Balloon Payload Research Articles

Stratospheric ozone isotope enrichments—Revisited

Ozone isotope data for 49O3 and 50O3 are presented, that were obtained from 28 stratospheric samples collected over 10 years onboard balloon payloads. Enrichments for 49O3 range from 7 to 9% in the middle stratosphere. This is in very good agreement with laboratory‐derived isotope predictions. For 50O3 most enrichments are between 7 and 11%, a few, however, are too high to be of atmospheric origin. Arguments are presented that stratospheric ozone isotope data are consistent with enrichments determined in laboratory studies when pressure and temperature dependence of the isotope effect is included. Results from recent remote sensing experiments support the values obtained during balloon‐borne sample collections. Very high enrichments occasionally measured in the past should be disregarded.

Lower stratospheric organic and inorganic bromine budget for the Arctic winter 1998/99

In the Arctic winter 1998/99, two balloon payloads were launched in a co‐ordinated study of stratospheric bromine. Vertical profiles (9–28 km) of all known major organic Br species (CH3Br, C2H5Br, CH2BrCl, CHBrCl2, CH2Br2, CHBr2Cl, CHBr3, H1301, H1211, H2402, and H1202) were measured, and total organic Br (henceforth called Bryorg) originating from these organic precursors was inferred as a function of altitude. This was compared with total inorganic reactive Br (henceforth called Bryin) derived from spectroscopic BrO observations, after accounting for modeled stratospheric Bry partitioning. Within the studied altitude range the two profiles differed by less than the estimated accumulated uncertainties. This good agreement suggests that the lower stratospheric budget and chemistry of Br is well understood for the specified conditions. For early 1999 our data suggest a Bryin mixing ratio of 1.5 ppt in air just above the local Arctic tropopause (∼9.5 km), whilst at 25 km in air of 5.6 yr mean age it was estimated to be 18.4(+1.8/−1.5) ppt from organic precursor measurements, and (21.5±3.0) ppt from BrO measurements and photochemical modelling, respectively. This suggests a Bryin influx of 3.1(−2.9/+3.5) ppt from the troposphere to the stratosphere.

Translating the mission: when the ground-truthers meet the instrument-makers-how students at all points in the "Pipeline" learn about remote sensing

In 1997 the Virginia Space Grant Consortium (VSGC) worked with Old Dominion University, Hampton University, Tidewater Community College and the College of William and Mary to develop a student team to manage the design, fabrication, and launch process for a scientific balloon payload. The expertise available to the VSGC suggested that an environmentally focused payload should address the instrumentation for gathering remotely sensed images and ground-truthing data. The payload was successfully launched on August 25, 1998. Throughout the project all team members worked with precollege students. Questions about the project were responded to through the "Ask A Scientist" page of the web site (http://ixeab2.larc.nasa.gov//sup -/killough/vsgc). The "Lessons Learned" included: 1) Student accountability for accuracy, safety, and project costs is critical, 2) Internet research projects require a high degree of organization, software compatibility, and self-efficacy: judgement that the student himself feels capable of participating in an on-line research project, and 3) The moment of "Aha!" is the primary motivator.

Laminae in the tropical middle stratosphere: Origin and age estimation

In situ measurements of N2O and O3 aboard the Observations from the Middle Stratosphere (OMS) balloon payload in the tropics are presented. In November 1997 at 7°S very distinct laminated structures in the N2O profile were observed in contrast to earlier studies based solely on O3 profiles. The laminae probably are an observation of Rossby wave‐breaking events that lead to transport of mid‐latitude air into the tropics. Using a photochemical model of the ozone response within those air parcels, their residence time in the tropics is estimated to be 4 to 6 weeks. In February 1997 at 7°S a similar vertical profile of N2O revealed no mid‐latitude laminae. We present dynamical arguments to support the existence of such laminae in November, but not in February.

Modification of a commercial condensation particle counter for boundary layer balloon-borne aerosol studies

It was shown that the newly designed balloon-borne CPC is able to measure vertical profiles of meteorological parameters simultaneously with the particle number concentration >12 nm. In order to investigate further new particle production in the upper part of the boundary layer a second counting channel was added to the balloon payload allowing concurrent measurement of particle concentrations >5 nm and >12 nm.

