Aerogravity-assist trajectories to the outer planets

Journal of Spacecraft and Rockets, 2002

54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law, 2003

In this paper a preliminary analysis of a wide range of mission opportunities, offered by either aerogravity assist or gravity assist manoeuvres, has been carried out. After an accurate validation of aerogravity assist traditional analytical models, according to several different criteria an extensive global search for optimal trajectories has been performed for highenergy missions, resorting to gravity and aerogravity manoeuvres. To this aim, the new preliminary analysis tool PAMSIT, based on some simplified hypotheses, has been developed. This is capable of efficiently and exhaustively exploring the solutions space for this particular problem, considering the feasibility of a trajectory from both the orbital energy and phasing points of view. Then, all found solutions have been classified according to launch and arrival velocities, time of flight and planetary encounters. A comparison between the opportunities offered by gravity manoeuvres and aerogravity manoeuvres will be presented showing the advantages of the latter in all analysed cases. In particular some interesting options for missions to Jupiter and Neptune will be presented.

In this paper a preliminary analysis of a wide range of mission opportunities, offered by either aerogravity assist or gravity assist manoeuvres, has been carried out. After an accurate validation of aerogravity assist traditional analytical models, according to several different criteria an extensive global search for optimal trajectories has been performed for highenergy missions, resorting to gravity and aerogravity manoeuvres. To this aim, the new preliminary analysis tool PAMSIT, based on some simplified hypotheses, has been developed. This is capable of efficiently and exhaustively exploring the solutions space for this particular problem, considering the feasibility of a trajectory from both the orbital energy and phasing points of view. Then, all found solutions have been classified according to launch and arrival velocities, time of flight and planetary encounters. A comparison between the opportunities offered by gravity manoeuvres and aerogravity manoeuvres will be presented showing the advantages of the latter in all analysed cases. In particular some interesting options for missions to Jupiter and Neptune will be presented.

Journal of Spacecraft and Rockets, 1997

Applied Mathematics and Nonlinear Sciences, 2018

The goal of this paper is to find a combination of conical trajectories, using gravitational assisted maneuvers (swing-by), which perform the transfer from a nearby of the departure planet (Earth) to the vicinity of the arrival planet (Jupiter), making a closest approaches with Mars (flyby) to reduce the fuel consumption for the journey. A detailed description of the mission from Earth— Mars—Jupiter, that used this technique is presented. The table of flyby dates, altitudes of closest approaches is also included. A methodology known as the Patched Conics was used, where the trajectory is divided into three parts: Departure phase, inside of the sphere of influence of the departure planet, Heliocentric phase, during the journey between the planets, Arrival phase, inside the sphere of influence of the arrival planet.

A novel method, called the method of virtual trajectories, is proposed for the preliminary design of multiple gravity-assist (MGA) interplanetary trajectories. Two high-thrust trajectory design problems are considered: the first assumes powered swing-bys (PSB) and coast heliocentric arcs, while the second deals with unpowered swing-bys (USB) and heliocentric arcs each containing at most one deep--space maneuver (DSM). The method comprises two principal stages. First, for a chosen planetary sequence, a database of virtual trajectories is tabulated. Then the database screening and refinement are performed. The results of applying the VT method to the trajectory design of high-priority missions to the Jupiter are given.

Multi-gravity assist (MGA) trajectories are used in space engineering for reducing the cost (propellant and time of ight) of interplanetary missions by using the gravitational eld of celestial bodies. The probes Mariner 10 (mission to Mercury, launched by NASA on 1973), Voyager 1 (furthest humanmade object, NASA, 1977), MESSENGER (mission to Mercury, NASA, 2004) and Cassini (mission to Saturn, NASA-ESA, 1997) are examples. Making use of gravity assist manoeuvres around planets, the velocity vector of the spacecraft relative to the Sun changes during a passage in proximity of the planet, while the velocity vector relative to the planet is rotated (no change in module). The problem of nding the sequence of planets (including resonances, i.e. multiple passages in proximity of the same planet) that guarantees the best transfer to a target space object is a fascinating problem in combinatorics and discrete optimisation. The computational complexity is NP-hard [1]. In this work, a simple and innovative bio-inspired multidirectional algorithm for preliminary analysis of multiple gravity assist planets' sequences is introduced and compared to a branch & cut algorithm.

Acta Astronautica, 2010

In this work, the problem of optimization of interplanetary trajectories with minimum fuel consumption, but with a time limit is studied. It was used a methodology known as the Patched Conics, where the trajectory is divided into three parts: (1) departure phase, inside of the sphere of influence of the departure planet; (2) heliocentric phase, during the journey between the planets; and (3) arrival phase, inside of the sphere of influence of the arrival planet. Furthermore, the possibility of gravitational assisted maneuvers (swing-by) was considered to reduce fuel consumption. In this case the full trajectory would be divided into more parts, depending on the number of maneuvers. Therefore, the goal of this work is to find a combination of conical trajectories, using gravitational assisted maneuvers, which perform the transfer close to the departure planet to the vicinity of the arrival planet, spending minimal fuel with minimal time for the journey. Considering the minimization of time, the solution cannot be the solution of minimum fuel consumption, because the minimization of time and the minimization of fuel are conflicting objectives. Thus, a multi-objective problem must be solved. Hence, a methodology based on the Non Inferiority Criterion (Pareto, 1909 [2]) and the Smallest Loss Criterion (Rocco et al., 2002 [6]) was used, capable of considering multiple objectives simultaneously, without reducing the problem to the case of optimizing a single objective as occur in most methods found in the literature. A mission to Pluto, similar to NASA's New Horizons Mission, was studied considering gravitational assisted maneuvers in Mars, Jupiter and Saturn. Simulating the trajectories and the maneuvers using the Transfer Trajectory Design Programs (Sukhanov, 2004 [13]), several possibilities were analyzed for many combinations of fuel consumption, time of departure, time of arrival and planet used for the swing-by. Then, using the Multiobjective Optimization Program (Rocco et al., 2002 [6]) the problem was solved seeking the best combination. The results can provide good assistance for mission analysis reducing the cost and time.

AIAA/AAS Astrodynamics Specialist Conference and Exhibit, 2004

Missions to the outer planets for spacecraft with a solar-electric propulsion system (SEPS) and that uhilize a single Venus gravity assist are investigated. The trajectories rnaximiZe the delivered mass to the target planet for a range of flight times. A comparison of the trajectory characteristics (delivered mass, launch energy and onboard propulsive energy) is made for various Venus gravity assist opportunities. Methods to estimate the delivered mass to the outer planets are developed.

2010

This paper presents the design of a mission to Europa using solar electric propulsion as main source of thrust. A direct transcription method based on Finite Elements in Time was used for the design and optimisation of the entire low-thrust gravity assist transfer from the Earth to Europa. Prior to that, a global search algorithm was used to generate a set of suitable first guess solutions for the transfer to Jupiter, and for the capture in the Jovian system. In particular, a fast deterministic search algorithm was developed to find the most promising set of swing-bys to reach Jupiter. A second fast search algorithm was developed to find the best sequence of swing-bys of the Jovian moons. After introducing the global search algorithms and the direct transcription through Finite Elements in Time, the paper presents a number of first guess solutions and a fully optimised transfer from the Earth to Europa.