Telemetry,telecommand and safety sub-systems for scientific ballooning from Hyderabad

Highly sophisticated balloon-borne scientific payloads have stringent requirement on the telemetry and command system. The development and fabrication of the on-board TT&C package for telemetry, tracking, command, safety and ranging for these experiments is done in-house at the National Balloon Facility (NBF) at Hyderabad. In the last few years, we have made major improvements both in the ground station and the on-board sub-systems, thereby improving the data quality, data handling speed and the general flight control along with aviation safety. The new system has telemetry data rate up to 1 Mbps. A reduction in weight, power and cost of the reengineered on-board integrated package has also lead to the ease of operation during field tests prior to launch and at remote recovery sites. In this paper, we describe the details of the new control package, its flight performance and our plans for portable S-band telemetry and telecommand system to cater to the balloon flights from Antarctic station and long duration balloon flights.     

通信卫星的成本分析

本文提出了估算静止通信卫星各分系统生产成本、整星成本和空间活动总成本的数学模型。为了按分系统估算成本,首先给出了估算各分系统质量的模型。只需已知卫星的初始在轨质量,即可算出卫星平台各分系统、有效载荷的质量和成本、整星成本和空间活动总成本。本文也为通信卫星方案论证工作中的分系统质量分配,提供了一种简单易行的工程设计方法。     

Power supplies for long duration balloon flights

Long duration balloon flights require more electrical power than can be carried in primary batteries. This paper provides design information for selecting rechargeable batteries and charging systems. Solar panels for recharging batteries are discussed, with particular emphasis on cells mounting suitable for balloon flights and panel orientation for maximum power collection. Since efficient utilization of power is so important, modern DC to DC power conversion techniques are presented.On short flights of 1 day or less, system designers have not been greatly concerned with battery weight. But, with the advent of long duration balloon flights using superpressure balloons, anchor balloon systems, and RACOON balloon techniques, power supplies and their weight become of prime importance. The criteria for evaluating power systems for long duration balloon flights is performance per unit weight. Instrumented balloon systems have flown 44 days. For these very long duration flights, batteries recharged from solar cells are the only solution. For intermediate flight duration, say less than 10 days, the system designer should seriously consider using primary cells.     

A new balloon base in Japan

Since 1971, numerous balloons have been launched from the Japanese balloon base, the Sanriku Balloon Center (SBC). Through these years, balloon technologies have been developed continuously and many scientific achievements have resulted. Recently, however, because of the limited area of the launching pad of the SBC, we have been faced with the difficulty of safely launching large balloons. To solve this issue, we decided to move the balloon base from the SBC to the Taiki Aerospace Research Field (TARF) in northern Japan. The TARF had an existing huge hanger and a paved launch pad capable of being utilised for balloon operations. To evolve the TARF into a new balloon base, new balloon facilities have been constructed at the TARF and equipment was transferred from the SBC to the TARF during July 2007 and March 2008. The SBC was closed in September 2007, and the new base became operational in May 2008. The new base at the TARF is designed to launch larger balloons with greater safety and to perform balloon operations more effectively than ever before. In the summer of 2008, we carried out the first series of the balloon campaign at the TARF, and succeeded in two engineering flights of stratospheric balloons. By the success of these flights, we have verified that the whole system of the new balloon base is well established.     

A stress index model for balloon design

The modern day scientific research balloon has historically maintained an approximate 85% success rate as launched by the USA National Scientific Balloon Facility (NSBF). Failures were across all operational phases and modes. Balloons fabricated after 1980 have met with less favorable results with catastrophic failures on ascent becoming the principle failure mode. In 1983, the USA National Aeronautics and Space Administration (NASA) conducted an intensive investigation to identify the possible causes for these failures. Although the most probable cause was identified as the balloon material, additional contributing factors were identified. One of these factors, balloon stress, was calculated using a stress equation defining only the total required thickness for launch. No model existed to predict the stress distribution in an ascending balloon. Early in 1984, NASA began the development of a stress index model to establish the relative stress magnitudes at any altitude. Studies were conducted applying this model to several hundred balloon flights. The study indicated a strong correlation between stress levels, failure rates, and the point of maximum stress coinciding with observed failure locations. In January 1985, NASA instituted a stress index design and flight specification that all NASA balloons must meet. The details and results of this work are presented.     

