Two identical spaceships are under construction. The constructed length of each spaceship is 1.50 km. After being launched, spaceship A moves away from earth at a constant velocity (speed is 0.850c) with respect to the earth. Spaceship B follows in the same direction at a different constant velocity (speed is 0.500c) with respect to the earth. Determine the length that a passenger on one spaceship measures for the other spaceship.