35 research outputs found
A procedure for assessing the thermal reemission effects on CBERS 04A
Thermal reemission affects satellite orbits when a recoil force results from the emission of radiation from the satellite surface. In this study, the analysis of the thermal reemission force on the satellite is made separately, that is, when the satellite (CBERS 04A’s main body and the solar panels) are hit by the sunlight and when the satellite is into the shadow. Thus, it is presented an expression in an exponential form in order to explain the behavior of the perturbation due to thermal reemission on the panels when they are inside the Earth’s shadow. Both the time spent into the shadow and the relaxation time of the solar panels allowed an analysis of the behavior of the disturbing acceleration and of the orbital elements, during cooling and heating processes. The results presented in this study are promising in terms of practical applications
Effects of Geopotential and Atmospheric Drag Effects on Frozen Orbits Using Nonsingular Variables
The concept of frozen orbit has been applied in space missions mainly for orbital tracking and control purposes. This type of orbit is important for orbit design because it is characterized by keeping the argument of perigee and eccentricity constant on average, so that, for a given latitude, the satellite always passes at the same altitude, benefiting the users through this regularity. Here, the system of nonlinear differential equations describing the motion is studied, and the effects of geopotential and atmospheric drag perturbations on frozen orbits are taken into account. Explicit analytical expressions for secular and long period perturbations terms are obtained for the eccentricity and the argument of perigee. the classical equations of Brouwer and Brouwer and Hori theories are used. Nonsingular variables approach is used, which allows obtaining more precise previsions for CBERS (China Brazil Earth Resources Satellite) satellites family and similar satellites (SPOT, Landsat, ERS, and IRS) orbital evolution.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)EEL USP LOB, Engn Sch Lorena, BR-12602810 Lorena, SP, BrazilUniversidade Federal de São Paulo UNIFESP, ICT, BR-12231280 Sao Jose Dos Campos, SP, BrazilNatl Inst Space Res INPE DMC, Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo UNIFESP, ICT, BR-12231280 Sao Jose Dos Campos, SP, BrazilFAPESP: 2012/21023-6Web of Scienc
Efeitos de Forças Gravitacionais e Não-Gravitacionais sobre o Movimento Orbital de Satélites Artificiais
Uma teoria para estudar o movimento orbital de satélites artificiais sobre efeitos do arrasto atmosférico e da pressão de radiação solar direta - considerando a sombra da Terra e alguns termos do geopotencial - é desenvolvida analiticamente. A sombra da Terra é modelada utilizando a função sombra (psi), como introduzida por Ferraz Mello: psi igual zero quando o satélite está na região de sombra e igual a um quando é iluminado pelo Sol. As componentes do arrasto são dadas por Vilhena de Moraes baseado no modelo atmosférico TD-88. O método de Hori para sistemas não-canônicos é aplicado para resolver as equações de movimento. Um software para manipulação algébrica é fundamental para fazer os cálculos necessários. Efeitos seculares e periódicos que influenciam no movimento orbital de satélites artificiais são analisados. É dada ênfase aos termos de acoplamento que surgem na solução do sistema de equações diferenciais. Utilizando dados orbitais do satélite CBERS-1 é feito um estudo para analisar ordens de grandeza da variação do semi-eixo maior devidas às perturbações consideradas
Using low Lift-to-Drag spacecraft to perform upper atmospheric Aero-Gravity Assisted Maneuvers
The Gravity Assisted Maneuver has been applied in lots of space missions, to
change the spacecraft heliocentric velocity vector and the geometry of the
orbit, after the close approach to a celestial body, saving propellant
consumption. It is possible to take advantage of additional forces to improve
the maneuver, like the forces generated by the spacecraft-atmosphere
interaction and/or propulsion systems; reducing the time of flight and the need
for multiple passages around secondary bodies. However, these applications
require improvements in critical subsystems, which are necessary to accomplish
the mission. In this paper, a few combinations of the Gravity-Assist were
classified, including maneuvers with thrust and aerodynamic forces; presenting
the advantages and limitations of these variations. There are analyzed the
effects of implementing low Lift-to-Drag ratios at high altitudes for
Aero-gravity Assist maneuvers, with and without propulsion. The maneuvers were
simulated for Venus and Mars, due to their relevance in interplanetary
missions, the interest in exploration, and the knowledge about their
atmospheres. The Aero-gravity Assist maneuver with low Lift-to-Drag ratios at
high altitudes shows an increase of more than 10{\deg} in the turn angle for
Venus and 2.5{\deg} for Mars. The maneuvers increase the energy gains by more
than 15% when compared to the Gravity-Assist. From the Technology Readiness
Levels, it was observed that the current level of development of the space
technology makes feasible the application of Aero-gravity Assisted Maneuvers at
high altitudes in short term
Dynamics of Artificial Satellites around Europa
