... Voyager Spacecraft Introduction (This Page) . ... The twin Voyager spacecraft, over the course of a dozen years, drew back the curtain on nearly half of the solar system . From launch in 1977 through the spectacular parting shots in 1989 of Neptune at the outer reaches of the solar system, this pair of gangly, instrument-laden spacecraft explored four planets -- Jupiter , Saturn , Uranus and Neptune -- as well as tens of moons, and the rings and magnetic environments of those planetary systems. ...

... Il s'av?re que l'utilisation la plus efficace de la pouss?e de la fus?e pour atteindre Mars est l'ellipse de transfert de Hohmann. ... Un seul : la condition tr?s rigoureuse sur les positions relatives de la Terre et de Mars ? ... propos du lancement d' un vaisseau spatial de la terre vers Mars, qu'ils devaient partir d'un point not? ... Supposons que le vaisseau spatial d?barqu? sur Mars soit un robot collectant un ?chantillon et qui red?colle imm?diatement pour son voyage de retour. ... Mars, ? ...

From the dawn of history until the beginning of the 17th century the known universe consisted of only 8 bodies: . ... The number of bodies in the solar system increased dramatically in the 19th century with the discovery of the asteroids (464 of which were known at by 1899) but only 9 more "major" bodies were discovered. ... So far, in 20th century 40 more major bodies (and thousands of comets and asteroids) have been discovered (27 by the Voyager probes) more than doubling the count again to 73: . ...