2021年IOAA理论第3题-火星

英文题目

A spacecraft of mass $$m=5.0\times 10^{4} kg$$ approaches in a parabolic orbit 𝐴𝐵, with respect to Mars. When the spacecraft reaches point 𝐵 of least distance to the center of Mars,$$r_{B} =6.8\times 10^{6} m$$, it undergoes an instantaneous deceleration using its rockets and goes into a perfectly calculated orbit so that it will touch the Martian surface exactly at point 𝐶, diametrically opposite 𝐵, as shown in the figure.