Simultaneous electric and magnetic field observations of Pc1–2, and Pc3 pulsations

This paper presents results from a combined analysis of ULF fluctuations in the geoelectric and geomagnetic fields. Data were obtained at South Pole station during the 1985–1986 South Pole Balloon Campaign. Magnetic field perturbations were measured by the two‐axis induction or “search coil” magnetometer at South Pole station. Vector electric field data were obtained by a standard double‐probe experiment on the balloon payloads. The objective of this study is to investigate the relationship between the electric and the magnetic components of geomagnetic micropulsations in the Pc1–3 frequency bands (0.01 to 0.5 Hz). The entire 468‐hour database of the balloon campaign has been searched for examples of strong discrete magnetic micropulsation emissions in these bands. The two best days were found to be January 7 and 8, 1986. Two emissions were seen on both days, a Pc3 emission between 30 and 40 mHz that extended for about 3 hours on either side of magnetic noon and a Pc1–2 emission that started around magnetic noon and lasted for several hours. The amplitude histories of the emissions were found to be roughly comparable when account was taken of the effect of varying precipitation on the ionospheric conductivity. The two components of the magnetic field did not show significant coherence. Consequently, little coherence was expected or found between the electric and magnetic components. An ionospheric transmission model has been used to interpret the observed B/E ratio in terms of the horizontal wave number of the source. The wave number that was inferred for the Pc3 emissions implies a phase speed roughly equal to the phase speed of simultaneous traveling convection vortex events.

A self-contained 3He refrigerator suitable for long duration balloon experiments

We describe the design, development and test of a self-contained 3He fridge, aimed to cool at ≲0.3 K a bolometric detection system with a hold time of two weeks. The system is robust and suitable for operation on a long-duration stratospheric balloon payload. A physical model of the fridge has been developed, which describes the measured hold time, limiting temperature and load curve of the fridge. The system has been flight tested successfully during two balloon flights of the BOOMERanG payload in summer 1997.

Advanced thin ionization calorimeter to measure ultrahigh energy cosmic rays

An Advanced Thin Ionization Calorimeter (ATIC) will be used to investigate the charge composition and energy spectra of primary cosmic rays over the energy range from about 10 10 to >10 14 eV in a series of long-duration balloon flights. The totally active BGO calorimeter, 22 radiation length thick, will measure the electromagnetic energy ensuing from nuclear interactions in a one interaction length thick carbon target. Trajectory information will be obtained from the location of the cascade axis in the BGO calorimeter and in the segmented scintillator layers of the upstream carbon target. The highly segmented charge module comprised of scintillator strips, a silicon matrix, and a Cherenkov array will minimize the effect of backscattered particles on primary charge measurements. While obtaining new high priority scientific results, the ATIC balloon payload can also serve as a proof of concept, or engineering model, for a BGO calorimeter-based instrument on the International Space Station. We examine the added advantage of locating such an experiment for long durations on a platform such as the Space Station.

Quantitative characterization of the x-ray imaging capability of rotating modulation collimators with laser light

We developed a method for making quantitative characterizations of bi-grid rotating modulation collimators (RMC's) that are used in a Fourier transform x-ray imager. With appropriate choices of the collimator spacings, this technique can be implemented with a beam-expanded He-Ne laser to simulate the plane wave produced by a point source at infinity even though the RMC's are diffraction limited at the He-Ne wavelength of 632.8 nm. The expanded beam passes through the grid pairs at a small angle with respect to their axis of rotation, and the modulated transmission through the grids as the RMC's rotate is detected with a photomultiplier tube. In addition to providing a quantitative characterization of the RMC's, the method also produces a measured point response function and provides an end-to-end check of the imaging system. We applied our method to the RMC's on the high-energy imaging device (HEIDI) balloon payload in its preflight configuration. We computed the harmonic ratios of the modulation time profile from the laser measurements and compared them with theoretical calculations, including the diffraction effects on irregular grids. Our results indicate the 25-in. (64-cm) x-ray imaging optics on HEIDI are capable of achieving images near the theoretical limit and are not seriously compromised by imperfections in the grids.

A system for grabbing integrated video frames remotely

A system for grabbing integrated video frames produced by a remote camera is described. As part of the pointed platform in a balloon-borne experiment, we use a video charge-coupled-device camera to obtain wide field star images. To obtain images with a sufficient signal-to-noise ratio, integration times of up to 1 s are required. In applications where the frame grabber and camera are physically close to each other, timing the frame grabber trigger is straightforward; however, there are several advantages to locating the frame grabber not on the balloon payload. As a result commands issued simultaneously to the frame grabber on the ground and the camera on the balloon can be delayed relative to each other, resulting in failure to acquire an image. We have developed a system where, at the end of an integration, a tone is injected into the video field preceding the transmission of the integrated frame; the tone is used on the ground by a decoder circuit to control the frame grabber acquisition of the integrated frame. The system has operated successfully in the flight of a stratospheric balloon-borne telescope.

