Systems for long duration flights

This paper describes the systems for long duration flights developed in Japan for scientific observations. Much efforts have been expended to evolve systems for long duration flights in Japan, by controlling the balloon trajectories with a knowledge of wind pattern at high altitudes over Japan. These systems called “Cycling Balloon”, “Boomerang Balloon” and “New Boomerang Balloon” have been successfully used for the observations by keeping the balloons close to the balloon station.“Relay Balloon” is another system to extend the telemetry range by using an additional balloon as a relay station to link the telemetry from the main balloon.Some detailes of the exhaust valve, ascent meter and automatic level control devices used for the balloon control are also described in the paper.     

Measurements of atmospheric ozone from aircraft and from balloons

The first ozone data from the Northern Hemisphere meridional flight “SIMOC” are presented. The flight was made in May of 1981 from Germany up to 82 °N and then down to the Equator and back with the Falcon 20E German research aircraft. These data include those obtained using a differential solar absorption spectrometer developed and built at the Max-Planck-Institut für Aeronomie in Lindau. Ozone profiles obtained from an intensive series of balloon flights launched in northern Sweden over a two week period are also presented and discussed in terms of the variability in ozone concentration that they demonstrate in the middle atmosphere.     

Towards the automated operations of large distributed satellite systems. Part 2: Classifications and tools

Recent developments have seen a trend towards larger constellations of spacecraft, with some proposals featuring constellations of more than 10.000 satellites. While similar concepts for large constellations already existed in the past, traditional satellite deployments hardly ever feature groups of more than 100 satellites. This trend towards considerably larger satellite numbers originates from non-traditional design and operations of spacecraft by non-traditional space companies. The evolution in the space sector, precipitated by new players, is often referred to as “Space 4.0” or “New Space”. It necessitates a rethinking of the way satellites and satellite constellations are planned, designed, and operated. New operational paradigms are needed to enable automatic, optimal task definition, and scheduling in a holistic approach.This is the second of two companion papers that investigate the operations of distributed satellite systems. This second article investigates the classification of distributed satellite systems and evaluates commercial tools for automated spacecraft operations, whereas the first article performed a survey of conventional and “new space”operations of spacecraft constellations.Classification metrics for constellations are derived and evaluated with respect to their informative value concerning the operation, the automation, and the scalability of the constellation. The proposed classification system is applied to the Dove and RapidEye constellation and allows for a comparison between the presented automation approaches. Commercial tools for automated spacecraft operations are evaluated for several mission task elements, such as orbit control, orbit maintenance, and collision avoidance. Subsequently, the trends, benefits, and standardization needs for operational automation are identified.     

Horizontal winds in the mesosphere at high latitudes

A total of 146 meteorological rocket flights applying the ‘falling sphere’ technique are used to obtain horizontal winds in the mesosphere at polar latitudes, namely at the Andøya Rocket Range (69°N, 125 flights), at Spitsbergen (78°N, 10 flights), and at Rothera (68°S, 11 January flights only). Nearly all flights took place around noon or midnight, i.e., in the same phase of the semidiurnal tide. Meridional winds at 69°N show a clear diurnal tidal variation which is not observed in the zonal winds. The zonal wind climatology shows a transition from summer to winter conditions with the zero wind line propagating upward from 40 km (end of August) to 80 km (end of September). Zonal winds are smaller at Spitsbergen compared to Andøya which is in line with a common angular velocity at both stations. Meridional winds at noon are of similar magnitude at all three stations and are directed towards the north and south pole, respectively. Horizontal and meridional winds generally agree with empirical models, except for the zonal winds at Antarctica which are similar to the NH, whereas there is a significant SH/NH difference in CIRA-1986.     

