x 0.5 cubic cm. We summarize the design, development and operation of this detector array (8 x 8 CZTs) and its performance as the imager for a coded aperture telescope on a high altitude (40 km) balloon flight in October. 2009, as the ProtoEX1STl payload. We then outline our current development of a second-generation imager, ProtcEXIST2. with 0.6 mm pixels on a 32 x 32 array on each CZT, and how it will lead to the ultimate imaging system needed for EXIST. Other applications of this technology will also be mentioned.

Retrospect: November 11, 1935: Explorer II Stratospheric Balloon Flight

U.S. Weather Bureau Daily Weather Map for 8:00 a.m. EST (6:00 a.m. MST), November 11, 1935. An area of high pressure is centered over Minnesota, southeastern North Dakota, and eastern South Dakota....

Characteristics and performance of thin LaBr 3(Ce) crystal for hard X-ray astronomy

We have developed a new detector using thin lanthanum bromide crystal (32 × 3 mm) for use in X-ray astronomy. The instrument was launched in high altitude balloon flight on two different occasions, December 21, 2007, which reached a ceiling altitude of 4.3 mbs and April 25, 2008 reaching a ceiling altitude 2.8 mbs. The observed background counting rate at the ceiling altitude of 4 mbs was ∼4 × 10 −3 ct cm −2 s −1 keV −1 sr −1. This paper describes the details of the experiment, the detector characteristics, and the background behaviour at the ceiling altitude.

Study of seasonal variation of winds in upper stratosphere over Hyderabad

A predictability of the stratospheric zonal winds above 38 km during the turnaround is an essential parameter for planning of the high-altitude scientific balloon flights. This information is more relevant in the case of Hyderabad balloon facility which is closer to equator and has much more unstable wind reversal patterns which appears to have changed enormously during the last decade probably in correlation with the global warming. With a majority of our flights reaching the altitudes of 38–42 km and the requirement of long float durations, a prior knowledge of wind pattern during the summer and winter turnaround seasons is highly desirable. Furthermore, the flight operation corridor for balloon flights from Hyderabad is limited to 400 km and though in the west direction there are flat lands, in all other three directions, the landscape is dotted by water bodies, reserve forests and hilly terrain, and therefore need of such a data is essential. In order to establish the climatology of the stratospheric winds and study their inter-annual variability over Hyderabad for the turnaround periods, we have made a detailed analysis of the United Kingdom Meteorological office data between 2000 and 2007, to derive average wind parameters (magnitude, direction) at different ceiling altitudes above 38 km. These results can be used only as general trend of stratospheric wind and should not be the limitation of the UKMO Data.

An experience of participation of Russian specialists in international programs on atmospheric balloon investigations

The participation of Russian specialists in the international programs on balloon investigations of the ozone layer in the Arctic and in midlatitudes has been carried out since 1991. The specialists of Roshydromet took part in the organization and implementation of investigations in the Arctic and in midlatitudes within 11 projects as well as in tropical balloon campaigns. During this period, 42 balloon flights of different types were organized on the territory of Russia for the purpose of the measurement of atmospheric characteristics, of the validation of satellite device data, of the test of prototypes of future satellite meters. Besides, the investigations of ozone, water vapor, and aerosol content were carried out in various geographical zones (Hayes and Dickson islands, Salekhard, Yakutsk) using the small-volume balloons. The optical fluorescent hygrometer of the Central Aerological Observatory (CAO) is considered as one of the best instruments to measure the atmospheric humidity. Taking account of the reliability and accuracy of the measurements carried out, the values of the water vapor mixing ratio in the winter polar cyclone obtained with this hygrometer can be considered as the reference data.