Precise Lunar Gravity Assist Transfers to Geostationary Orbits

2006 ◽  
Vol 29 (2) ◽  
pp. 500-502 ◽  
Author(s):  
R.V. Ramanan ◽  
V. Adimurthy
Keyword(s):  
Lunar Gravity ◽  
Gravity Assist ◽  
Lunar Gravity Assist

scholarly journals Design Of Lunar-Gravity-Assisted Escape Trajectories

2020 ◽  
Vol 67 (4) ◽  
pp. 1374-1390
Author(s):  
Lorenzo Casalino ◽  
Gregory Lantoine
Keyword(s):  
Lunar Gravity ◽  
Gravity Assist ◽  
Analytical Treatment ◽  
Direct Optimization ◽  
Earth Asteroid ◽  
Combined Use ◽  
Escape Trajectories ◽  
Gravity Assists ◽  
Lunar Gravity Assist ◽  
Near Earth Asteroids

AbstractLunar gravity assist is a means to boost the energy and C3 of an escape trajectory. Trajectories with two lunar gravity assists are considered and analyzed. Two approaches are applied and tested for the design of missions aimed at Near-Earth asteroids. In the first method, indirect optimization of the heliocentric leg is combined to an approximate analytical treatment of the geocentric phase for short escape trajectories. In the second method, the results of pre-computed maps of escape C3 are employed for the design of longer Sun-perturbed escape sequences combined with direct optimization of the heliocentric leg. Features are compared and suggestions about a combined use of the approaches are presented. The techniques are efficiently applied to the design of a mission to a near-Earth asteroid.

scholarly journals Geostationary Orbit Transfer with Lunar Gravity Assist from Non-equatorial Launch Site

2021 ◽  
Author(s):  
Su-Jin Choi ◽  
John Carrico ◽  
Mike Loucks ◽  
Hoonhee Lee ◽  
Sejin Kwon
Keyword(s):  
Propagation Model ◽  
The Other ◽  
Orbital Energy ◽  
High Fidelity ◽  
Lunar Gravity ◽  
Gravity Assist ◽  
Orbit Transfer ◽  
Launch Site ◽  
Plane Change ◽  
Lunar Gravity Assist

AbstractWe show that it is possible to launch a satellite to Geostationary Equatorial orbit (GEO) from the non-equatorial launch site (Naro Space Center in South Korea) even though that is located in the mid-latitudes of the northern hemisphere. When launched from this site, the equatorial inclination after separation will be 80°. We use a lunar gravity assist (LGA) transfer to avoid the excessive ∆V costs of plane change maneuvers. There are eight possible paths for the LGA; there are four paths consisting of Earth departures and free-return types, and there are two nodes of the Moon’s orbit (ascending and descending). We analyze trajectories over five launch periods for each path using a high-fidelity orbit propagation model. We show that the LGA changes the orbital energy of the “cislunar” free-returns more than for the “circumlunar” free-returns, resulting in less geostationary insertion ∆V for the cislunar free-returns. We also show that the geometrical ∆V variation over the different paths is greater than the seasonal ∆V variation. Our results indicate that an ascending departure and cislunar free-return at the descending node have lower ∆V requirements than the other paths, and lower than described in several previous studies.

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