Relationships of a growing magnetic flux region to flares

Some sites for solar flares are known to develop where new magnetic flux emerges and becomes abutted against opposite polarity pre-existing magnetic flux (review by Galzauskas/1/). We have identified and analyzed the evolution of such flare sites at the boundaries of a major new and growing magnetic flux region within a complex of active regions, Hale No. 16918. This analysis was done as a part of a continuing study of the circumstances associated with flares in Hale Region 16918, which was designated as an FBS target during the interval 18 – 23 June 1980. We studied the initiation and development of both major and minor flares in Hα images in relation to the identified potential flare sites at the boundaries of the growing flux region and to the general development of the new flux. This study lead to our recognition of a spectrum of possible relationships of growing flux regions to flares as follows: (1) intimate interaction with adjacent old flux — flare sites centered at new/old flux boundary, (2) forced or “intimidated” interaction in which new flux pushes old field having lower flux density towards a neighboring old polarity inversion line where a flare then takes place, (3) “influential” interaction — magnetic lines of force over an old polarity inversion line, typically containing a filament, reconnect to the new emerging flux; a flare occurs with erupting filament when the magnetic field overlying the filament becomes too weak to prevent its eruption, (4) inconsequential interaction — new flux region is too small or has wrong orientation for creating flare conditions, (5) incidental — flare occurs without any significant relationship to new flux regions.     

Balloon observations of temporal and spatial fluctuations in stratospheric conductivity

The first campaign of the Polar Patrol Balloon (PPB) experiment (1st-PPB) was carried out at Syowa Station in Antarctica during 1990–1991 and 1992–1993. Based on the results of the 1st-PPB experiment, the next campaign (2nd-PPB) was carried out in the austral summer of 2002–2003. This paper will present stratospheric conductivity results from the 2nd-PPB experiment. In that experiment, three balloons were launched for the purpose of upper atmosphere physics observation (three balloons). Payloads of these three flights were identical with each other, and were launched as close together in time as allowed by weather conditions to constitute a cluster of balloons during their flights. Such a “Balloon Cluster” is suitable to observe temporal evolution and spatial distribution of phenomena in the ionospheric regions and boundaries that the balloons traversed during their circumpolar trajectory. More than 20 days of simultaneous fair weather 3-axis electric field and stratospheric conductivity data were obtained at geomagnetic latitudes ranging from sub-auroral to the polar cap. Balloon separation varied from ∼60 to >1000 km. This paper will present stratospheric conductivity observations with emphasis on the temporal and spatial variations that were observed.     

Janus: An aircraft prototype of a low earth orbit split beam stereoscopic observing system

The principle of determination of wind fields by a tomographic method is described. The airborne stereoscopic radiometer JANUS has been built to assess the feasibility of such measurements. Results of preliminary flights over isolated cumulus compare favourably with direct measurements. New flights with improved auxiliary parameter determinations are ongoing.     

CRISTA-NF measurements of water vapor during the SCOUT-O3 Tropical Aircraft Campaign

The new remote sensing experiment CRISTA-NF (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere – New Frontiers) successfully participated in the SCOUT-O3 Tropical Aircraft Campaign in November and December 2005. CRISTA-NF operated aboard the high-altitude research aircraft M-55 Geophysica. Mid-infrared spectra (4–15 μm) were measured in the limb sounding geometry with high spatial resolution (250 m vertical sampling, 5–15 km along track sampling). Measurements were carried out during transfer flights between Oberpfaffenhofen, Germany, and Darwin, Australia, as well as during several local flights near Darwin. Water vapor volume mixing ratios in the upper troposphere and lower stratosphere were derived from the CRISTA-NF radiance measurements by utilizing a rapid radiative transfer forward model and the optimal estimation retrieval approach. CRISTA-NF water vapor measurements below the hygropause have a total retrieval error of 15–40% (i.e. root mean square of accuracy and precision). The systematic terms are dominating in the retrieval error budget. The contributions of a priori information to the retrieval results are less than 5–10%. The vertical resolution of the observations is about 250–500 m when permitted by instrument sampling. In this paper we present first results for three transfer flights of the campaign. Being generally in good agreement with corresponding ECMWF operational analyzes, the CRISTA-NF measurements show significantly higher variability and local structures in the upper tropospheric water vapor distributions.     

