scholarly journals Orbital Design and Control for Jupiter-Observation Spacecraft

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 282
Author(s):  
Chunsheng Jiang ◽  
Yongjie Liu ◽  
Yu Jiang ◽  
Hengnian Li
Keyword(s):  
Local Time ◽  
Semimajor Axis ◽  
Disturbing Function ◽  
Atmospheric Drag ◽  
Third Body ◽  
Dynamical Models ◽  
Ground Track ◽  
The Third ◽  
Reasonable Range ◽  
And Control

This paper investigates the evolution of orbits around Jupiter and designs a sun-synchronous repeating ground track orbit. In the dynamical models, the leading terms of the Jupiter’s oblateness are J2 and J4 terms. A reasonable range of ground track repetition parameter Q is given and the best observation orbit elements are selected. Meanwhile, the disturbing function acting on the navigation spacecraft is the atmospheric drag and the third body. The law of altitude decay of the spacecraft’s semimajor orbit axis caused by the atmospheric drag is studied, and the inclination perturbation caused by the sun’s gravity is analyzed. This paper designs a semimajor axis compensation strategy to maintain the orbit’s repeatability and proposes an initial inclination prebiased strategy to limit the local time at the descending node in a permitted range. In particular, these two methods are combined in the context of sun-synchronous repeating ground track orbit for better observation of the surface of Jupiter.

scholarly journals Binary–binary scattering in the secular limit

2020 ◽  
Vol 494 (1) ◽  
pp. 850-867 ◽  
Author(s):  
Adrian S Hamers ◽  
Johan Samsing
Keyword(s):  
Globular Clusters ◽  
Semimajor Axis ◽  
Third Body ◽  
Triple Systems ◽  
Secular Changes ◽  
The Third ◽  
Numerical Integrations ◽  
Analytic Expressions ◽  
Order Change ◽  
Binary Separations

ABSTRACT Binary–binary interactions are important in a number of astrophysical contexts including dense stellar systems such as globular clusters. Although less frequent than binary–single encounters, binary–binary interactions lead to a much richer range of possibilities such as the formation of stable triple systems. Here, we focus on the regime of distant binary–binary encounters, i.e. two binaries approaching each other on an unbound orbit with a periapsis distance Q much larger than the internal binary separations. This ‘secular’ regime gives rise to changes in the orbital eccentricities and orientations, which we study using analytic considerations and numerical integrations. We show that ‘direct’ interactions between the three orbits only occur starting at a high expansion order of the Hamiltonian (hexadecupole order), and that the backreaction of the outer orbit on the inner two orbits at lower expansion orders is weak. Therefore, to good approximation, one can obtain the changes of each orbit by using previously known analytic results for binary–single interactions, and replacing the mass of the third body with the total mass of the companion binary. Nevertheless, we find some dependence of the ‘binarity’ of the companion binary, and derive explicit analytic expressions for the secular changes that are consistent with numerical integrations. In particular, the eccentricity and inclination changes of orbit 1 due to orbit 2 scale as ϵSA, 1(a2/Q)2[m3m4/(m3 + m4)2], where ϵSA, 1 is the approximate quadrupole-order change, and a2 and (m3, m4) are the companion binary orbital semimajor axis and component masses, respectively. Our results are implemented in several python scripts that are freely available.

scholarly journals Integrable Cases of Satellite Problem with the Third Body and the Oblate Planet

1974 ◽  
Vol 62 ◽  
pp. 117-124
Author(s):  
M. L. Lidov
Keyword(s):  
Elliptic Orbit ◽  
Disturbing Function ◽  
Third Body ◽  
The Third ◽  
Satellite Problem ◽  
Oblate Planet

The evolutions of satellite's orbit under the influence of the third disturbing body moving on an elliptic orbit and the oblate planet are studied by averaging the disturbing function, and integrable cases are classified in seven cases.

scholarly journals Expansion of the Disturbing Function by Factorization

1981 ◽  
Vol 63 ◽  
pp. 337-348
Author(s):  
R. Broucke ◽  
W. Presler
Keyword(s):  
Magnetic Tape ◽  
Disturbing Function ◽  
Third Body ◽  
The Third ◽  
Five Elements

AbstractWe present an expansion of the disturbing function for the third-body perturbations in the form , where ε is the ratio of semi-major axes (a/a’) and Xnm and Ynm depend only on the five elements e, i, ω, Ω, of the satellite while and depend on the corresponding elements of the perturbing body. Each one of the four functions X and Y is represented as a product of two factors as opposed to three factors in our previous publication of this subject (Broucke, 1981). We develop several relations for the construction of the X and Y-series. These series are relatively short and can be computed in advance and stored on magnetic tape, for instance.

THE EFFECT OF APPLYING DEMONSTRATION METHOD ON STUDENTS’ ACHIEVEMENT IN SPEAKING SKILL AT THE THIRD GRADE OF SMK PAB 3 MEDAN ESTATE

2015 ◽  
Vol 4 (2) ◽  
Author(s):  
Meryanti Napitupulu And Anni Holila Pulungan
Keyword(s):  
High School ◽  
Control Group ◽  
Vocational High School ◽  
Control Groups ◽  
Speaking Test ◽  
The Third ◽  
Speaking Skill ◽  
The Subject ◽  
And Control ◽  
Experimental Group

This study was conducted as an attempt to discover the effect of applying Demonstration Method on students’ achievement in speaking skill. It was an experimental research. The subject was students of Grade XII, Vocational High School (Sekolah Menengah Kejuruan: SMK), which consisted of 79 students. The research was divided into two groups: experimental and control groups. The instrument used to collect the data was speaking test. To obtain the reliability of the test, the writer applied Kuder Richardson 21 formula. The result of the reliability was 0.7, and it was found that the test was reliable. The data were analyzed by using t-test formula. The analysis showed that the scores of the students in the experimental group were significantly higher than the scores of the students in the control group at the level of significant m = 0.05 with the degree of freedom (df) 77, t-observed value 8.9 > t-table value 1.99. The findings indicate that using Demonstration Method significantly affected the students’ achievement in speaking skill. So, English teachers are suggested to use Demonstration Method in order to improve students’ achievement in speaking skill.

