Abstract:Fuel-optimal three-dimensional trajectories from Earth to Mars for spacecraft powered by a low-thrust rocket with variable speci c impulse capability are presented. The problem formulation treats the spacecraft mass as a state variable, thus coupling the spacecraft design to the trajectory optimization. Gravitational effects of the sun, Earth, and Mars are included throughout an entire trajectory. To avoid numerical sensitivity, the trajectory is divided into segments, each de ned with respect to a different c… Show more
“…The overall trajectory is divided in a sequence of problems, each of them expressed in the primary body reference frame; different segments are then patched together, through boundary constraints at the edge of each segment (direct methods), or through conditions on states and costates (indirect methods). Many applications have been presented, making use of direct methods (Tang and Conway 1995;Herman and Spencer 2002;, indirect methods (Guelman 1995;Vadali et al 2000;Nah et al 2001;Ranieri and Ocampo 2005), or hybrid methods (Pierson and Kluever 1994;Kluever and Pierson 1995).…”
“…The overall trajectory is divided in a sequence of problems, each of them expressed in the primary body reference frame; different segments are then patched together, through boundary constraints at the edge of each segment (direct methods), or through conditions on states and costates (indirect methods). Many applications have been presented, making use of direct methods (Tang and Conway 1995;Herman and Spencer 2002;, indirect methods (Guelman 1995;Vadali et al 2000;Nah et al 2001;Ranieri and Ocampo 2005), or hybrid methods (Pierson and Kluever 1994;Kluever and Pierson 1995).…”
“…So regardless of how long it takes to reach Mars on a certain trajectory, the spacecraft needs the same amount of ∆ . Therefore the main optimizing objective is the time of flight of the transfer, which is mostly dependent on the locations of the planets at a given time [12]. Although there will be a limit to how fast the spacecraft can reach Mars due to the extremely low thrust of the ion engines, we still would like a reasonably quick transfer.…”
As a Blue Waters Student Internship Program project, we have developed a model of interplanetary low-thrust trajectories from Earth to Mars for spacecrafts supplying necessary cargo for future human-crewed missions. Since these cargo missions use ionic propulsion that causes a gradual change in the spacecraft's velocity, the modeling is more computationally expensive than conventional trajectories assuming instantaneous spacecraft velocity changes. This model calculates the spacecraft's time of flight and swept angle at different payload masses with other parameters kept constant and correlates them with known locations of the planets. With parallelization using OpenMP on Blue Waters, its runtime has decreased from 10.55 to 1.53 hours. The program takes a user-selected Mars arrival date and outputs a given range of dates with maximum payload capabilities. This parallelized model will greatly reduce the time required for future mission design projects when other factors like spacecraft solar panel power output may vary with new mission specifications. The internship experience has enhanced the intern's ability to manage a project and will impact positively on his future graduate studies or research career.
“…A great deal of research has been done previously on the design of low-thrust orbital transfers [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]. Refs.…”
Section: Introductionmentioning
confidence: 99%
“…Refs. [3,4,5,6] solved minimum-fuel optimal control problems by solving the Hamiltonian boundary-value problem (HBVP) arising from the calculus of variations. In particular, Ref.…”
Section: Introductionmentioning
confidence: 99%
“…In particular, Ref. [5] used an indirect multiple-shooting method to solve a three-dimensional minimum-fuel Earth-to-Mars orbital trajectory for a low-thrust spacecraft, while Ref. [6] transformed the HBVP into the Cauchy problem through the use of the continuation (homotopic) method.…”
The problem of minimum-time, low-thrust, Earth-to-Mars interplanetary orbital trajectory optimization is considered. The minimum-time orbital transfer problem is modeled as a fourphase optimal control problem where the four phases correspond to planetary alignment, Earth escape, heliocentric transfer, and Mars capture. The four-phase optimal control problem is then
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