Properties of the lunar gravity assisted transfers from LEO to the retrograde-GEO

Abstract

The retrograde geostationary earth orbit (retro-GEO) is an Earth’s orbit. It has almost the same orbital altitude with that of a GEO, but an inclination of 180°. A retro-GEO monitor-satellite gives the GEO-assets vicinity space-debris warnings per 12 h. For various reasons, the westward launch direction is not compatible or economical. Thereby the transfer from a low earth orbit (LEO) to the retro-GEO via once lunar swing-by is a priority. The monitor-satellite departures from LEO and inserts into the retro-GEO both using only one tangential maneuver, in this paper, its transfer’s property is investigated. The existence of this transfer is verified firstly in the planar circular restricted three-body problem (CR3BP) model based on the Poincaré-section methodology. Then, the two-impulse values and the perilune altitudes are computed with different transfer durations in the planar CR3BP. Their dispersions are compared with different Sun azimuths in the planar bi-circular restricted four-body problem (BR4BP) model. Besides, the transfer’s inclination changeable capacity via lunar swing-by and the Sun-perturbed inclination changeable capacity are investigated. The results show that the two-impulse fuel-optimal transfer has the duration of 1.76 TU (i.e., 7.65 days) with the minimum values of 4.251 km s−1 in planar CR3BP, this value has a range of 4.249–4.252 km s−1 due to different Sun azimuths in planar BR4BP. Its perilune altitude changes from 552.6 to 621.9 km. In the spatial CR3BP, if the transfer duration is more than or equal to 4.00 TU (i.e., 17.59 days), the lunar gravity assisted transfer could insert the retro-GEO with any inclination. In the spatial BR4BP, the Sun’s perturbation does not affect this conclusion in most cases.

Low Thrust Propelled Close Approach Maneuvers

“…In addition to the pure version of the Swing-By maneuver, which uses only the gravity field of the body approached and the geometry of this passage to give or remove energy of the spacecraft, there are some options of maneuvers that combine different forms of propulsion to increase the flexibility of the maneuver, both in terms of optimizing the consumption and/or following constraints of the mission [6][7][8][9][10][11][12][13][14][15][16][17][18]. The reason to consider those variants of the maneuver is to have more flexibility to achieve the goals of the missions, like gaining or loosing extra energy, or to pass by given regions of space, which would not be possible using only the gravity part of the maneuver.…”