(1) When the lander falls from the highest point to the surface of Mars, it makes a flat throwing motion, which is regular:

In the horizontal direction, there is x=v1t? (1)

in the vertical direction, there is h=12g1t2? ②

the distance s between the landing point and the highest point satisfies s2=x2+h2③

The gravitational acceleration G1 on the surface of Mars is 2 hv21s2? H2④

(2) The gravity of an object on the surface of Mars is equal to the gravitational force of Mars on the object, and it is obtained that mg1=GMmR2? ⑤

Substitute ④ into ⑤ to get the mass of Mars? M=2hv21R2G(s2? h2)? ?

a: (1) the gravitational acceleration g1 on the surface of Mars is 2hv12s2? H2.

(2) The mass m of Mars is 2hv12R2G(s2? h2)．