Why didn't they use a parachute on the lunar lander ?

Moon's atmosphere is very thin. You would have needed a parachute as big as 10 foot ball fields to have even a little bit of effect (even that might not be sufficient)

That's why they used rocket boosters.

Because of the atmosphere. The atmosphere is not dense enough for a parachute to work. Just like on mars. They used balloons to cushion the fall because of the density of the atmosphere. A parachute would do nothing.

Because the moons surface is a near vacuum. A parachute works by resisting the flow of air - without air it's utterly useless!

Parachutes require atmosphere. No such of any relevance for parachutes in the Moon

Because a parachute works by trapping air to slow your fall.

There's no air on the moon so it wouldn't do anything.

It works on Mars because Mars has some air, even though it isn't the same as ours.

Parachutes don't work without atmosphere, of which the moon has essentially none.

Back to school with you..... If they had used a parachute they would have come down pretty hard - killing all on board I imagine.

Not enough gravity on the moon for it to be affective. I meant atmosphere. lol