A planetary satellite of interest at the present moment for the scientific community is Europa, one of the four largest moons of Jupiter. There are some missions planned to visit Europa in the next years, for example, Jupiter Europa Orbiter (JEO, NASA) and Jupiter Icy Moon Explorer (JUICE, ESA). in this paper, we search for orbits around Europa with long lifetimes. Here, we develop the disturbing potential in closed form up to the second order to analyze the effects caused on the orbital elements of an artificial satellite around Europa. the equations of motion are developed in closed form to avoid expansions in power series of the eccentricity and inclination. We found polar orbits with long lifetimes. This type of orbits reduces considerably the maintenance cost of the orbit. We show a formula to calculate the critical inclination of orbits around Europa taking into account the disturbing potential due to the nonspherical shape of the central body and the perturbation of the third body.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Universidade Federal de São Paulo UNIFESP, Inst Ciencia & Tecnol, BR-12331280 Sao Jose Dos Campos, SP, BrazilINPE, Div Space Mech & Control, BR-12227010 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Inst Ciencia & Tecnol, BR-12331280 Sao Jose Dos Campos, SP, BrazilFAPESP: 2011/05671-5FAPESP: 2011/09310-7FAPESP: 2011/08171-3CNPq: 304700/2009-6CNPq: 3003070/2011-0Web of Scienc
Analysis of the orbital evolution of space debris using a solar sail and natural forces
In this work, the orbital evolution of these objects that are located in the
geostationary orbit (GEO) is analyzed. Knowing this, the possibility of using a
solar sail is considered to help to clean the space environment. The main
natural environmental perturbations that act in the orbit of the debris are
considered in the dynamics. Such forces acting in the solar sail can force the
growth of the eccentricity of these objects in the GEO orbit. Several authors
have presented models of the solar radiation pressure considering the
single-averaged model. But, doing a literature research, we found that the
authors consider the Earth around the Sun in a circular and inclined orbit. Our
contribution to the SRP model is in developing a different approach from other
authors, where we consider the Sun in an elliptical and inclined orbit, which
is valid for other bodies in the solar system when the eccentricity cannot be
neglected. The expression of the SRP is developed up to the second order. We
found that the first-order term is much superior to the second-order term, so
the quadrupole term can be neglected. Another contribution is the approach to
identify the initial conditions of the perigee argument (g) and the longitude
of the ascending node (h), where some values of the (g, h) plane contribute to
amplify the eccentricity growth. In the numerical simulations we consider real
data from space debris removed from the site Stuff in Space. The solar sail
helps to clean up the space environment using a propulsion system that uses the
Sun itself, a clean and abundant energy source, unlike chemical propellants, to
contribute to the sustainability of space exploration
Applying the perturbative integral in aeromaneuvers around Mars to calculate the cost
The perturbative integral method was applied to quantify the contribution of
external forces during a specific interval of time in trajectories of
spacecraft around asteroids and under the Luni-solar influence. However, this
method has not been used to quantify the contributions of drag in aerocapture
and aerobraking. For this reason, the planet Mars is selected to apply this
method during an aerogravity-assisted maneuver. Several trajectories are
analyzed, making use of a drag device with area to mass ratios varying from 0.0
to 20.0 m2/kg, simulating solar sails or de-orbit devices. The mathematical
model is based in the restricted three-body problem. The use of this maneuver
makes it possible to obtain the variations of energy in the trajectory,
replacing expensive maneuvers based on fuel consumption. To observe the effects
of the maneuvers, different values of pericenter velocity and altitude were
selected for prograde and retrograde orbits. The innovation of this research is
the application of an integral method to quantify the delta-V of the aero
gravity maneuver, comparing the cost of the maneuver with the traditional
methods of space propulsion. The results allow the identification of orbits
with conditions to capture, and the perturbative maps show the velocity
variations
Analysis of the secular problem for triple star systems
The long-term dynamics of the three-body problem is studied. the goal is to study the motion of a planet (m(1)) around a star (m(0)) that is perturbed by a third-body (m(2)) (a planet or a brown dwarf star). the gravitational potential is developed in closed form up to the fourth order. Taking into account the triple system, it is shown here the evolution of some orbital parameters of the planet (m(1)). A comparison considering models with different orders for the disturbing potential is presented. We show that the behavior of the orbit of the inner planet can flip from prograde to retrograde trajectories. This is due to the third-order term, which strongly affects the eccentricity and inclination. We show that the effect of the fourth order term is to change the times when the phenomenon occurs.Universidade Federal de São Paulo, UNIFESP ICT, Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP ICT, Sao Jose Dos Campos, SP, BrazilWeb of Scienc
Artificial satellites: Resonance effects produced by terrestrial tide
Effects due to resonances in the orbital motion of artificial satellites disturbed by the terrestrial tide are analyzed. The nodal co-rotation resonance, apsidal co-rotation resonance and the Lidov-Kozai's mechanism are studied. The effects of the resonances are analyzed through the variations of the metric orbital elements. Libration and circulation motions for high orbits with high eccentricities are verified for the Lidov-Kozai's mechanism