Planar High-Thrust and Low-Thrust Orbital Transfers from Earth to Europa

2004 ◽  
Vol 52 (4) ◽  
pp. 421-439
Author(s):  
Hans Seywald ◽  
Carlos M. Roithmayr ◽  
Daniel D. Mazanek ◽  
Frederic H. Stillwagen ◽  
Patrick A. Troutman ◽  
...  
Keyword(s):  
Low Thrust ◽  
Orbital Transfers ◽  
High Thrust

Fast solution of minimum-time low-thrust transfer with eclipses

2018 ◽  
Vol 233 (7) ◽  
pp. 2699-2714
Author(s):  
Max Cerf
Keyword(s):  
Shooting Method ◽  
Optimal Solution ◽  
Search Space ◽  
Low Thrust ◽  
Indirect Methods ◽  
Transversality Conditions ◽  
Derivative Free ◽  
Fast Solution ◽  
Orbital Transfers ◽  
Zero Values

Optimizing low-thrust orbital transfers with eclipses by indirect methods raises several issues, namely the costate discontinuities at the eclipse entrance and exit, the initial costate guess sensitivity and the numerical accuracy required by the shooting method. The discontinuity issue is overcome by detecting the eclipse within the simulation and applying the costate jump derived analytically from the shadow constraint function. By fixing completely the targeted final position and velocity, the transversality conditions are removed and the shooting problem is recast as an unconstrained nonlinear programming problem. The numerical sensitivity issues are alleviated by using a derivative-free algorithm. The search space is reduced to four angles taking near zero values. This procedure yields a quasi-optimal solution from scratch in few minutes without requiring any specific user’s guess or tuning. The method is applicable whatever the thrust level and the eclipse configuration, as illustrated on transfers towards the geostationary orbit.

The Dynamics of Low-Thrust Spacecraft Manoeuvres

1968 ◽  
Vol 72 (695) ◽  
pp. 925-940 ◽  
Author(s):  
E. G. C. Burt
Keyword(s):  
Power Supplies ◽  
Relativity Theory ◽  
Time Varying ◽  
Low Thrust ◽  
Orbital Elements ◽  
Propulsion Systems ◽  
Optimum Time ◽  
Orbital Transfers ◽  
Electrical Propulsion ◽  
Increasing Function

Summary Orbital manoeuvres by means of impulsive thrusts, such as those available with chemical rockets, are well known, but a different treatment is needed for the small, continuous thrusts that are typical of electrical propulsion systems. It is shown that with the aid of these small forces it is possible to change independently all the orbital elements of a spacecraft, and thus to proceed slowly from a given orbit to any other. For each manoeuvre there exists an equivalent velocity which depends only on the initial and final orbital states, and which can be related directly to the spacecraft propulsion parameters. For any form of propulsion where the propellent acquires some or all of its energy from a separate energy source, as in electrical propulsion, it is found that optimum time-varying relations exist between the flow of mass and of energy, which may also be expressed in terms of the exhaust velocity and the thrust. In particular, the optimum exhaust velocity is shown to be an increasing function of time, related to the way in which the energy is released. The practical realisation of electrical propulsion depends on the development of efficient propulsion units and of lightweight power supplies; these and other spacecraft components are discussed, and a number of examples of orbital manoeuvres are given, including close-Earth, far-Earth and lunar orbits. The paper concludes with a discussion of these orbital transfers in relation to their possible uses, including communication satellites and a test of relativity theory

scholarly journals Optimization of sprint interplanetary trajectories with nuclear bimodal thermal propulsion

2019 ◽  
pp. 74-77
Author(s):  
O. M. Kharytonov ◽  
S. R. Savchenko ◽  
N. Miranda
Keyword(s):  
Optimization Problem ◽  
Electrical Power ◽  
Propulsion System ◽  
Low Thrust ◽  
Small Times ◽  
Limited Power ◽  
Trajectory Method ◽  
Payload Mass ◽  
Interplanetary Missions ◽  
High Thrust

Interplanetary missions require fast and fuel-efficient transfers. Combining small times transfers of high-thrust and efficiency of low-thrust propulsion can provide a good compromise. Saving an amount of fuel from the initial high-thrust burn and using it to correct the trajectory could lead to an economy of fuel. We investigated the optimal way to take advantages of both high and low-thrust propulsion benefits in order to maximize the payload mass of the mission. Using a simple model of ideal engine of limited power and the transporting trajectory method, we determined the analytical expression of final payload mass. The solution of the optimization problem gave us the optimal repartition of fuel between high and low-thrust maneuvers for a given thrust of thermal propulsion and electrical power of low-thrust propulsion system. As the mass of the low-thrust propulsion system depends on the electrical power, we took it into account to determine the optimal electrical power for a sprint trajectory in a given time. As a result, we could obtain the interval of transfer time for which the combination of high and low thrust becomes optimal.

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