author = "Ara{\'u}jo, R. A. N. and Winter, O. C. and Prado, Antonio 
                         Fernando Bertachini de Almeida",
          affiliation = "{Universidade Estadual Paulista (UNESP)} and {Universidade 
                         Estadual Paulista (UNESP)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)}",
                title = "Stable retrograde orbits around the triple system 2001 SN263",
              journal = "Monthly Notices of the Royal Astronomical Society",
                 year = "2015",
               volume = "449",
               number = "4",
                pages = "4404--4414",
                month = "June",
             keywords = "celestial mechanics, minor planets, asteroids: general.",
             abstract = "The near-Earth Asteroid 2001 SN263 is a triple system of asteroids 
                         and it is the target of the ASTER mission - First Brazilian Deep 
                         Space Mission. The announcement of this mission has motivated a 
                         study aimed to characterize regions of stability of the system. 
                         Araujo et al., characterized the stable regions around the 
                         components of the triple system for the planar and prograde cases. 
                         Through numerical integrations they found that the stable regions 
                         are in two tiny internal zones, one of them placed very close to 
                         Alpha and another close to Beta, and in the external region. For a 
                         space mission aimed to place the probe in the internal region of 
                         the system those results do not seem to be very interesting. 
                         Therefore, knowing that the retrograde orbits are expected to be 
                         more stable, here we present a complementary study. We now 
                         considered particles orbiting the components of the system, in the 
                         internal and external regions, with relative inclinations between 
                         90 degrees < I <= 180 degrees, i.e. particles with retrograde 
                         orbits. Our goal is to characterize the stable regions of the 
                         system for retrograde orbits, and then detach a preferred region 
                         to place the space probe. For a space mission, the most 
                         interesting regions would be those that are unstable for the 
                         prograde cases, but stable for the retrograde cases. Such 
                         configuration provide a stable region to place the mission probe 
                         with a relative retrograde orbit, and, at the same time, 
                         guarantees a region free of debris since they are expected to have 
                         prograde orbits. We found that in fact the internal and external 
                         stable regions significantly increase when compared to the 
                         prograde case. For particles with e = 0 and I = 180 degrees, we 
                         found that nearly the whole region around Alpha and Beta remain 
                         stable. We then identified three internal regions and one external 
                         region that are very interesting to place the space probe. We 
                         present the stable regions found for the retrograde case and a 
                         discussion on those preferred regions. We also discuss the effects 
                         of resonances of the particles with Beta and Gamma, and the role 
                         of the Kozai mechanism in this scenario. These results help us 
                         understand and characterize the stability of the triple system 
                         2001 SN263 when retrograde orbits are considered, and provide 
                         important parameters to the design of the ASTER mission.",
                  doi = "10.1093/mnras/stv592",
                  url = "http://dx.doi.org/10.1093/mnras/stv592",
                 issn = "0035-8711 and 1365-2966",
             language = "en",
           targetfile = "araujo_stable.pdf",
        urlaccessdate = "29 nov. 2020"