scholarly journals King-Hele orbit theory for periodic orbit and attitude variations

2020 ◽  
Vol 501 (1) ◽  
pp. 1168-1187
Author(s):  
Vishal Ray ◽  
Daniel J Scheeres
Keyword(s):  
Drag Coefficient ◽  
Dynamic Parameter ◽  
Mission Design ◽  
Fourier Series Expansion ◽  
Satellite Orbits ◽  
Physical Interaction ◽  
Satellite Mission ◽  
Simplifying Assumptions ◽  
Time Variations ◽  
Specific Factors

ABSTRACT The analytical theory of satellite orbits in an atmosphere developed by King-Hele remains widely in use for satellite mission design because of its accurate approximation to numerical integration under simplifying assumptions. Over the course of six decades, modifications to the theory have addressed many of its weaknesses. However, in all subsequent modifications of the original theory, the assumption of a constant drag-coefficient has been retained. The drag-coefficient is a dynamic parameter that governs the physical interaction between the atmosphere and the satellite and depends on ambient as well as satellite specific factors. In this work, Fourier series expansion models of the drag-coefficient are incorporated in the original King-Hele theory to capture time-variations of the drag-coefficient in averaging integrals. The modified theory is validated through simulations that demonstrate the attained improvements in approximating numerical results over the original King-Hele formulation.

Visualizing models and observations of the thermosphere-ionosphere in support of the ESA EE10 candidate mission Daedalus

2020 ◽  
Author(s):  
Eelco Doornbos ◽  
Theodoros Sarris ◽  
Stylianos Tourgaidis ◽  
Panagiotis Pirnaris ◽  
Stephan Buchert ◽  
...  
Keyword(s):  
Local Density ◽  
Lower Thermosphere ◽  
Satellite Orbits ◽  
Heating Rates ◽  
Satellite Mission ◽  
Temporal And Spatial Variability ◽  
Phase 0 ◽  
Definition Of ◽  
2D And 3D

<p>Daedalus is a new satellite mission concept for studying the lower thermosphere-ionosphere (LTI). The mission is currently undergoing Phase 0 studies, funded by ESA as one of three missions that are candidates for becoming its Earth Explorer 10 mission (EE10).</p><p>Using an elliptical orbit with a very low perigee (140 km and lower), the mission will make comprehensive in-situ measurements, including local density, composition, temperature and velocities of both the neutral and charged particles. An option of having two Daedalus satellites is being studied to allow better separation of temporal and spatial variability, and to better measure the strong vertical gradients and wave activity that occur in the LTI. The complete suite of instruments on Daedalus will allow the computation of higher level products such as local collision frequencies, conductivities and heating rates, along the orbit. The unique complementarity of instrumentation and orbit sampling over a large range of altitudes will be extremely valuable in advancing the science of the LTI region, which is a key region for many space weather phenomena.</p><p><br>High quality visualizations of models and data are very important during the definition of the mission. They allow both experts and newcomers to the field to better comprehend the physics of the LTI region, how it couples with other regions and systems, as well as how Daedalus will be able to sample this region from its unconventional orbit. The presentation will showcase 2D and 3D visuals that were developed during the phase 0 studies, and that make use of empirical and physics-based models of the thermosphere-ionosphere, Earth's magnetic field and simulated satellite orbits.</p>

scholarly journals Zonal mean and tidal dynamics from space: an empirical examination of aliasing and sampling

1997 ◽  
Vol 15 (9) ◽  
pp. 1158-1164 ◽  
Author(s):  
J. M. Forbes ◽  
M. Kilpatrick ◽  
D. Fritts ◽  
A. H. Manson ◽  
R. A. Vincent
Keyword(s):  
Local Time ◽  
Local Times ◽  
Satellite Orbits ◽  
Single Node ◽  
Empirical Examination ◽  
Mesopause Region ◽  
Time Variations ◽  
Radar Measurements ◽  
Mean Circulation ◽  
Insight Into