Scientific ballooning in Japan

Activities in scientific ballooning in Japan during 1998–1999 are reported. The total number of scientific balloons flown in Japan in 1998 and 1999 was sixteen, eight flights in each year. The scientific objectives were observations of high energy cosmic electrons, air samplings at various altitudes, monitoring of atmospheric ozone density, Galactic infrared observations, and test flights of new type balloons. Balloon expeditions were conducted in Antarctica by the National Institute of Polar Research, in Russia, in Canada and in India in collaboration with foreign countries' institutes to investigate cosmic rays, Galactic infrared radiation, and Earth's atmosphere. There were three flights in Antarctica, four flights in Russia, three flights in Canada and two flights in India. Four test balloons were flown for balloon technology, which included pumpkin-type super-pressure balloon and a balloon made with ultra-thin polyethylene film of 3.4 μm thickness.     

The theoretical advantages and practical considerations of gas replenishment techniques in long-duration scientific ballooning

Long-duration scientific balloon flights using conventional ballasting methods to compensate for daily loss of lift suffer a severe payload weight penalty. Typically, the weight of the expendable ballast approaches or exceeds the weight of the balloon and payload. This paper examines the concept of correcting for degraded lift by “gas replenishment” techniques, that is, by replacing lost helium inflatant from an on-board dewar. Appropriate equations are developed and curves are presented which demonstrate the clear theoretical superiority of the replenishment method. Design problems associated with the dewars and heat exchangers required to implement the gas replenishment concept are also discussed in detail. A series of curves is presented in which net load, dewar weight and quantity of helium required are plotted for specific balloons and float altitudes as a function of daily loss rate. The lack of relevant heat exchange data in the literature is cited as an obstacle to immediate prototype development.     

Development overview of the revised NASA Ultra Long Duration Balloon

The desire for longer duration stratospheric flights at constant float altitudes for heavy payloads has been the focus of the development of the National Aeronautics and Space Administration’s (NASA) Ultra Long Duration Balloon (ULDB) effort. Recent efforts have focused on ground testing and analysis to understand the previously observed issue of balloon deployment. A revised approach to the pumpkin balloon design has been tested through ground testing of model balloons and through two test flights. The design approach does not require foreshortening, and will significantly reduce the balloon handling during manufacture reducing the chances of inducing damage to the envelope. Successful ground testing of model balloons lead to the fabrication and test flight of a ∼176,000 m³ (∼6.2 MCF – Million Cubic Foot) balloon. Pre-flight analytical predictions predicted that the proposed flight balloon design to be stable and should fully deploy. This paper provides an overview of this first test flight of the revised Ultra Long Duration Balloon design which was a short domestic test flight from Ft. Sumner, NM, USA. This balloon fully deployed, but developed a leak under pressurization. After an extensive investigation to the cause of the leak, a second test flight balloon was fabricated. This ∼176,000 m³ (∼6.2 MCF) balloon was flown from Kiruna, Sweden in June of 2006. Flight results for both test flights, including flight performance are presented.     

The development of plastic,zero pressure balloon design since 1945

There have been four major thrusts in plastic, zero pressure balloon design in the U.S. since the late 1940's. First, the pioneer balloonists made designs according to geometric shapes. When these balloons began to fail, a study at the University of Minnesota produced the first mathematical model for determining the proper design for “natural shaped” balloons. With the advent of high speed digital computing came the “Sigma” tables of the 1960's. When computers became more widespread and inexpensive, direct or “full-sized” designs began to be used. Now, with the problems involved in flying heavy payloads (greater than 400 lbs) and super pressure balloons, a new tool has become available to the balloon designer. An inexpensive stress analysis code is available but is as yet unproven.     