CdZnTe detectors for gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS)

A CdZnTe detector array is being developed for the proposed gamma-ray Burst ArcSecond Imaging and Spectroscopy (BASIS) spaceflight mission to accurately locate gamma-ray bursts, determine their distance scale, and measure the physical characteristics of the emission region. Two-dimensional strip detectors with 100 μm pitch have been fabricated and wire bonded to readout electronics to demonstrate the ability to localize 60 and 122 keV gamma-rays to less than 100 μm. Radiation damage studies on a CdZnTe detector exposed to MeV neutrons showed a small amount of activation but no detector performance degradation for fluences up to 10 10 neutrons/cm 2. A 1 × 1 in. CdZnTe detector has also been flown on a balloon payload at 115 000 ft in order to measure the CdZnTe background rates.

A balloon-borne experiment to investigate the Martian magnetic field

The Space Research Institute of the Austrian Academy, of Sciences (Graz, Austria in cooperation with MPE (Berlin, Germany), GFZ Potsdam (Obs. Niemegk, Germany) IZMIRAN/IOFAN (Moscow, Russian) and IGPP/UCLA (Los Angeles, USA) is designing the magnetic field experiment MAGIBAL (MAGnetic field experiment aboard a martian BALloon) to investigate the magnetic field on the surface of Mars. The dual sensor fluxgate magnetometer is part of the MARS-98/MARS-TOGETHER balloon payload. During a ten days period the balloon will float over a distance of about 2000 km at altitudes between 0 and 4 km. Due to the limited power and telemetry allocation the magnetometer can transmit only one vector per ten seconds and spectral information in the frequency range from 2 – 25 Hz. The dynamic range is ± 2000 nT. The main scientific objectives of the experiment are: • • Determination of the magnetism of the Martian rocks • • Investigation of the leakage of the solar wind induced magnetosphere using the correlation between orbiter and balloon observations • • Measurement of the magnetic field profile between the orbiter and the surface of Mars during the descent phase of the balloon. Terrestrial test flights with a hot air balloon were performed in order to test the original MAGIBAL equipment under balloon flight conditions.

Balloon measurements above the south pole: Study of ionospheric transmission of ULF waves

We report here an experimental study of the Hughes and Southwood model of the transmission of electromagnetic signals from the ionosphere/magnetosphere to the lower atmosphere. The electric field data were obtained from one of eight high‐latitude balloon payloads launched above the south geographic pole during the South Pole Balloon Campaign in the 1985–1986 austral summer. The magnetic field data are from the South Pole magnetometer. The balloon payloads were instrumented with double‐probe electric field detectors and bremsstrahlung X ray detectors. One of the events from flight 7 (January 8, 1986, at 1500–1800 UT (1130–1430 MLT)) had an amplitude in the range of 10–20 mV/m and a period of several minutes. In the magnetosphere, the wave was probably an Alfvén mode. The wave event was superimposed on background fluctuations that can be attributed to turbulence. The results agree with the predictions of the model in that the best coherence is observed between parallel components of E versus B. The results disagree with the predictions of the model in two respects. First, we find a frequency structure not predicted by the model, and second, we find intervals where the electric and magnetic field polarizations are of opposite handedness. The first discrepancy was modeled by taking account of the measured electrostatic turbulence. The second problem remains a puzzle.

A balloon flight test of a coded-mask telescope with a multi-element germanium detector

The use of a small array of germanium detectors to obtain high spectral resolution X-ray and γ-ray images of astronomical objects has been demonstrated with a coded mask telescope flown as a piggy-back instrument on the NASA GRIS balloon payload. The design of the experimental telescope is discussed and images of the Crab nebula and of Cygnus X-1 obtained during the flight are presented. The quality of the images is shown to be very close to that expected from simulations.

A novel wide-field hard x-ray telescope

We discuss a hard x-ray telescope for the range 25–70 keV based on a one-dimensional lobster-eye telescope and x-ray supermirror coatings. This approach enables wide field-of-view imaging. A telescope suitable for a large balloon payload, with a 50×100 cm frontal area, could have an effective area of 50–100 cm2 and a 100×100 field of view, and thereby detect AGN that are 0.5 milliCrab in the soft x-rays in a 104 second exposure. 29% of the sky could be surveyed to this limit in a 2-week balloon flight, reaching 6 times fainter than the HEAO A-4 all-sky survey.

