Their combined momentum after they meet is 0 .
Answer:
The value is 
Explanation:
From the question we are told that
The velocity which the rover is suppose to land with is
The mass of the rover and the parachute is
The drag coefficient is
The atmospheric density of Earth is 
The acceleration due to gravity in Mars is 
Generally the Mars atmosphere density is mathematically represented as

=> 
=> 
Generally the drag force on the rover and the parachute is mathematically represented as

=>
=>
Gnerally this drag force is mathematically represented as

Here A is the frontal area
So

=> 
=> 
To convert 2030 rad into rev, divide 2030 by 2pie. So final answer will be
2030/2 pie =323.08 revolutions.
If I remember correctly (from my studies long time ago) the layers are from the outer to the center:
SiAl : Silicon-Aluminum
SiMa : Silicon-Magnesium (although should be Mg)
NiFe : Nickel-Iron
The SiMa layer should have the lightest elements (Magnesium is lighter than Aluminum)