High altitude flights in equatorial regions

A thorough analysis of balloon flights made from Hyderabad, India (Latitude 17°28′N, Longitude 78°35′E), and other equatorial sites has been made. It has been shown that limited success is expected for flights made from equatorial latitudes with balloons made out of natural colour polyethylene film, since the best known balloon film in the world today viz. Winzen Stratofilm is tested for low temperature brittleness only at ?80°C., whereas the tropopause temperatures over equatorial latitudes vary between ?80°C and ?90°C. The success becomes even more critical when flights are made with heavy payloads and larger balloons particularly at night when in the absence of solar radiation the balloon film becomes more susceptible to low temperature brittle failure. It is recommended that in case of capped balloons longer caps should be used to fully cover the inflated protion of the balloon at the higher level equatorial tropopause. It is also advised that the conditions such as wind shears in the tropopause should be critically studied before launching and a day with the tropopause temperature nearer to ?80°C should be chosen. Special care also should be taken while handling the balloon on ground and during launching phase. Properties of Winzen Stratofilm have been critically studied and fresh mandates have been recommended on the basis of limiting values of film stresses which caused balloon failures in the equatorial tropopause. It is also emphasized that the data on such flights is still meagre especially for flights with heavy payloads and larger balloons. It has been also shown that it is safest to use balloons made out of grey coloured film which retains its flexibility with the absorption of solar radiation, the success obtained with such balloons so far being 100%. The drawback, however, is that these balloons cannot be used for night flights. Stratospheric wind regimes over Hyderabad are also discussed with a view to determine the period over which long duration flights can be made. The data available, however, is meagre and it is recommended that more frequent special wind ascents be made to collect adequate statistical data from which reliable conclusions could be drawn through critical analysis.     

Medium energy gamma ray astronomy with transpacific balloon flights

Transpacific balloon flights with the University of California, Riverside (UCR) double scatter telescope are discussed. With flight durations from 5 days up to perhaps 15 days the long observation times necessary for medium energy (1–30 MeV) gamma ray astronomy can be obtained. These flights would be made under the auspices of the Joint U.S.-Japan Balloon Flight Program at NASA. We propose that flights can provide at least 30 hours of observation time per flight for many discrete source candidates and 120 hours for detecting low intensity cosmic gamma ray bursts.     

Detection of solar neutrons on a long duration balloon flight

The observation of large solar flares on high altitude balloons requires long duration balloon flights because large flares are infrequent and cannot be predicted with enough reliability and lead time to allow a conventional balloon to be launched and reach altitude before the flare occurs. With the many weeks at float altitude expected for a long duration flight, the probability of “catching” a large flare during solar maximum becomes reasonably high and the study of phenomena which heretofore have required a satellite become accessible to a balloon platform. One example of this type of experiment is the observation of neutrons produced by the interaction of flare accelerated nucleons with the solar atmosphere. Because the neutrons are produced immediately by the flare accelerated particles and are unaffected by their transmission through the upper solar atmosphere and the intervening magnetic fields, their observation at 1 A.U. will provide direct information on the flare acceleration process. Specifically, a measurement of the neutron energy and time spectra will yield the energy spectrum of the charged nucleons in the interval 50 to 500 MeV/amu, the charged particle anisotropy, the height of the acceleration region for limb flares, and information on the two-stage acceleration process. Because the γ-ray spectrum is also sensitive to these factors, a combined neutron and γ-ray measurement will provide a much more stringent test of flare models than either done separately. CWRU and the University of Melbourne have designed the EOSCOR (Extended Observation of Solar and Cosmic Radiation) detector to have the necessary sensitivity to detect neutrons from a flare 0.1 the size of the 4 Aug. 1972 event and to be compatible with the constraints of the long duration balloon system. The detector has been test flown on short duration balloon flights and calibrated at E_n = 38, 58, and 118 MeV. It is planned to launch it on a long duration balloon flight from Australia in December 1982 when simultaneous γ-ray observations will be possible with the SMM and/or HINTORI satellites.     

Millimeter-wave spectroscopy and mapping of quasar hosts,and the status of ULIRGS as Quasar 2s

It is becoming possible to detect high redshift quasars in various molecular lines, and to show by mapping lensed objects that the strong dust and molecular emission arises in warm dense ∼ 100 pc-scale “tori.” The properties of ULIRGS, at least those with AGN-like narrow line regions, are very similar, as expected in the hidden quasar hypothesis. Several of the latter are in fact confirmed as “Quasar 2s” by spectropolarimetry. I argue against claims that the source of the majority of the luminosity has been determined in any ULIRG or Scuba sources.     

