Assuming constant gravity:

[terminal velocity] = sqrt(2 [ballistic coefficient] [local gravity]
/ [free stream density])

Based upon the above equation if the [free stream density] and the [ballistic coefficient] are both reduced by a half on the same planet then the [terminal velocity] at impact would be the same.

[ballistic coefficient] = [mass] / ([aerodynamic area] [drag coefficient])

Based upon the above equation, [ballistic coefficient] scales with the vehicle's characteristic length, L (assuming mass scales as L^3 and area as L^2).

The zero altitude atmospheric density on Earth is 1.225 kg/m^3.

The zero altitude atmospheric density on Mars is 1.55 x 10^-2 kg/m^3.

The zero altitude gravity on Mars is 0.38 G.

A 5 cm diameter baseball on Earth will have the same terminal impact velocity on Mars if its diameter is 1.7 mm. [scale factor of 30].

This scale factor of 30 is why parachutes are not usable down to the surface of Mars. The parachute is so big that its mass penalty is unjustifiable. If you have every skydived, imagine jumping out of an airplane with a parachute that weighed 10 times as much as what you actually used (parachutes are heavy!).

Gary