Empirical model of the high-latitude boundary of the Earth’s outer radiation belt at altitudes of up to 1000 km

An empirical model of the high-latitude boundary of the outer Earth’s radiation belt (ERB) has been presented, which is based on the measurement data of electron fluxes on the polar low-orbit CORONAS-Photon, Meteor-M1, and Meteor-M2 satellites. The boundary was determined by a sharp decrease to the background level of the flux of trapped electrons with energies of 100 or 200 keV in the polar part of the profile of the outer radiation belt. A numerical algorithm has been implemented to determine the time moment, when the fastest flux changes are recorded. The primary search was carried out, first, on 30 s averaged data, then repeated on data with a higher resolution. A functional dependence was obtained in order to approximate the obtained set of intersections of the boundary by elliptical curve. The empirical model constructed using the CORONAS-Photon measurement data in the epoch of anomalously low geomagnetic activity reflects the longitude structure of the high-latitude boundary of the outer radiation belt associated with the internal Earth’s magnetic field (MF), as well as its dependence on the universal time. Based on the data of intersections of the high-latitude boundary of the outer ERB (OERB) in the epoch of 2014–2016, the latitudinal shift of the boundary to the equator dependent on geomagnetic activity has been determined, as well as the nightside shift of the boundary due to the diurnal rotation of the Earth.     

Feasibility study of astronaut standardized career dose limits in LEO and the outlook for BLEO

Cosmic Study Group SG 3.19/1.10 was established in February 2013 under the aegis of the International Academy of Astronautics to consider and compare the dose limits adopted by various space agencies for astronauts in Low Earth Orbit. A preliminary definition of the limits that might later be adopted by crews exploring Beyond Low Earth Orbit was, in addition, to be made. The present paper presents preliminary results of the study reported at a Symposium held in Turin by the Academy in July 2013. First, an account is provided of exposure limits assigned by various partner space agencies to those of their astronauts that work aboard the International Space Station. Then, gaps in the scientific and technical information required to safely implement human missions beyond the shielding provided by the geomagnetic field (to the Moon, Mars and beyond) are identified. Among many recommendations for actions to mitigate the health risks potentially posed to personnel Beyond Low Earth Orbit is the development of a preliminary concept for a Human Space Awareness System to: provide for crewed missions the means of prompt onboard detection of the ambient arrival of hazardous particles; develop a strategy for the implementation of onboard responses to hazardous radiation levels; support modeling/model validation that would enable reliable predictions to be made of the arrival of hazardous radiation at a distant spacecraft; provide for the timely transmission of particle alerts to a distant crewed vehicle at an emergency frequency using suitably located support spacecraft. Implementation of the various recommendations of the study can be realized based on a two pronged strategy whereby Space Agencies/Space Companies/Private Entrepreneurial Organizations etc. address the mastering of required key technologies (e.g. fast transportation; customized spacecraft design) while the International Academy of Astronautics, in a role of handling global international co-operation, organizes complementary studies aimed at harnessing the strengths and facilities of emerging nations in investigating/solving related problems (e.g. advanced space radiation modeling/model validation; predicting the arrivals of Solar Energetic Particles and shocks at a distant spacecraft). Ongoing progress in pursuing these complementary parallel programs could be jointly reviewed bi-annually by the Space Agencies and the International Academy of Astronautics so as to maintain momentum and direction in globally progressing towards feasible human exploration of interplanetary space.     

Optimization of measurements of the Earth’s radiation belt particle fluxes

The Earth’s radiation belts discovered at the end of the 1950s have great scientific and practical interest. Their main characteristics in magnetically quiet periods are well known. However, the dynamics of the Earth’s radiation belts during magnetic storms and substorms, particularly the dynamics of relativistic electrons of the outer belt, when Earth’s radiation belt particle fluxes undergo significant time variations, is studied insufficiently. At present, principally new experiments have been performed and planned with the intention to better study the dynamics of the Earth’s radiation belts and to operationally control the space-energy distributions of the Earth’s radiation belt particle fluxes. In this paper, for spacecraft designed to measure the fluxes of electrons and protons of the Earth’s radiation belts at altitudes of 0.5–10000 km, the optimal versions for detector orientation and orbital parameters have been considered and selected.     

The Martian and extraterrestrial UV radiation environment. Part II: further considerations on materials and design criteria for artificial ecosystems.