The 1991 WMO International ozonesonde intercomparison at Vanscoy, Canada

Abstract An intercomparison of ozonesondes was held at Vanscoy, Saskatchewan, from 13 to 24 May 1991. The intercomparison, which was sponsored by the WMO and hosted by the Atmospheric Environment Service (AES) of Canada, was attended by scientists from six countries: Canada, Finland Germany, India, Japan and the United States. Four different makes of ozonesondes were used: the ECC sonde, the Brewer‐Mast sonde, the Indian ozonesonde and the Japanese RSH‐KC79 ozonesonde. These represent most of the sonde types that are in routine operation in the Global Ozone Observing System. A balloon payload and telemetry system was developed to accommodate up to eight ozonesondes that could operate independently and transmit data simultaneously to a ground receiver. Ten flights were launched, each carrying 7 or 8 sondes, and a total of 65 successful profile measurements were made. The payloads were carried to altitudes between 35 and 40 km. The measured profiles are used to determine statistically meaningful evaluations of the different sonde types. The results compared with those from previous intercomparisons indicate that there has been a general improvement in performance for most of the types. In addition there appears to have been changes with time in the relative sensitivity to tropospheric ozone for different sonde types. This result should be considered when drawing conclusions regarding trends in tropospheric ozone.

Balloon observations of nightside Pc 5 quasi‐electrostatic waves above the South Pole

We report here a unique Pc 5 band quasi‐electrostatic wave event (∼300‐s period) observed near local geomagnetic midnight at an invariant latitude of 75°. The electric field signal was obtained from one of the eight high‐latitude balloon payloads launched above the south geographic pole during the South Pole Balloon Campaign in the 1985‐86 austral summer. The balloon payloads were instrumented with double‐probe electric field detectors and bremsstrahlung X ray detectors. The electric field data from one flight of particular interest have been compared with ground‐based magnetometer and micropulsation data in an attempt to understand the nature of the wave event. The Pc 5 waves were linearly polarized in the electric field, the electric field components had amplitudes of 20 to 30 mV/m, and the event persisted for an interval of more than 3 hours from 0000 to 0330 UT (2030 to 2400 MLT) on December 22, 1985. The magnetic activity was quiet during this time period. Detailed power spectra are presented in the paper. No evidence was found suggesting that the event was produced by an artifact. The event was not associated with atmospheric neutral waves, weather processes, or upward propagating gravity waves. The event was produced in the ionosphere by a process other than the convection of irregularities. We suggest that ULF magnetosonic waves originating at the magnetopause produced the signals that were observed.

Silicon calorimeter for cosmic antimatter search

The silicon sampling calorimeter presented is conceived as a fine grained imaging device to carry out studies of the anti-matter component in the primary cosmic radiation; it will be used in balloon payload program starting in 1993. The first sampling layer (48×48 cm 2) of this silicon calorimeter has been completed and successfully tested. We report the first results form studies performed at the CERN PS t 7 beam. The complete calorimeter contains 20 xy sampling layers (strip pitch 3.6 mm) interleaved with 19 showering material planes (tungsten 0.5 X 0). This allows to picture the transverse distributions of the shower in both coordinates at each sampling. The outstanding imaging capabilities reflects in high particle identification power. Preliminary results from beam tests performed with antiprotons at 3.5 GeV on a tower prototype of the calorimeter are reported.

The unrealized potential for heavy balloon payloads

Knowing that properties of new polyethylene films are superior to previous types, one would believe that heavier payloads can now be safely carried. Some experimentation has already been done to verify that assumption. Future expectations are discussed. We believe that with present-day materials, and with only limited changes in design philosophies, maximum payload weights can be increased by 50 to 75% from presently accepted maxima.

Detection of very soft X-ray spectra by balloon-borne detectors

A balloon payload launched from Cold Lake, Alta., Canada, on October 14, 1982, measured the spectrum of X rays (E = 20–160 keV) with a hard and a very soft component. The latter contributes significantly only to the 20–40 keV channel; thus a "flapping motion" at the lower energy end of the composite spectrum is observed. We have simulated, using the Monte-Carlo technique, the propagation of X rays through the atmosphere and determined the e-folding energy of the very soft component, which we estimate to be 5 keV, at a particular time (10:45 UT). The electron spectrum producing this soft X-ray source agrees well with in situ satellite and rocket-borne measurements of electron spectra during active auroras. Simulataneous auroral optical emissions (5577 Å (1 Å = 10−10 m)) by a ground-based all-sky charge-coupled device camera are also available for comparison. We also determine the count rate ratio between 20–40 and 60–80 keV channels as a parameter of the variability of the intensity of the very soft component. The time-changes of this ratio and that of the auroral optical emission intensity near the vicinity of the balloon are correlated. The lack of correlation at some other times is ascribed to differences in the behavior of the low- and high-energy ends of the elecron spectrum.