Designing a Reference Trajectory for Frozen Repeat Near-Equatorial Low Earth Orbits

2021 ◽  
pp. 1-10
Author(s):  
Samuel Y. W. Low ◽  
Yongjun Moon ◽  
Wen Tao Liu ◽  
Chek-Wu Tan
Keyword(s):  
Reference Trajectory ◽  
Low Earth Orbits ◽  
Earth Orbits

Atmosphere density changes caused by the motion of spacecrafts in low Earth orbits

2009 ◽  
Vol 15 (1) ◽  
pp. 13-18 ◽  
Author(s):  
A.I. Maslova ◽  
◽  
A.V. Pirozhenko ◽  
Keyword(s):  
Atmosphere Density ◽  
Low Earth Orbits ◽  
Earth Orbits

scholarly journals Solar radiation pressure resonances in Low Earth Orbits

2017 ◽  
Vol 473 (2) ◽  
pp. 2407-2414 ◽  
Author(s):  
Elisa Maria Alessi ◽  
Giulia Schettino ◽  
Alessandro Rossi ◽  
Giovanni B. Valsecchi
Keyword(s):  
Solar Radiation ◽  
Radiation Pressure ◽  
Solar Radiation Pressure ◽  
Low Earth Orbits ◽  
Earth Orbits

scholarly journals A Dynamic Testbed for Nanosatellites Attitude Verification

Aerospace ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 31 ◽  
Author(s):  
Dario Modenini ◽  
Anton Bahu ◽  
Giacomo Curzi ◽  
Andrea Togni
Keyword(s):  
Attitude Determination ◽  
Vision System ◽  
Ground Truth ◽  
Cost Effective ◽  
Air Bearing ◽  
Dynamic Testbed ◽  
Commercial Off The Shelf ◽  
Low Earth Orbits ◽  
Three Degree Of Freedom ◽  
Earth Orbits

To enable a reliable verification of attitude determination and control systems for nanosatellites, the environment of low Earth orbits with almost disturbance-free rotational dynamics must be simulated. This work describes the design solutions adopted for developing a dynamic nanosatellite attitude simulator testbed at the University of Bologna. The facility integrates several subsystems, including: (i) an air-bearing three degree of freedom platform, with automatic balancing system, (ii) a Helmholtz cage for geomagnetic field simulation, (iii) a Sun simulator, and (iv) a metrology vision system for ground-truth attitude generation. Apart from the commercial off-the-shelf Helmholtz cage, the other subsystems required substantial development efforts. The main purpose of this manuscript is to offer some cost-effective solutions for their in-house development, and to show through experimental verification that adequate performances can be achieved. The proposed approach may thus be preferred to the procurement of turn-key solutions, when required by budget constraints. The main outcome of the commissioning phase of the facility are: a residual disturbance torque affecting the air bearing platform of less than 5 × 10−5 Nm, an attitude determination rms accuracy of the vision system of 10 arcmin, and divergence of the Sun simulator light beam of less than 0.5° in a 35 cm diameter area.

Large-scale shielding structures in low earth orbits

2015 ◽  
Vol 109 ◽  
pp. 153-161 ◽  
Author(s):  
D.V. Panov ◽  
M.V. Silnikov ◽  
A.I. Mikhaylin ◽  
I.S. Rubzov ◽  
V.B. Nosikov ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Earth Orbits ◽  
Earth Orbits

scholarly journals A frequency portrait of Low Earth Orbits

2019 ◽  
Vol 131 (8) ◽  
Author(s):  
Giulia Schettino ◽  
Elisa Maria Alessi ◽  
Alessandro Rossi ◽  
Giovanni B. Valsecchi
Keyword(s):  
Low Earth Orbits ◽  
Earth Orbits

scholarly journals Resonant Orbital Dynamics in LEO Region: Space Debris in Focus

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
J. C. Sampaio ◽  
E. Wnuk ◽  
R. Vilhena de Moraes ◽  
S. S. Fernandes
Keyword(s):  
Collision Avoidance ◽  
Frequency Analysis ◽  
Space Debris ◽  
Semimajor Axis ◽  
Orbital Dynamics ◽  
Accurate Information ◽  
The Earth ◽  
Low Earth Orbits ◽  
Line Elements ◽  
Earth Orbits

The increasing number of objects orbiting the earth justifies the great attention and interest in the observation, spacecraft protection, and collision avoidance. These studies involve different disturbances and resonances in the orbital motions of these objects distributed by the distinct altitudes. In this work, objects in resonant orbital motions are studied in low earth orbits. Using the two-line elements (TLE) of the NORAD, resonant angles and resonant periods associated with real motions are described, providing more accurate information to develop an analytical model that describes a certain resonance. The time behaviors of the semimajor axis, eccentricity, and inclination of some space debris are studied. Possible irregular motions are observed by the frequency analysis and by the presence of different resonant angles describing the orbital dynamics of these objects.

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