Abstract. Interpretations of space-based measurements of atmospheric parameters in the mesosphere and thermosphere are complicated by large local-time variations at these altitudes. For this reason, satellite orbits are often preferred which precess through all local times one or more times per season. However, the local-time structure of the atmosphere is inherently non-stationary, which can lead to sampling and aliasing difficulties when attempting to deconvolve the measurements into zonal mean and tidal components. In the present study, hourly radar measurements of mesopause-region winds are used to form a mock data base which can be used to gain insight into implications of the aforementioned problems; the use of actual measurements introduces a realistic element of geophysical temporal variability. Assuming zonal symmetry (i.e., migrating tides superimposed on a zonal mean circulation), the radar measurements are sampled from the satellite perspective for orbital inclinations of 57° and 70°, and compared to the ground or true perspective. These comparisons provide realistic estimates of the errors to be expected when attempting to derive mean and tidal components from space-based measurements. For both diurnal and semidiurnal components, and the quoted satellite inclinations, acceptable errors (3–4m/srms) are obtained for data covering 24h local time (i.e., ascending plus descending nodes); the corresponding errors for single-node data (12h local-time coverage) are of order 8–11m/s, and therefore may not represent reliable estimates of the actual tidal components. There exist certain caveats in connection with the latter conclusion which are discussed.

Representing and Analyzing Sequential Satellite Mission Design Decisions through Anisomorphic Trees and Directed Graphs

2022 ◽  
Author(s):  
Ada-Rhodes Short ◽  
Prachi Dutta ◽  
Ben Gorr ◽  
Luke Bedrosian ◽  
Daniel Selva
Keyword(s):  
Directed Graphs ◽  
Mission Design ◽  
Satellite Mission ◽  
Design Decisions

Mission Design of the Dutch-Chinese FAST Micro-Satellite Mission

2009 ◽  
pp. 187-194 ◽  
Author(s):  
D. Maessen ◽  
J. Guo ◽  
E. Gill ◽  
E. Laan ◽  
S. Moon ◽  
...  
Keyword(s):  
Mission Design ◽  
Satellite Mission

scholarly journals Development of the User Requirements for the Canadian WildFireSat Satellite Mission

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5081
Author(s):  
Joshua M. Johnston ◽  
Natasha Jackson ◽  
Colin McFayden ◽  
Linh Ngo Phong ◽  
Brian Lawrence ◽  
...  
Keyword(s):  
Monitoring System ◽  
Wildland Fire ◽  
Earth Observation ◽  
Mission Design ◽  
User Requirements ◽  
User Engagement ◽  
Satellite Mission ◽  
Wildfire Management ◽  
Fire Monitoring ◽  
Space Agency

In 2019 the Canadian Space Agency initiated development of a dedicated wildfire monitoring satellite (WildFireSat) mission. The intent of this mission is to support operational wildfire management, smoke and air quality forecasting, and wildfire carbon emissions reporting. In order to deliver the mission objectives, it was necessary to identify the technical and operational challenges which have prevented broad exploitation of Earth Observation (EO) in Canadian wildfire management and to address these challenges in the mission design. In this study we emphasize the first objective by documenting the results of wildfire management end-user engagement activities which were used to identify the key Fire Management Functionalities (FMFs) required for an Earth Observation wildfire monitoring system. These FMFs are then used to define the User Requirements for the Canadian Wildland Fire Monitoring System (CWFMS) which are refined here for the WildFireSat mission. The User Requirements are divided into Observational, Measurement, and Precision requirements and form the foundation for the design of the WildFireSat mission (currently in Phase-A, summer 2020).

The contraction of satellite orbits under the influence of air drag - VI. Near-circular orbits with day-to-night variation in air density

1968 ◽  
Vol 303 (1472) ◽  
pp. 17-35 ◽  
Keyword(s):  
Mathematical Theory ◽  
Angular Motion ◽  
Satellite Orbits ◽  
Orbital Eccentricity ◽  
Air Drag ◽  
Rates Of Change ◽  
Gravitational Forces ◽  
Air Density ◽  
Complicated Form ◽  
Time Variations

