Atmospheric close approaches with the Earth considering drag and lift forces

Abstract

A maneuver called "Aero-Gravity Assisted" is known in the literature to increase the energy gains given by a close approach between a spacecraft and a planet using the atmosphere of the planet. In a sequence of studies related to this problem, the present paper studies close approaches between a spacecraft and the Earth, in situations where the passage is close enough to the surface of the Earth such that the spacecraft crosses its atmosphere. The dynamical model considers the atmosphere of the Earth, in terms of drag and lift, the gravitational fields of the Earth and the Sun, assumed to be points of mass, and the spacecraft. The Earth and the Sun are assumed to be in circular coplanar orbits around their common center of mass. The equations of motion are the ones given by the circular planar restricted three-body problem with the addition of the forces generated by the atmospheric drag and lift. The primary objective is to map the variations of energy of the orbits of the spacecraft due to this close approach. The results show how the atmosphere affects the trajectory of the spacecraft, generating situations where the variation of energy changes sign with respect to the gravity part of the maneuver or where they have a zero net result, based in the equilibrium

Effects of the eccentricity of the primaries in powered Swing-By maneuvers

“…This maneuver can also contribute to the capture of spacecrafts by celestial bodies, like shown in Nock and Upholf (1979), Lynam et al (2011) and Brasil et al (2015). Some authors considered this maneuver combined with a passage of the spacecraft by the atmosphere of a planet, known as ''aero-gravity assisted maneuver'', as shown in Lewis and McRonald (1992), Sims et al (1995Sims et al ( , 2000, Lohar et al (1996), Bonfiglio et al (2000), Lavagna et al (2005), Armellin et al (2007) and Gomes et al (2015). A combination of low thrust and gravity assists are used in McConaghy et al (2003), Okutsu et al (2006) and Santos et al (2008).…”

Effects of Bank Angle During Powered Aerogravity-Assist Maneuver

“…The possible uses of this powered maneuver have been analyzed for planets and moons of the solar system [17][18][19][20][21][22][23][24]. When the maneuver is made close to planets that have significant atmosphere and using a spacecraft with wing-body shape (waverider), the AGAM could also be controlled by the direction and/or magnitude of the aerodynamic forces generated during atmospheric flight [2][3][4][25][26][27][28][29][30][31][32]. Since 2015, the combination of the GA with the application of an impulse and a passage by the atmosphere was studied.…”

“…In that sense, the present paper has the goal of studying a new version of this maneuver, where the bank angle is assumed to be variable and constituting in a new form to control the AGAM and PAGAM, which was not used before. The mathematical model selected to analyze the applications of the maneuvers and the resulting trajectories around the center of mass of the orbital system is the circular restricted three-body problem (CRTBP) [36], which is highly accepted in this kind of problems [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The choice of this model is based on our solar system, where the massive body is the sun, the secondary body is a planet with atmosphere used for the maneuver, and the third body is the spacecraft, represented as a massless waverider.…”

“…Previous studies considered the implementation of the impulsive maneuver during the GA [17][18][19][20][21][22][23][24], the control of the AGAM by changing the ballistic parameter and the lift-to-drag ratios, and the inclusion of the direction of the impulse to control the PAGAM [2,25,[33][34][35]. As an extension of those studies, the present paper proposes a new approach to control the direction of lift (component of the aerodynamic force) and to analyze this influence during the PAGAM.…”

On the use of a continuous thrust to find bounded planar trajectories at given altitudes in Low Earth Orbits

“…Satellites in the Low Earth Orbits (LEOs) are highly perturbed by drag 1 , among other forces. The atmospheric drag can be used in maneuvers around the Earth and planets like Mars or Venus [2][3][4] . In general, some kind of thrust is necessary to counteract the losses of altitude and energy due to the atmospheric drag.…”