Answer:
5.28 x 10⁻⁹N
Step-by-step explanation:
Given parameters: 
Mass of alien = 71kg 
Distance = 670m 
Mass of ship = 500000kg 
Unknown: 
Gravitational attraction = ? 
Solution:
The gravitational attraction can be found using the Universal gravitation law proposed by Newton; 
 Fg = 
 
 
 G is the universal gravitation constant = 6.67 x 10⁻¹¹ 
 d is the distance
 Fg is the gravitational attraction 
 Fg = 
 = 5.28 x 10⁻⁹N
 = 5.28 x 10⁻⁹N