Program of balloon launchings in Indonesia in the 1980s

The stratospheric balloon program in Indonesia was initiated in the year 1974, by sending a team to CNES, France, to undergo a job training. The first balloon launching conducted in the year 1975 and since then other launchings have been carried out regularly. The launchings were done on the island of Bali and East Java, because these areas are ideal of that purpose as the upperwind over these areas almost constantly blows easterly.The program of balloon launchings in the 1980's will be improved by the construction of a permanent launching station situated in Mojokerto, East Java, and the addition of Rawin sonde RD 650 CS equipment, Balte Telecommand with 10 addresses and recovery equipment. The volume of balloons will be larger i.e. up to 13.000 m³, enabling to carry heavier payload for longer flight time duration. Also a tethered balloon will be operated for experimentation of TV relay station and communication, especially remote areas.     

Balloon-borne,high-altitude gravimetry

Gravity measurements from a high-altitude balloon can verify global and upward-continued gravity models. A gravimeter suspended beneath a balloon is in a dynamic, and largely unpredictable, environment sensing accelerations due to gravity and balloon motions. Independent measurements of balloon motions using inertial navigation data combined with ground tracking data will allow for separation of balloon-induced accelerations from gravitational accelerations. Analysis of these data must estimate: 1) vertical gravimeter accelerations due to motion and gravity, 2) horizontal velocity to estimate the Eötvös effect, and 3) gravimeter position for comparison with gravity models. The first engineering test flight occurred on 11 October 1983, during the seasonal wind reversal and was very successful. Flight duration was approximately seven hours, with two hours of data collected at each of 30 km and 26 km altitudes. The results include gravity estimates, design criteria for future flights and feasibility analysis for vertical gravity profiles during ascent and descent.     

A review of geostationary satellite alternatives for retrieving data from long duration balloon flights

Low speed data from high altitude scientific balloon flights can be retrieved by geostationary satellites through existing data collection platform systems. Higher speed data of the order of 1 kbit/s create a more difficult problem, particularly if a response is to be made to the balloon payload in near real time. Different geostationary satellite methods to achieve these more demanding requirements are reviewed, and the more interesting cases identified for possible future experiments.     

Living plant systems: How robust are they in the absence of gravity?

The following hierarchical levels can be recognised in plant systems: cells, organs, organisms and gamodemes (interbreeding members of a community). Each level in this ‘living hierarchy’ is both defined and supported by a similar set of sub-systems. Within this framework of plant organization, two complementary questions are relevant for interpreting plant-oriented space experiments: 1) What role, if any, does gravity play in enabling the development of each organizational level? and 2) Does abnormal development in an altered gravity environment indicate sub-system inefficiency? Although a few representatives of the various organizational levels in plant systems have already been the subject of microgravity experiments in space laboratories—from cells in culture to gamodemes, the latter being found in some Closed Environment Life Support Systems—it would be of interest to investigate additional systems with respect to their response to microgravity. Recognition of the sub-systems at each level might be relevant not only for a more complete understanding of plant development but also for the successful cultivation and propagation of plants during long-term space flights and the establishment of plants in extra-terrestrial environments.     

Present status and new trends in scientific ballooning in India

The efforts in scientific ballooning in India have always been focussed towards continuous upgrading of capabilities in all aspects of balloon flights - balloon material, balloon fabrication, launch techniques, heavy payload launch, telemetry, telecommand and other ground facilities - to meet the growing demands of the scientific community. A brief account of recent progress in several of these aspects and future plans for further improvements in scientific ballooning capability is presented.     

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.     

双层乳胶气球的高空平漂机理及垂直轨迹模拟

双层乳胶气球克服了单层乳胶气球的缺点,可以在高空平漂以实现持续气象观测,但是其高空平漂受多因素影响比较复杂,特别是气球充气量主要依赖工程经验,施放成功率不高,亟需提供理论指导。通过试验数据证明了浮重平衡是双层乳胶气球实现高空平漂的必要条件,推导得出内、外球氢气充气量和昼夜温度变化对其运动的影响;建立了双层乳胶气球的几何模型和动力学模型,结合实地施放试验,对其升空和平漂过程轨迹进行模拟,由此探究了内、外球充气量对平漂高度的影响。研究结果表明:内球充气量是决定平漂高度的主要因素,并受昼夜温度变化影响,当内、外球规格分别为750g、500g,负载约1kg时,内球拉力每增大或减小0.04kg,最终平漂高度将对应升高或降低约5km,而外球充气量对其平漂高度无影响。      

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.     

