author = "Prado, Antonio Fernando Bertachini de Almeida",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Multi-tethered maneuvers for a spacecraft passing near the moon",
                 year = "2018",
         organization = "International Astronautical Congress, 69.",
             abstract = "The present paper has the goal of studying the problem of changing 
                         the trajectory of a spacecraft passing close to the Moon using a 
                         multi-tethered assisted maneuver. The idea is to deviate the 
                         trajectory of a spacecraft coming to the Moon from an elliptical 
                         orbit around the Earth. The literature approaches this problem 
                         using several techniques, including impulsive, low thrust and 
                         gravity assisted maneuvers. In the opposite side, the present 
                         paper explores an idea that is already available in the 
                         literature, and uses tethered-assisted maneuvers to change the 
                         orbit of the spacecraft, without fuel consumption. The tethers are 
                         assumed to be fixed in the surface of the Moon and they are used 
                         to rotate a spacecraft that is passing nearby, generating a series 
                         of tethered sling shot effects that changes the energy, velocity 
                         and angular momentum of the spacecraft with respect to the Earth. 
                         The new trajectory will have different values for the Keplerian 
                         elements with respect to the Earth, which can benefit the mission. 
                         The article focus in the energy gains obtained by the maneuver, 
                         considering different values for the tether length, geometry of 
                         approach, number of tethers, etc. It is also studied the tension 
                         that is applied to the tether, such that it is possible to give an 
                         idea of the requirements to build the tether. This study 
                         investigates the use of multiple tethers in order to maximize the 
                         gains of energy while minimizing tether length and tension, which 
                         are two very important factors when building the tether. A 
                         simplified mathematical model of the system is developed, assuming 
                         an inextensible tether with no mass. To solve this problem, 
                         analytical and numerical solutions are combined to obtain the 
                         results, which are the energy variations and tension in the tether 
                         as a function of the number of tethers and the size of each of 
                         them. The main conclusion of the paper is that the proposed scheme 
                         can give large variations of energy to the spacecraft without fuel 
                         expenses, and that the use of several tethers can reduce the 
                         individual size and tension of each tether. So, this study shows 
                         an interesting possibility to maneuver a spacecraft in the future 
                         and can be applied to a large variety of missions.",
  conference-location = "Bremen",
      conference-year = "01-05 oct.",
             language = "pt",
           targetfile = "IAC-18,jorge.pdf",
        urlaccessdate = "13 jun. 2021"