Ultraviolet radiation is an important natural physical influence on organism function and ecosystem interactions. The UV radiation fluxes in extraterrestrial environments are substantially different from those experienced on Earth. On Mars, the moon and in Earth orbit they are more biologically detrimental than on Earth. Based on previously presented fluxes and biologically weighted irradiances, this paper considers in more detail measures to mitigate UV radiation damage and methods to modify extraterrestrial UV radiation environments in artificial ecosystems that use natural sunlight. The transmission characteristics of a Martian material that will mimic the terrestrial UV radiation environment are presented. Transmissivity characteristics of other Martian and lunar materials are described. Manufacturing processes for the production of plastics and glass on the lunar and Martian surface are presented with special emphasis on photobiological requirements. Novel UV absorbing configurations are suggested.     

Evolution of the out-of-plane amplitude for quasi-periodic trajectories in the Earth–Moon system

The out-of-plane amplitude along quasi-periodic trajectories in the Earth–Moon system is highly sensitive to perturbations in position and/or velocity as underscored recently by the ARTEMIS spacecraft. Controlling the evolution of the out-of-plane amplitude is non-trivial, but can be critical to satisfying mission requirements. The sensitivity of the out-of-plane amplitude evolution to perturbations due to lunar eccentricity, solar gravity, and solar radiation pressure is explored and a strategy for designing low-cost deterministic maneuvers to control the amplitude history is also examined. The method is sufficiently general and is applied to the L₁ quasi-periodic orbit that serves as a baseline for the ARTEMIS P2 trajectory.     

Applications of multi-body dynamical environments: The ARTEMIS transfer trajectory design

The application of forces in multi-body dynamical environments to permit the transfer of spacecraft from Earth orbit to Sun–Earth weak stability regions and then return to the Earth–Moon libration (L₁ and L₂) orbits has been successfully accomplished for the first time. This demonstrated that transfer is a positive step in the realization of a design process that can be used to transfer spacecraft with minimal Delta-V expenditures. Initialized using gravity assists to overcome fuel constraints; the ARTEMIS trajectory design has successfully placed two spacecrafts into Earth–Moon libration orbits by means of these applications.     

Penetration of solar cosmic rays into the Earth’s magnetosphere on January 28, 2012

Results of the comparative analysis of the dynamics of SCR fluxes with energies of 1–100 MeV in the interplanetary environment according to the data of the ACE and Wind spacecraft and within the Earth’s magnetosphere according to the data of the GOES-15 and Electro-L satellites in the region of geostationary orbits, and POES-19 and Meteor-M1 in the region of polar caps during two increases in SCR of January 19–31, 2012, are presented. It is shown that the decrease in the efficiency of SCR penetration into the Earth’s magnetosphere in the region of the orbits under study on January 28, 2012, is related to the passage of the Earth’s magnetosphere through the interplanetary environment structure with a quasi-radial interplanetary magnetic field and a small pressure of the solar wind.     

一种利用地球敏感器的星光导航方法

针对直接敏感地平的红外地平仪-星光导航系统精度低的问题,提出通过建立扁率误差补偿函数,研究扁率引起的姿态角测量误差;建立地心矢量的姿态角误差模型,通过修正地球扁率误差来补偿姿态角,对卫星施加姿态偏转指令调整地心矢量偏移。同时基于SODERN地球红外辐射模型,考虑红外辐射强度随纬度和季节的变化建立真实红外辐射曲线,通过滤波算法获得精确的地球切线边缘的量测信息,提高红外地平仪测量精度。仿真结果表明,该方法有效提高了基于红外地平仪的星光导航定位方法的可靠性和精度,导航位置误差能达到500m左右,较原有系统提高3倍以上。     

Experiment on the <Emphasis Type="Italic">Vernov</Emphasis> satellite: Transient energetic processes in the Earth’s atmosphere and magnetosphere. Part I: Description of the experiment

The program of physical studies on the Vernov satellite launched on July 8, 2014 into a polar (640 × 830 km) solar-synchronous orbit with an inclination of 98.4° is presented. We described the complex of scientific equipment on this satellite in detail, including multidirectional gamma-ray detectors, electron spectrometers, red and ultra-violet detectors, and wave probes. The experiment on the Vernov satellite is mainly aimed at a comprehensive study of the processes of generation of transient phenomena in the optical and gamma-ray ranges in the Earth’s atmosphere (such as high-altitude breakdown on runaway relativistic electrons), the study of the action on the atmosphere of electrons precipitated from the radiation belts, and low- and high-frequency electromagnetic waves of both space and atmospheric origin.     

NEOs as stepping stones to Mars and main-belt asteroids

Human interplanetary missions are constrained by the problem of astronaut exposure to galactic cosmic radiation. This paper surveys the existing on-line near-Earth object (NEO) data base in an effort to identify NEOs that cross both Earth's ad Mars’ orbits and could be used as cosmic ray shields by interplanetary voyagers. The search concentrated on low-inclination Mars-crossing NEOs that approach Earth, Mars, and main-belt asteroids in the 2020–2100 time frame. Both outbound and return transfers were searched for. Several candidates for Earth–Mars, Mars–Earth, and Earth–Vesta transfers have been found from the very incomplete August 2008 data base. Other aspects of this interplanetary transfer option are considered.     

