In an orbital system , the gravitational force=centripetal force from the energy principles again .
where G is the gravitational constant , M is the mass of planet , m : mass of satelite , r : orbitral radius
Since GM are both constants ,
At apoapsis , r=4989 , v=1.36
At periapsis , r=2959 , v=??
Now substitute appropriately ,
Divide them to get v which is approximately 1.77 km/s