Analysis of gravity-wave induced instabilities and turbulence viscosity parameters from optical emissions

The effects of gravity waves on OH and 5577 0I emissions have been used to investigate (1) the possible production of “secondary” waves or “ripples” by a “primary” wave; (2) the possible application of such observed optical emissions for computing atmospheric parameters such as turbulence viscosity in the mesospheric regions.     

Electromagnetic containerless undercooling facility and experiments for the shuttle

An electromagnetic furnace is being prepared for flights aboard the space shuttle. This apparatus is capable of melting metals and alloys up to 1400°C melting point by induction heating with subsequent solidification of the freely levitated melt without contact with any container. The solidification can be carried out with greatly reduced fields resulting in minimal heating and stirring of the free melt. Sequential specimens can be processed during flight. Several experiments are planned for a series of flights, beginning in 1985 with an undercooling experiment on NiSn alloys. These will be interspersed with detailed studies of fluid flow caused by low and high field levels in order to quantify the corresponding effect upon the solidification process.     

Girl — the German infrared laboratory for spacelab

GIRL is a liquid helium cooled 50 cm telescope equipped with four focal plane instruments dedicated to astronomical and aeronomical observations. These instruments, a detector array, a photopolarimeter, an Ebert-Fastie-spectrometer and a Michelson-interferometer make up an “infrared observatory” having high sensitivity and high spectral and spatial resolution. Si:Ga-, Si:Sb-, Si:As-, Si:P-, Ge:Be-, Ge:Cu- and Ge:Ga-detectors with NEP-values as low as $\text{3 10}{}^{\mathrm{?17}}\text{W Hz}{}^{\mathrm{<mtext>?1</mtext><mtext>2</mtext>}}$ have been tested and will be used to cover the wavelength range 3…120 μm. A full size “thermal model” of the GIRL cryostat containing 300 1 of superfluid helium at 1.6 K has been tested at the industrial prime contractor MBB; results of these tests will be presented in a following paper by F. Dahl et al. Several new techniques for cold telescopes are used in GIRL, for instance a glass ceramics primary mirror, a low power chopping secondary and an active helium phase separator. The scientific objectives include studies of star formation regions and active galaxies as well as measurements of spurious gases in the earth atmosphere. GIRL will be pointed by the Instrument Pointing System (IPS) and is scheduled to fly on Spacelab in 1986/87.     

Advanced ensemble modeling method for space object state prediction accounting for uncertainty in atmospheric density

For objects in the low Earth orbit region, uncertainty in atmospheric density estimation is an important source of orbit prediction error, which is critical for space traffic management activities such as the satellite conjunction analysis. This paper investigates the evolution of orbit error distribution in the presence of atmospheric density uncertainties, which are modeled using probabilistic machine learning techniques. The recently proposed “HASDM-ML,” “CHAMP-ML,” and “MSIS-UQ” machine learning models for density estimation (Licata and Mehta, 2022b; Licata et al., 2022b) are used in this work. The investigation is convoluted because of the spatial and temporal correlation of the atmospheric density values. We develop several Monte Carlo methods, each capturing a different spatiotemporal density correlation, to study the effects of density uncertainty on orbit uncertainty propagation. However, Monte Carlo analysis is computationally expensive, so a faster method based on the Kalman filtering technique for orbit uncertainty propagation is also explored. It is difficult to translate the uncertainty in atmospheric density to the uncertainty in orbital states under a standard extended Kalman filter or unscented Kalman filter framework. This work uses the so-called “consider covariance sigma point (CCSP)” filter that can account for the density uncertainties during orbit propagation. As a test-bed for validation purposes, a comparison between CCSP and Monte Carlo methods of orbit uncertainty propagation is carried out. Finally, using the HASDM-ML, CHAMP-ML, and MSIS-UQ density models, we propose an ensemble approach for orbit uncertainty quantification for four different space weather conditions.