红外地平仪姿态测量误差模型

分析得出地球扁率和红外辐射是扫描式红外地平仪测量误差的主要原因。针对地球扁率，基于方位角的确定，分别给出了滚动角和俯仰角的测量误差模型。在地球红外辐射方面，给出了确定地平仪扫人、扫出点位置的方法，进而给出地球红外辐射误差的计算方法。最后，通过算例，给出了有关仿真结果，对方法的有效性进行了验证。     

A deterministic computational model for the two dimensional electron and photon transport

A deterministic (non-statistical) two dimensional (2D) computational model describing the transport of electron and photon typical of space radiation environment in various shield media is described. The 2D formalism is casted into a code which is an extension of a previously developed one dimensional (1D) deterministic electron and photon transport code. The goal of both 1D and 2D codes is to satisfy engineering design applications (i.e. rapid analysis) while maintaining an accurate physics based representation of electron and photon transport in space environment. Both 1D and 2D transport codes have utilized established theoretical representations to describe the relevant collisional and radiative interactions and transport processes. In the 2D version, the shield material specifications are made more general as having the pertinent cross sections. In the 2D model, the specification of the computational field is in terms of a distance of traverse z along an axial direction as well as a variable distribution of deflection (i.e. polar) angles θ where −π/2<θ<π/2, and corresponding symmetry is assumed for the range of azimuth angles (0<φ<2π). In the transport formalism, a combined mean-free-path and average trajectory approach is used. For candidate shielding materials, using the trapped electron radiation environments at low Earth orbit (LEO), geosynchronous orbit (GEO) and Jupiter moon Europa, verification of the 2D formalism vs. 1D and an existing Monte Carlo code are presented.     

Program goals for the NASA/NOAA Earth Observation Program derived from a stakeholder value network analysis

The 2007 US National Research Council Decadal Survey for Earth Science and Applications from Space was the first consensus perspective produced by the US Earth Science community of the relative priorities among a sequence of 17 satellite missions over the course of the next decade. However, the Decadal Survey only captured the perspective of the science community, leading to questions about the inclusion of broader priorities from constituent communities and stakeholders. We present a stakeholder value network analysis for the NASA/NOAA Earth Observation Program. The analysis includes a rigorous articulation of the needs and objectives of 13 major stakeholders and a complete stakeholder value network with 190 individual “value flows” that capture the interactions between all the stakeholders. It produces a novel stakeholder map, graphically indicating the outputs most likely to create a lasting Earth Science program. The most important value loops and program outputs are used to derive a set of high-level program goals that suggest what NASA and NOAA should do, as well as how they should conduct business. The analysis concludes that international partnerships represent a strong potential partner for certain science missions with greater potential value delivery than currently-prioritized efforts with defense stakeholders and concludes that weather and land-use missions, in addition to climate missions, should be given highest priority; water, human health, and solid Earth missions should be given lower priority based on each science category's potential for delivering value to the entire stakeholder network.     

地球辐射带槽区粒子环境动态变化对中轨卫星辐射效应的影响

中轨卫星运行于地球辐射带槽区,而槽区粒子辐射环境可能存在显著涨落,增加卫星抗辐射设计输入的不确定性.文章利用典型地球辐射带模型,对中轨卫星累积性辐射效应的主要来源进行深入分析,再结合槽区粒子辐射环境动态变化特征,初步量化分析其对中轨卫星遭遇辐射效应的影响.结果表明:槽区粒子辐射环境的动态变化对星表材料及太阳电池辐射损伤...     

条带式太阳帆航天器的热致结构动力学响应

本文研究条带式太阳帆在近地轨道运行进出地球阴影时的热致结构动力学响应，建立了在太阳热辐射和光压共同作用下的太阳帆结构动力学方程，采用分布传递函数法，给出了条带式太阳帆热致结构稳态振动幅频响应的计算方法。算例结果表明：热辐射冲击是引起近地轨道太阳帆结构动力学响应的主要原因，光压引起的结构响应可忽略不计；增加桅杆壁厚不能有效抑制太阳帆的热致结构动态响应；增大阻尼，减小结构的热膨胀系数能够明显减小太阳帆热致结构响应的振幅；热致结构动态响应是设计大尺寸近地轨道太阳帆必须解决的问题。本文提出的方法可为太阳帆结构设计、姿态和轨道控制提供有力的分析工具。     