The theory for the effect of air drag on satellite orbits was developed in Parts I to V of this series of papers on the assumption that the angular motion of perigee is controlled by gravitational forces and is not affected by air drag. If the orbital eccentricity is less than about 0·01, however, and the atmosphere exhibits a substantial day-to-night variation in density, the air drag itself significantly affects the angular motion of perigee. In these circumstances the mathematical theory takes a different and more complicated form, which is developed in the present paper. General equations are derived for the rates of change of parameters specifying the eccentricity and argument of perigee. Complete analytical solutions for the time variations of these parameters are obtained when e is of order 0·001, in two different forms, for (1) high drag, i. e. short lifetime, and (2) low drag. The results are illustrated by numerical examples.

scholarly journals Impacts of Orbital and Constellation Parameters on the Number and Spatiotemporal Coverage of LEO-LEO Occultation Events

2021 ◽  
Vol 13 (23) ◽  
pp. 4849
Author(s):  
Congliang Liu ◽  
Gottfried Kirchengast ◽  
Yueqiang Sun ◽  
Veronika Proschek ◽  
Xin Wang ◽  
...  
Keyword(s):  
Weather Prediction ◽  
Satellite Orbit ◽  
Middle Latitude ◽  
Short Wave ◽  
Low Earth Orbit ◽  
Mission Design ◽  
Satellite Orbits ◽  
Infrared Band ◽  
Orbital Parameters ◽  
Global Coverage

The development of small-satellite technologies allows the low Earth orbit intersatellite link (LEO-LEO) occultation method to observe the Earth’s atmosphere with global coverage and acceptable costs using electromagnetic signals, in which the L/X/K/M band and short-wave infrared band signals have been well demonstrated to be suitable. We hence need to investigate the impacts of orbital and constellation parameters on the number and spatiotemporal distribution of LEO-LEO occultation events for best-possible LEO-LEO occultation mission design and optimization at the targeted mission size. In this study, firstly, an occultation events location simulation model accounting for the right ascension of the ascending node (RAAN) precession was set up and the concept of a time-dependent global coverage fraction of occultation events was defined. Secondly, numerical experiments were designed to investigate the orbital parameters’ impacts and to assess the performance of LEO-LEO occultation constellations, in which the Earth is divided into 5° × 5° latitude and longitude cells. Finally, the number, timeliness, and global coverage fraction of occultation events for two-orbit and multi-orbit LEO-LEO constellations were calculated and analyzed. The results show that: ① the orbit inclination and RAAN are the main impacting parameters followed by orbital height, while the RAAN precession is a relevant modulation factor; ② co-planar counter-rotating receiving and transmitting satellite orbits are confirmed to be ideal for a two-satellite LEO-LEO constellation; ③ polar and near-polar orbit constellations most readily achieve global coverage of occultation events; near-equator orbit constellations with supplementary receiving and transmitting satellite orbit planes also readily form the occultation event geometry, though the occultation events are mainly distributed over low and low-to-middle latitude zones; and ④ a well-designed larger LEO-LEO occultation constellation, composed of 36–72 satellites, can meet the basic requirements of global numerical weather prediction for occultation numbers and timeliness, yielding 23,000–38,000 occultation events per day and achieving 100% global coverage in 12–18 h.

scholarly journals A Simple Graphical Solution for Satellite Orbits

1958 ◽  
Vol 11 (1) ◽  
pp. 98-102 ◽  
Author(s):  
Frank George
Keyword(s):  
Satellite Orbits ◽  
Graphical Solution ◽  
Outlying Island ◽  
Good Insight ◽  
Large Cities ◽  
Simplifying Assumptions ◽  
Insight Into

The first amazement at hearing of the successful launching of the Russian Earthsatellite in October may have been followed in the reader's mind by some bewilderment at its rapid and seemingly erratic progress over all the world's capitals, large cities and outlying island groups. One supposed that a mathematical prediction would be possible but hesitated to attempt anything so complex. Yet, with some simplifying assumptions which must in any case be rather closely approximated by any near satellite that can continue to rotate in orbit, the problem is not difficult and lends itself to graphical treatment. The construction here proposed will give a good insight into the behaviour of such satellites and provide reasonably accurate predictions for a day or two ahead.

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