When a lunar module landed on the moon, it used thrusters to slow its descent to the surface. when other spacecraft are returned to earth, they use parachutes to slow their descent. why wouldn't a parachute be useful on the moon?

Consider a production line with five stations. station 1 can produce a unit in 9 minutes. station 2 can produce a unit in 10 minutes. station 3 has two identical machines, each of which can process a unit in 12 minutes (each unit only needs to be processed on one of the two machines. station 4 can produce a unit in 5 minutes. station 5 can produce a unit in 8 minutes. which station is the bottleneck station?