Assessment on the feasibility of future shepherding of asteroid resources

Most plausible futures for space exploration and exploitation require a large mass in Earth orbit. Delivering this mass requires overcoming the Earth's natural gravity well, which imposes a distinct obstacle to any future space venture. An alternative solution is to search for more accessible resources elsewhere. In particular, this paper examines the possibility of future utilisation of near Earth asteroid resources. The accessibility of asteroid material can be estimated by analysing the volume of Keplerian orbital element space from which Earth can be reached under a certain energy threshold and then by mapping this analysis onto an existing statistical near Earth objects (NEO) model. Earth is reached through orbital transfers defined by a series of impulsive manoeuvres and computed using the patched-conic approximation. The NEO model allows an estimation of the probability of finding an object that could be transferred with a given Δv budget. For the first time, a resource map provides a realistic assessment of the mass of material resources in near Earth space as a function of energy investment. The results show that there is a considerable mass of resources that can be accessed and exploited at relatively low levels of energy. More importantly, asteroid resources can be accessed with an entire spectrum of levels of energy, unlike other more massive bodies such as the Earth or Moon, which require a minimum energy threshold implicit in their gravity well. With this resource map, the total change of velocity required to capture an asteroid, or transfer its resources to Earth, can be estimated as a function of object size. Thus, realistic examples of asteroid resource utilisation can be provided.     

通信卫星地平信号的自适应观测处理器

本文分析了国际上通用的以地平边缘的红外辐射信号作为卫星天线系统基准信号所存在的问题,应用控制理论和数字计算原理,提出了地平信号“取中”的自适应处理方法。依据这一方法,在我国通信试验卫星控制系统设计中,设计了地平信号自适应观测处理器,给出稳定的“地中”信号,作为自旋卫星天线消旋系统的基准信号。通过误差分析以及地面模拟试验和几次飞行试验充分证明,本文所提出的红外地平信号“取中”设计方案的正确性。此方案优于国际通用的红外地平“边缘”方案。     

太阳电池对平流层飞艇热特性的影响分析

研究太阳电池对平流层飞艇驻空阶段热特性的影响。建立了太阳电池热模型、平流层飞艇热分析模型,包括热平衡方程、太阳直射辐射、天空散射辐射、地面反射辐射、大气长波辐射、地球长波辐射、蒙皮长波辐射、对流换热等;采用多节点模型,对平流层飞艇在驻空期间太阳电池、蒙皮与艇内氦气温度变化过程进行了数值模拟,得到了温度昼夜变化规律;分析了太阳电池（含隔热结构）的等效面积热阻、转换效率、铺装面积对平流层飞艇热特性的影响,得到了其温度昼夜变化规律。本文为平流层飞艇热性能分析和热控系统设计提供依据。     

Short increases of the fluxes of electrons with energies > 0.08 MeV at low-latitude (<Emphasis Type="Italic">L</Emphasis> < 2) regions of near-Earth space

We present the characteristics of short (duration less than 1 min) increases of the counting rate of electrons with energies >0.08 MeV observed in low-latitude (L < 2.0) regions of near-Earth space in the course of the GRIF experiment on the Spektr module of the Mir orbital station. The measurements were carried out using a set of instruments including X-ray and gamma-ray spectrometers, as well as detectors of electrons, protons, and nuclei with large and small geometrical factors, which allowed one to detect the fluxes of charged particles both in the region of the Earth’s radiation belts and in regions close to the geomagnetic equator. As a result of more than 1.5 years of observation, it is demonstrated that short increases in the intensity of electrons of subrelativistic energies are detected not only in the regions of the near-Earth space known as “precipitation zones” (1.7 < L < 2.5), but in high-latitude regions (up to the geomagnetic equator, L < 1.1) as well. Two types of increases of the electron counting rate are found: either fairly regular increases repeating on successive orbits or increases local in time. The latter type of increases can be caused by a short enhancement of electron flux on a given drift shell. The results of our measurements have shown that the duration of the detected increases in intensity can be rather short, as little as 20–30 s. Therefore, in the case of large amplitudes, such increases of the counting rate of electrons can imitate astrophysical events of the type of cosmic gamma-ray bursts in the detectors of hard X-ray and gamma radiation.     

Hectometer radio bursts and energetic electrons during solar flares according to observations onboard the Interball-1 satellite

Radio bursts in the frequency range 100–1500 kHz and fluxes of energetic electrons with energies of 20–450 keV recorded onboard the Interball-1 satellite during prominent chromospheric flares on the Sun are studied. The time of propagation of the electrons to the Earth is estimated using the method of comparison of the moments of the beginning of radio emission generation during the explosive phase of the flare and the arrival of the accelerated electrons to the Earth.