MODEL OF SOCIAL POTENTIAL OF CHILDHOOD IN THE RUSSIAN REGIONS: THE RESULTS OF EXPERIMENTS

2019 ◽  
pp. 152-162
Author(s):  
A.G. Filipova ◽  
A.V. Vysotskaya
Keyword(s):  
Third Wave ◽  
Russian Regions ◽  
The Third ◽  
Control Factors ◽  
Social Potential ◽  
System Input ◽  
Optimal Values ◽  
Fixed Ideal ◽  
And Control ◽  
Selection Of

The article presents the results of mathematical experiments with the system «Social potential of childhood in the Russian regions». In the structure of system divided into three subsystems – the «Reproduction of children in the region», «Children’s health» and «Education of children», for each defined its target factor (output parameter). The groups of infrastructure factors (education, health, culture and sport, transport), socio-economic, territorial-settlement, demographic and en-vironmental factors are designated as the factors that control the system (input parameters). The aim of the study is to build a model îf «Social potential of childhood in the Russian regions», as well as to conduct experiments to find the optimal ratio of the values of target and control factors. Three waves of experiments were conducted. The first wave is related to the analysis of the dynam-ics of indicators for 6 years. The second – with the selection of optimal values of control factors at fixed ideal values of target factors. The third wave allowed us to calculate the values of the target factors based on the selected optimal values of the control factors of the previous wave.

scholarly journals Mating Disruption of Pseudococcus calceolariae (Maskell) (Hemiptera, Pseudococcidae) in Fruit Crops

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 343
Author(s):  
Carolina Ballesteros ◽  
Alda Romero ◽  
María Colomba Castro ◽  
Sofía Miranda ◽  
Jan Bergmann ◽  
...  
Keyword(s):  
Visual Inspection ◽  
Mating Disruption ◽  
Economic Importance ◽  
Fruit Crops ◽  
Potential Control ◽  
The Third ◽  
Pseudococcus Calceolariae ◽  
And Control ◽  
Potential Use ◽  
Control Tool

Pseudococcus calceolariae, the citrophilous mealybug, is a species of economic importance. Mating disruption (MD) is a potential control tool. During 2017–2020, trials were conducted to evaluate the potential of P. calceolariae MD in an apple and a tangerine orchard. Two pheromone doses, 6.32 g/ha (2017–2018) and 9.45 g/ha (2019–2020), were tested. The intermediate season (2018–2019) was evaluated without pheromone renewal to study the persistence of the pheromone effect. Male captures in pheromone traps, mealybug population/plant, percentage of infested fruit at harvest and mating disruption index (MDI) were recorded regularly. In both orchards, in the first season, male captures were significantly lower in MD plots compared to control plots, with an MDI > 94% in the first month after pheromone deployment. During the second season, significantly lower male captures in MD plots were still observed, with an average MDI of 80%. At the third season, male captures were again significant lower in MD than control plots shortly after pheromone applications. In both orchards, population by visual inspection and infested fruits were very low, without differences between MD and control plots. These results show the potential use of mating disruption for the control of P. calceolariae.

scholarly journals Extended analytical formulae for the perturbed Keplerian motion under low-thrust acceleration and orbital perturbations

2021 ◽  
Vol 133 (3) ◽  
Author(s):  
Marilena Di Carlo ◽  
Simão da Graça Marto ◽  
Massimiliano Vasile
Keyword(s):  
Gravitational Perturbation ◽  
Low Thrust ◽  
Orbital Elements ◽  
Third Body ◽  
The Third ◽  
Orbital Perturbations ◽  
Analytical Formulae ◽  
Numerical Orbit ◽  
Body Potential

AbstractThis paper presents a collection of analytical formulae that can be used in the long-term propagation of the motion of a spacecraft subject to low-thrust acceleration and orbital perturbations. The paper considers accelerations due to: a low-thrust profile following an inverse square law, gravity perturbations due to the central body gravity field and the third-body gravitational perturbation. The analytical formulae are expressed in terms of non-singular equinoctial elements. The formulae for the third-body gravitational perturbation have been obtained starting from equations for the third-body potential already available in the literature. However, the final analytical formulae for the variation of the equinoctial orbital elements are a novel derivation. The results are validated, for different orbital regimes, using high-precision numerical orbit propagators.

scholarly journals Futures of sustainability: Perspectives on social imaginaries and social transformation. A comment on Frank Adloff and Sighard Neckel’s research program

2021 ◽  
pp. 053901842199956
Author(s):  
Gerard Delanty
Keyword(s):  
Conceptual Framework ◽  
Research Program ◽  
Social Transformation ◽  
Research Agenda ◽  
Social Imaginaries ◽  
The Third ◽  
The Future ◽  
And Control

This essay is a comment on the research program launched by Frank Adloff and Sighard Neckel. My comment is specifically focused on their research agenda as outlined in their trend-setting article, ‘Futures of sustainability as modernization, transformation, and control: A conceptual framework’. The comment is also addressed more generally to the research program of the Humanities Centre for Advanced Studies ‘Futures of Sustainability’. I raise three issues: the first relates to the very idea of the future; the second concerns the notion of social imaginaries and the third question is focused on the idea of social transformation.

Sign in / Sign up

Export Citation Format

Share Document