Properties of tandem balloons connected by extendable suspension wires

The tandem balloon system has been known as a candidate system for long duration flight balloons. In this paper, the properties of the system are analytically studied in a new way by introducing an extendable suspension wire in the Sky Anchor configuration, which consists of a zero-pressure main balloon suspending a payload and a super-pressure balloon suspended below the payload. It was found that extension of the suspension wire between the payload and the super-pressure balloon can extend the capability of the tandem system; the altitude of the zero-pressure balloon can be changed without any consumables except some energy, and the day–night oscillation of the balloon altitude can be suppressed. This property is useful as the vehicle for long duration flights. It is also pointed out that the method to control the altitude of a balloon using an additional suspended super-pressure balloon can also be applied for super-pressure balloons.     

Relay balloon

A relay balloon system for long-duration or large-area observations is described. The system consists of a balloon for scientific observations and a relay balloon for a data-relay terminal between a ground station and the balloon for observation. The system was successfully applied to the observation of electric-power fields (50 and 60 Hz) over the Pacific ocean. The maiximum distance between two balloons was about 1100 km and that between the Sanriku Balloon Center and the main balloon for the observation was about 1300 km.     

Technology development for a long duration,mid-cloud level Venus balloon

This paper describes the results of ongoing technology development activities for a Venus spherical superpressure balloon capable of flying for long durations (30 days) in the middle cloud layer at an altitude of 55.5 km. Data is presented from a successful aerial deployment and inflation flight experiment on a 5.5 m diameter prototype balloon conducted at a 2.5 km altitude above the Earth. Although the balloon in that test was not released for free flight, all other steps in the deployment and inflation process were successfully executed. Experimental and computational results are also presented from an investigation of the stress concentration phenomenon at the junction of the metal end fitting and fabric end cap of the prototype Venus balloon. Good agreement was found between the simulation and experimental results and a stress concentration factor of 1.55 determined for this end cap design compared to the expectations of thin membrane theory. Finally, results are presented for a new, second-generation Venus balloon material utilizing Aclar™ film instead of Teflon. Optical property and sulfuric acid tolerance data are presented for this material based on laboratory testing of samples.     

Evolution of scientific ballooning and its impact on astrophysics research

As we celebrate the centennial year of the discovery of cosmic rays on a manned balloon, it seems appropriate to reflect on the evolution of ballooning and its scientific impact. Balloons have been used for scientific research since they were invented in France more than 200 years ago. Ballooning was revolutionized in 1950 with the introduction of the so-called natural shape balloon with integral load tapes. This basic design has been used with more or less continuously improved materials for scientific balloon flights for more than a half century, including long-duration balloon (LDB) flights around Antarctica for the past two decades. The U.S. National Aeronautics and Space Administration (NASA) is currently developing the next generation super-pressure balloon that would enable extended duration missions above 99.5% of the Earth’s atmosphere at any latitude. The Astro2010 Decadal Survey report supports super-pressure balloon development and the giant step forward it offers with ultra-long-duration balloon (ULDB) flights at constant altitudes for about 100 days.     

Scientific ballooning in Japan – An over view of recent activities

Current status of scientific ballooning in Japan is reviewed. First, I describe successful application of balloon technologies to construct a vessel of transparent plastic film, to contain about 1000 tons of liquid scintillator in Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND). KamLAND is a project to study neutrino oscillation phenomena, by detecting anti-neutrinos produced in distant nuclear reactors. Next, I describe high altitude balloons developed by the ISAS balloon group. They developed balloons made from ultra-thin polyethylene film, producing a balloon of volume 60,000 m³ which successfully reached an altitude of 53 km in 2002. This is a world record, the greatest altitude that a balloon has ever achieved. ISAS is applying further effort to develop balloons with even thinner films, to achieve a higher altitude than 53 km. Other recent activities by the ISAS balloon group are briefly described.I also review scientific ballooning projects now operating in Japan, particularly focusing on the Balloon-Borne Experiment with a Superconducting Spectrometer (BESS) program. This is a US–Japan collaborative program that has carried out very precise measurements of antiprotons, protons and other components in primary cosmic rays, as well as measuring the fluxes of atmospheric muons and other components. The results of these observations give us important information to improve our understanding of the production mechanism of antiprotons observed in the primary cosmic rays. The data are also important for analysis of atmospheric neutrino events observed by Super-Kamiokande and other ground-based neutrino detectors. Future prospects of BESS and other balloon-borne cosmic-ray research programs are also presented.     

Performance simulation of high altitude scientific balloons

The design and operation of a high altitude scientific balloon requires adequate knowledge of the thermal characteristics of the balloon to make it safe and reliable. The thermal models and dynamic models of altitude scientific balloons are established in this paper. Based on the models, a simulation program is developed. The thermal performances of a super pressure balloon are simulated. The influence of film radiation property and clouds on balloon thermal behaviors is discussed in detail. The results are helpful for the design and operate of safe and reliable high altitude scientific balloons.